Fuel & Tanks
500 Gallon Propane Tank Calculator
How many gallons are in your 500-gallon propane tank at 30%? How long will it last? Free calculator converts your gauge reading to gallons and estimates your refill date.
Frequently asked questions
How many gallons are in a 500-gallon propane tank when full?
About 400 gallons. Propane tanks are filled to roughly 80% of their water capacity to leave room for the liquid to expand safely as it warms, so a “500-gallon” tank holds around 400 usable gallons and a full gauge reads about 80%.
How many gallons is 30% on a 500-gallon propane tank?
About 150 gallons. The gauge shows the percentage of the tank’s capacity that is liquid propane, so gallons = 500 × (gauge % ÷ 100). That makes 40% ≈ 200 gallons, 50% ≈ 250 gallons, and 30% ≈ 150 gallons.
How long does a 500-gallon propane tank last in winter?
For whole-home heating, a full 500-gallon tank (about 400 usable gallons) typically lasts 3–4 months at 3–4 gallons per day — but a larger home or a hard winter can cut that to 6–8 weeks. Your actual daily usage is the number that matters; tracking it gives a far more reliable estimate than an average.
How much does it cost to fill a 500-gallon propane tank?
Filling from about 20% to 80% adds roughly 300 gallons. At $2.50–$3.50 per gallon that’s about $750–$1,050, though propane prices swing seasonally and by region. Summer is usually the cheapest time to fill.
What are the dimensions of a 500-gallon propane tank?
A standard residential 500-gallon ASME tank is about 9 feet 11 inches long and 37 inches in diameter, and it’s installed horizontally above ground (or buried). Local codes set minimum distances from buildings and property lines.