Calculator
Propane tank refill cost calculator
How many gallons a fill takes, and what it costs, at your state's latest surveyed price.
Tanks are filled to at most 80% of shell capacity — the 80% rule leaves a 20% vapor space for thermal expansion, and is required by law. Gauge readings are approximate and read percent of the tank's full size, so a tank filled to the limit reads 80%. Price is the EIA weekly state residential survey figure, prefilled and editable; your delivered price, taxes, and fees vary by supplier and volume. This is arithmetic on the numbers you enter, not a quote.
Cite
Worked example
A 500-gallon tank holds 400 gallons at the 80% limit. Its gauge reads percent of the tank's full size, so from 30% to 80% the fill is 500 × (80% − 30%) = 250 gallons. At Ohio's average residential price in EIA's Oct 26, 2026 survey, $2.700 a gallon, that fill comes to $675.00 before tax.
The same fill in Ohio's 2025-26 heating season would have cost $602.75 in its lowest survey week (Nov 3, $2.411) and $687.50 in its highest (Feb 16, $2.750). Choosing a state above runs that comparison for any surveyed state, from the seasons table on its state price page.
Why a delivery quote differs from the survey price
EIA asks dealers for the price to a local residential customer on the survey day, before all taxes, and without discounts or premiums for small or large deliveries or extra charges for homes outside the normal delivery area. A quote for a small fill can carry a minimum-delivery charge, and a large one a volume discount, so the calculator's result is the survey-price arithmetic, not a dealer's bill. Contract prices (pre-buy, fixed or capped) are set separately by each dealer; How do propane pre-buy programs work? explains them.
Common questions
How much does it cost to fill a 500-gallon propane tank?
A 500-gallon tank holds about 400 gallons at the 80% fill limit. From a 30% gauge that's roughly 250 gallons; multiply by your price per gallon for the cost. Enter your gauge reading and state price above for the exact figure.
Why can't a propane tank be filled to 100%?
Propane expands as it warms. Filling to 80% leaves a 20% vapor space so the liquid has room to expand without over-pressurizing the tank. It is a safety rule, not a short-fill.
How many gallons is 30% on the gauge of a 500-gallon tank?
The gauge reads percent of the tank's full size, not of the 80% it can hold. 30% of a 500-gallon tank is about 150 gallons in the tank; topping to the 80% (400-gallon) limit adds about 250 gallons.