How much does it cost to fill a 500-gallon propane tank?
How to estimate a 500-gallon tank refill using usable gallons, tank level and all-in price, with a hypothetical worked example.
Multiply the gallons you actually need by your all-in delivered price. Tanks are generally filled to about 80 percent for safety, so a 500-gallon tank commonly takes up to roughly 400 gallons when empty. Confirm the fill limit with your supplier.
Start with how much room you have
Gallons needed = usable capacity minus gallons already in the tank. A tank at 25 percent of 500 gallons holds about 125 gallons, using the percentage as shown on the gauge relative to tank capacity.
Then price it as a total
Use the all-in delivered price: per-gallon rate plus any flat fees divided by gallons. A benchmark such as the EIA statewide figure is a useful reality check but is not the price you will pay.
Why the real invoice can differ
Gauge readings are approximate, temperature affects volume, and suppliers meter on their own trucks. Expect the invoice to differ from your estimate and ask what it was based on.
Hypothetical: refilling from 25 percent
A made-up 500-gallon tank at 25 percent with an 80 percent maximum fill.
| Usable capacity at 80% | 400 gallons |
|---|---|
| Currently in tank (25% of 500) | 125 gallons |
| Gallons to add | 275 gallons |
| At a hypothetical $3.30 per gallon | $907.50 |
| Plus a hypothetical $50 fee | $957.50, or about $3.48 per gallon |
All dollar figures in this worked example are hypothetical round numbers chosen to show the arithmetic. They are not EIA data, not a quote, and not a prediction.
Checklist
- Read the gauge on a day close to delivery.
- Ask the supplier for their maximum fill percentage.
- Calculate gallons to add and multiply by the quoted rate.
- Add every separate fee.
- Compare the final total with the invoice and ask about differences.
Official sources
- EIA Energy Explained: propane prices. Background on what moves propane prices.
- Propane Education & Research Council: propane safety in your home. Industry safety guidance for homeowners.
- EIA Colorado residential propane series (W_EPLLPA_PRS_SCO_DPG). The official weekly Colorado series with observation dates.
Related guides
Frequently asked questions
- Is 400 gallons exact?
- It is a common estimate for 80 percent fill. Your supplier's practice governs.
- Can I fill to 100 percent?
- Tanks are not normally filled to full capacity; expansion room is a safety feature.
- Do you quote prices?
- We do not. Ask a supplier for a delivered quote covering your exact address, gallons, tank terms, and fees.
Content reviewed October 5, 2026. Dates of data observations are separate and shown at the source.
Location picks reflect Colorado Propane Prices’ editorial judgment, not independent testing. Confirm every supplier’s coverage and delivered price directly. General information only; not a quote, not professional advice, and no price is guaranteed.