A 500-gallon propane tank is filled to about 400 gallons, which holds roughly 36.6 million Btu of heat. A home that burns the EIA’s average propane-heating household amount, 494 gallons from November to March, uses a full tank in about 118 days, or just under four months. Hot-water and cooking customers can stretch a fill across a year or more, and a whole-house generator can empty it in about four and a half days of full-load running.
The answer moves with three things: how full the tank really is, how many gallons your home burns each month, and the dollars per gallon when the delivery truck arrives. Each is kept explicit in the tables below. Propane prices themselves are covered in Propane Prices, Explained, and the oil-tank version of the same question is in how much heating oil a house uses.
What a 500-gallon tank holds
The 500 is a water capacity: the volume of water the steel shell could hold. Propane is a liquid that expands as it warms, so the shell is never filled to the top. The Propane Education and Research Council (PERC) says propane containers are typically filled to 80 percent of their capacity to allow for that expansion, and that ASME tanks with an automatic stop-fill valve stop filling when the liquid reaches 80 percent by volume. A fire-service training text published by New Jersey’s Division of Fire Safety says propane is filled to about 85 percent of water capacity. The two figures differ because the real limit depends on the container and the liquid temperature at the time of filling. This page uses 80 percent, the lower of the two figures and the one PERC states directly.
Table 1. Residential tank sizes, usable propane at 80 percent, and the heat inside
| Water capacity (gal) | Typical shell (diameter x length) | Propane at 80% (gal) | Heat at 91,500 Btu per gal (million Btu) |
|---|---|---|---|
| 120 | 24 in x 5 ft 6 in | 96 | 8.8 |
| 250 | 30 in x 7 ft 8 in | 200 | 18.3 |
| 320 | 32 in x 9 ft | 256 | 23.4 |
| 500 | 38 in x 10 ft | 400 | 36.6 |
| 1,000 | 40 in x 16 ft 8 in | 800 | 73.2 |
Sources: PERC Propane Technical Pocket Guide, Table 4 (dimensions, which vary by manufacturer), Table 1C (91,500 Btu per gallon) and the 80 percent fill guidance in PERC's agricultural dispensing guide, all checked October 23, 2026. Usable gallons and heat are this page's arithmetic.
The float gauge on a typical residential tank is marked in percent of the tank’s volume, so this page converts percent to gallons on the 500-gallon shell: a freshly filled tank reads 80, which is 400 gallons, and a reading of 62 is 310 gallons. Table 3 below also tracks a 20 percent line, 100 gallons, which this page treats as the point where the next delivery should already be scheduled. That 100-gallon reserve is a planning assumption chosen for the tables, not a regulation. A truck that cannot get up a snowy driveway, or a supplier backed up after a cold snap, can turn a 100-gallon cushion into a week.
Turning a winter of gas use into dates
The EIA’s Winter Fuels Outlook 2026-27, released October 6, 2026, gives the base-case propane consumption of a household that heats mainly with propane, month by month, for the Northeast, Midwest and South. The national figure is a household-weighted average of those three regions. The numbers are averages across homes of every size and efficiency, and they combine space heating with the other propane uses in those homes, so a given house can sit well above or below them.
Table 2. Propane gallons per household by month, base case, winter 2026-27
| Region | Nov | Dec | Jan | Feb | Mar | Nov-Mar total | Price forecast ($/gal) |
|---|---|---|---|---|---|---|---|
| Northeast | 81 | 108 | 122 | 106 | 97 | 514 | $3.28 |
| Midwest | 102 | 140 | 156 | 130 | 111 | 639 | $2.04 |
| South | 59 | 83 | 91 | 72 | 60 | 365 | $3.19 |
| U.S. average | 80 | 109 | 119 | 99 | 87 | 494 | $2.52 |
Source: EIA Winter Fuels Outlook 2026-27, propane consumption and price tables, checked October 23, 2026. The published totals are 515, 641, 365 and 494 gallons; monthly values are rounded, so the Northeast months add to 514 and the Midwest months to 639. Propane is a household-weighted average of the Northeast, Midwest and South.
January is the peak in every region: 119 gallons for the average household against 80 in November and 87 in March. The Midwest burns the most gallons because it has the coldest winter of the three, with 1,210 heating degree days in January, while the South burns the fewest at 542. The EIA’s own method for the outlook holds space heating proportional to heating degree days and spreads the other uses evenly across days, which is also the logic of the worked example further down.
To turn those monthly gallons into dates, assume a delivery fills the tank to 400 gallons on November 1 and that each month’s use is spread evenly across its days. The table walks the tank down from there.
Table 3. A 400-gallon fill on November 1, walked down by the EIA monthly profile
| Household profile | Nov-Mar gallons | Hits 100 gal left | Empty |
|---|---|---|---|
| Northeast | 514 | Jan 28 (day 89) | Feb 24 (day 116) |
| Midwest | 639 | Jan 12 (day 73) | Feb 1 (day 92) |
| South | 365 | Feb 26 (day 118) | Not before April |
| U.S. average | 494 | Jan 29 (day 90) | Feb 26 (day 118) |
Model dates, not predictions: uniform use within each month, winter 2026-27 base case, a fill on November 1. 'Not before April' means the model still has fuel on March 31. Day counts start at November 1 = day 0.
Read the dates as a spread, not a promise. The Midwest household, with the highest winter burn, is down to 100 gallons on Jan 12, 73 days after the fill, and the tank is dry by Feb 1. The model southern household reaches the 100-gallon line on Feb 26 and still has fuel on March 31. The national average household reaches it on Jan 29 and empties the tank on Feb 26. So one fill on November 1 does not carry the Northeast, Midwest or national-average household to April, and it carries the southern one only if the owner is willing to run near the reserve in late February. Where your house sits among those rows is a matter of its size, insulation, heating equipment and thermostat, and the table cannot see any of it.
Scaling the table to your own house
Because the table is linear, a home that burns more or less than the average moves the dates in proportion. Table 4 applies five multiples to the national profile.
Table 4. The same fill, for homes that burn a multiple of the U.S. average
| Burn vs U.S. average | Nov-Mar gallons | Hits 100 gal left | Empty |
|---|---|---|---|
| 0.50x | 247 | Not before April | Not before April |
| 0.75x | 371 | Feb 26 (day 118) | Not before April |
| 1.00x | 494 | Jan 29 (day 90) | Feb 26 (day 118) |
| 1.50x | 741 | Jan 3 (day 64) | Jan 20 (day 81) |
| 2.00x | 988 | Dec 20 (day 50) | Jan 3 (day 64) |
Computed from Table 2 (U.S. average profile) with the same assumptions as Table 3. A home at 2.0x burns 988 gallons in five months, more than two full 400-gallon fills.
The 0.5x row shows how much slack lives in the average. A home that burns half the national figure finishes March with the tank still over half full, which is why fixed schedules and gauge readings often disagree for small or well-insulated homes. At the other end, the 2.0x row would need a second delivery before Christmas. For a view that is not limited to November through March, the EIA’s 2020 residential survey (Table CE2.1) records homes whose main heating fuel is propane using about 656 gallons a year for all purposes, which is the right order of magnitude to set beside the five-month figure of 494 gallons. How EIA builds its winter averages is covered in the Winter Fuels Outlook guide.
How the nameplate ceiling compares with real burn
Every appliance has a maximum hourly input printed on its nameplate. The Propane Technical Pocket Guide reproduces approximate figures from NFPA 54, the National Fuel Gas Code, and dividing them by the heat in a gallon gives the fuel that appliance burns when it runs flat out. The tank’s 400 gallons then translates into hours of continuous running.
Table 5. Hours of continuous full-input burn in a 400-gallon fill
| Appliance (approximate input, Btu per hour) | Gallons per hour | Gallons per day | Hours per fill | Days per fill |
|---|---|---|---|---|
| Warm-air furnace, single-family home (100,000) | 1.09 | 26.2 | 366 | 15.2 |
| Hydronic boiler, space heating only, single-family home (100,000) | 1.09 | 26.2 | 366 | 15.2 |
| Storage water heater, 50 gallon (50,000) | 0.55 | 13.1 | 732 | 30.5 |
| Freestanding range (65,000) | 0.71 | 17.0 | 563 | 23.5 |
| Clothes dryer (35,000) | 0.38 | 9.2 | 1,046 | 43.6 |
Sources: PERC Propane Technical Pocket Guide, Table 3A (reprinted from NFPA 54-2018) and Table 1C; checked October 23, 2026. These are ceilings for appliances running 100 percent of the time, which none do.
The comparison that matters is between that ceiling and the EIA monthly figure. A furnace at the full 100,000 Btu an hour would burn 1.09 gallons an hour, or 26.2 gallons a day. The U.S. average household’s January use is 3.84 gallons a day for everything, including hot water and cooking. Even if every January gallon went to the furnace, it would be running about 15 percent of the time. That is the duty cycle to hold in mind when a nameplate Btu number makes a tank look as if it would drain in a fortnight. It also explains why the firing rate of a boiler or furnace is a poor stand-in for what a season costs: the time it spends off, set by weather and the building, dominates.
What the tank can deliver when it is cold
Gallons in the tank and gas at the burner are different things. Liquid propane has to boil, and the heat for that comes from the air through the tank wall. A colder day and a lower liquid level both reduce the rate. The PERC pocket guide tabulates a maximum intermittent withdrawal by tank size and by the lowest outdoor temperature averaged over 24 hours, assuming the tank is half full, relative humidity is 70 percent and the tank is aboveground.
Table 6. Maximum intermittent withdrawal, Btu per hour, tank half full, no frosting
| Lowest 24-hour average temperature | 250 gal | 500 gal | 1,000 gal | 500 gal as gallons per hour |
|---|---|---|---|---|
| 40 F (4 C) | 288,100 | 478,800 | 852,800 | 5.23 |
| 20 F (-7 C) | 216,800 | 360,400 | 641,900 | 3.94 |
| 0 F (-18 C) | 180,600 | 300,100 | 534,500 | 3.28 |
| -10 F (-23 C) | 177,400 | 294,800 | 525,400 | 3.22 |
| -20 F (-29 C) | 145,800 | 242,300 | 431,600 | 2.65 |
Source: PERC Propane Technical Pocket Guide, Table 5, checked October 23, 2026. For continuous loading the guide says to multiply these withdrawal rates by 0.25. The last column divides by 91,500 Btu per gallon.
Against that, consider a furnace, a 50-gallon water heater, a range and a dryer with the Table 5 inputs of 100,000, 50,000, 65,000 and 35,000 Btu an hour. Added together that is 250,000 Btu an hour, which a half-full 500-gallon tank can supply at 0 degrees (300,100 Btu an hour) but not at minus 20 degrees (242,300). The sum assumes everything fires at once, which is rare, and the guide’s intermittent-loading basis fits a house better than a continuous one. Nothing here says a typical house has a problem. The point is that a nearly empty tank in a cold snap can be short of gas while still holding liquid, a state the gauge percentage does not warn about, and it is one more reason to schedule a delivery before the level is low.
PERC also notes that underground tanks sit in soil with a steadier temperature through the year, which stabilizes their vaporization rates, while an aboveground tank follows the air. Sizing a tank for a particular load and winter low is an installer’s calculation. Equipment, replacement and tank-install decisions are covered by the sister site EnergyBS, not here.
Running a generator from the same tank
Generac publishes propane consumption for its 22 kW standby generator, model 7042, at half and full load: 89 and 135 cubic feet an hour, equal to 2.53 and 3.71 gallons an hour. The page for the model 7260 lists the same cubic-foot figures and 2.45 gallons an hour at half load. Using the guide’s factor of 2,488 Btu per standard cubic foot, 135 cubic feet an hour is roughly 335,880 Btu an hour, more than three times the furnace row in Table 5.
Table 7. A 22 kW generator (Generac 7042) on a 400-gallon fill and on the 300 gallons above the 100-gallon reserve
| Load | Gallons per hour | Hours on 400 gal | Days on 400 gal | Hours on 300 gal | Days on 300 gal |
|---|---|---|---|---|---|
| 50 percent | 2.53 | 158 | 6.6 | 119 | 4.9 |
| 100 percent | 3.71 | 108 | 4.5 | 81 | 3.4 |
Source: Generac Power Systems product page for the 22 kW standby generator, model G007042, LP consumption at 50 and 100 percent load, checked October 23, 2026. Hours are the tank gallons divided by the generator's hourly figure; the furnace and water heater draw from the same tank and are not included.
A generator rarely sits at one load for days, so read the table as a bound. The practical comparison is the ratio: even at half load the generator burns 16 times the gallons per day that an average household burns in January (60.7 gallons a day against 3.8). A tank that comfortably covers a heating season can be a few days of backup power, and the two demands add together when both are running in a storm.
The dollars per fill
The EIA’s Heating Oil and Propane Update collects residential propane prices from October through March, in dollars per gallon excluding taxes. The week of October 19, 2026 shows a national average of $2.689, with a wide spread between regions. Applied to a 400-gallon fill and to the 300 gallons between the 20 and 80 percent marks:
Table 8. Cost of a fill at EIA residential prices, week of October 19, 2026
| Area | Price ($/gal, no tax) | 300-gallon refill | 400-gallon fill | Winter at 494 gal |
|---|---|---|---|---|
| U.S. average | $2.689 | $807 | $1,076 | $1,328 |
| East Coast (PADD 1) | $3.693 | $1,108 | $1,477 | $1,824 |
| New England (PADD 1A) | $3.872 | $1,162 | $1,549 | $1,913 |
| Midwest (PADD 2) | $2.156 | $647 | $862 | $1,065 |
| Gulf Coast (PADD 3) | $3.034 | $910 | $1,214 | $1,499 |
| Rocky Mountain (PADD 4) | $2.340 | $702 | $936 | $1,156 |
| U.S. average, Oct 2025 - Mar 2026 heating season | $2.553 | $766 | $1,021 | $1,261 |
Source: EIA Heating Oil and Propane Update (series W_EPLLPA_PRS_NUS_DPG for the U.S. weekly residential price), week of 10/19/26, checked October 23, 2026. The last row is the average of the 26 weekly U.S. residential propane prices from October 2025 through March 2026. Dealer delivery charges, taxes and tank rental are not in the EIA price.
Three observations. First, the same 400 gallons costs $686 more in New England than in the Midwest this week. Second, the winter total at the 494-gallon national average works out near $1,328 at this week’s price and $1,261 at last winter’s average. Third, the EIA says changes in wholesale propane reach retail within about four to six weeks, so a fall rise in the Mont Belvieu price shows up in January fills. The Winter Fuels Outlook guide explains how that forecast is built, and the fuel comparison puts a gallon of propane next to oil, gas and electricity on a per-Btu basis.
Your own tank: a two-reading method with a worked example
The EIA’s method says space heating is proportional to heating degree days and everything else is spread evenly across the days. That is enough to calibrate a house from two months of gauge readings. Use gallons used = a x days + b x heating degree days, where a is the flat daily use and b the gallons per degree day. Below is a hypothetical Northeast home, not a real customer, with a fill to 400 gallons (80 percent) on November 1, a gauge of 62 percent on November 30 and 36 percent on December 31.
Table 9. Calibrating a hypothetical home from two readings, then projecting January to March
| Month | Days | Heating degree days (EIA NE base case) | Gallons used | Tank level at month end (gal) | Gauge at month end |
|---|---|---|---|---|---|
| November (read) | 30 | 633 | 90 | 310 | 62% |
| December (read) | 31 | 917 | 130 | 180 | 36% |
| January (projected) | 31 | 1,071 | 152 | 28 | 6% |
| February (projected) | 28 | 914 | 129 | 0 | empty |
| March (projected) | 31 | 795 | 113 | 0 | empty |
Heating degree days are the EIA Winter Fuels Outlook 2026-27 Northeast base case (population-weighted, 65 F base). The two readings are invented for the example. Solving the two equations gives the flat use and the slope below; projections assume the EIA base-case weather.
Solving the two months gives a flat use of 0.03 gallons a day and a slope of 0.141 gallons per heating degree day. Because the EIA heating degree days are a forecast, the January to March rows are only as good as the weather assumption, and the EIA also publishes colder and warmer side cases for that reason. In the base case this home reaches the 100-gallon line about January 16, with 28 gallons left on January 31. The flat daily figure is the weakest number here, because two readings cannot separate it cleanly from the weather term, so lean on the projection rather than on the split. A home that burns 10 to 20 percent more than the Northeast average, as this one does, should have its second delivery on the calendar for the first half of January. Two readings are enough only if they are taken at the same hour of the day, with the tank not filled in between; a delivery in the middle of a month needs the invoice gallons added back in.
Cooking, water heating and the other uses
A tank that serves only a range and a water heater lives on a different timescale. The EIA’s 2020 residential energy consumption survey measured the propane used by U.S. homes for each end use, and the four largest are below. Space heating takes about three-quarters of the propane used in the four end uses combined, which is why a home without propane heat has so much slack in a 500-gallon tank.
Table 10. U.S. residential propane consumption by end use, 2020
| End use | Trillion Btu | Share of these four | Equivalent million gallons at 91,500 Btu per gal |
|---|---|---|---|
| Space heating | 274.0 | 76.7% | 2,995 |
| Water heating | 69.4 | 19.4% | 758 |
| Cooking | 11.6 | 3.2% | 127 |
| Clothes dryers | 2.3 | 0.6% | 25 |
| Total of the four | 357.3 | 100.0% | 3,905 |
Source: EIA Residential Energy Consumption Survey 2020, Table CE5.2 (detailed household natural gas and propane end-use consumption, totals), released June 2023, revised March 2024, checked October 23, 2026. Pool heaters, hot tub heaters and other uses are outside the four rows. Gallons are this page's conversion.
Rural homes account for most of it: the same table shows 231.4 of the 274.0 trillion Btu of propane space heating in rural areas, about 84 percent. That matters for delivery. A rural home is often at the end of a long delivery route, so the practical question is less how many days the tank covers than how many days the truck needs to reach it.
Questions about 500-gallon propane tanks
How many gallons can you actually put in a 500-gallon propane tank?
About 400. The 500 is the tank's water capacity, and propane tanks are typically filled to 80 percent of capacity to leave room for the liquid to expand as it warms (Propane Education and Research Council). A fire-service training text from New Jersey puts the figure at about 85 percent of water capacity, so the exact limit depends on the tank, the temperature and the rules your supplier follows. The data plate and your supplier's fill record settle it for your tank.
How long will a 500-gallon propane tank last for heating a house in winter?
For a home that burns the EIA's U.S. average for propane heating households (494 gallons from November to March), a 400-gallon fill that starts on November 1 reaches about 100 gallons left around Jan 29 (day 90) and runs dry around Feb 26 (day 118). A home burning 1.5 times the average reaches the 100-gallon mark around Jan 3 (day 64). These are model dates from monthly averages, so your own gauge readings beat them.
How long does a 500-gallon tank last for cooking and hot water only?
Far longer than for heating, but there is no honest single number. In the EIA's 2020 residential survey tables, propane space heating accounts for 274.0 trillion Btu nationally against 69.4 for water heating, 11.6 for cooking and 2.3 for clothes dryers, so heating is about three-quarters of those four uses. A home with no propane heat uses a fraction of a heating home's gallons. Track your own deliveries for a year, because family size and appliance mix move the answer more than the tank does.
How long will a 500-gallon propane tank run a whole-house generator?
Generac's published figures for its 22 kW model 7042 are 2.53 gallons an hour on propane at 50 percent load and 3.71 at full load. A 400-gallon fill covers about 158 hours at half load or 108 hours at full load, before counting the furnace and water heater drawing from the same tank. Cold limits how fast a half-empty tank can vaporize, so the installer's sizing matters as much as the gallons.
When should I schedule a propane delivery?
The EIA's Winter Fuels Outlook notes that many heating oil and propane users buy supplies ahead of winter and refill as needed. This page uses a reserve of 100 gallons, a fifth of the tank, as a planning marker for when to have the next delivery on the calendar. That reserve is an assumption made for the tables, not a regulation or an industry standard, and automatic-delivery customers should follow their supplier's schedule and check the gauge before storms.
Does cold weather make a propane tank run out sooner?
Two ways. A colder month burns more fuel, which is the main effect in the tables above: the U.S. average household uses 119 gallons in January against 80 in November. Separately, liquid propane boils off from the tank walls, and a colder, lower tank vaporizes more slowly. The Propane Education and Research Council's guide lists 300,100 Btu an hour for a half-full 500-gallon tank at 0 degrees Fahrenheit and 242,300 at minus 20, so a low tank in a hard freeze can fail to keep up even with fuel inside it.
Is an underground 500-gallon tank different?
The volume and the fill rule are the same. The difference the Propane Education and Research Council describes is thermal: underground tanks sit in soil that stays at a steadier temperature through the year, which stabilizes vaporization rates, while an aboveground tank follows the air temperature. Planning for the tank location belongs with the installer, not with this page.
Data and sources: Propane Education and Research Council, Propane Technical Pocket Guide, checked October 23, 2026 (Table 1C 91,500 Btu per gallon; Table 3A appliance inputs reprinted from NFPA 54-2018; Table 4 tank dimensions; Table 5 withdrawal rates; 2,488 Btu per SCFH). PERC, Dispensing Propane Safely into Agricultural Equipment, checked October 23, 2026 (80 percent fill guidance). New Jersey Department of Community Affairs, Division of Fire Safety, Recognizing and Avoiding the Hazards of Propane, checked October 23, 2026 (about 85 percent of water capacity). EIA, Winter Fuels Outlook 2026-27, released October 6, 2026, checked October 23, 2026 (propane gallons and prices by region and month; heating degree days by region and month; four-to-six-week pass-through of wholesale prices). EIA, Heating Oil and Propane Update, week of October 19, 2026, checked October 23, 2026, and the weekly residential propane series W_EPLLPA_PRS_NUS_DPG, same date (October 2025 through March 2026 average of weekly prices computed by this page). EIA, Residential Energy Consumption Survey 2020, Table CE5.2, and Table CE2.1 (656 gallons per year, homes with propane as the main heating fuel), checked October 23, 2026. Generac Power Systems, 22 kW standby generator, model 7042 and the model 7260 page, checked October 23, 2026. Every day count, share, scaled row, cost and projection on this page is arithmetic by PetroEyes on those inputs. The Table 9 home is hypothetical.