Propane tank sizes & gallons left
Propane tanks are filled to only about 80% of their water capacity, leaving room for the gas to expand. The gauge reads percent of total capacity.
| Tank (water capacity) | Max fill at 80% |
|---|---|
| 120 gal | 96 gal |
| 250 gal | 200 gal |
| 500 gal | 400 gal |
| 1,000 gal | 800 gal |
Source: Tennessee Propane Gas Association: reading your tank and the 80/20 rule. Many suppliers suggest calling for a fill before the gauge drops to about 20–30%; check what your supplier recommends. This calculator doesn't estimate usage, because that depends on your home.
Using the gauge safely
- ASME tanks are filled to roughly 80% of water capacity so liquid propane can expand. The dial typically shows percent of tank capacity.
- Many suppliers suggest arranging a delivery before the gauge falls into a low band (often discussed around 20–30%); follow your supplier's policy and any tank-monitor contract you have.
- Do not attempt DIY work on propane piping, regulators, or tank valves. Call your propane company or a licensed tech for leaks, odors, damaged lines, or appliance conversion.
- If you smell gas: leave the area, avoid switches and phones inside, and follow your supplier's emergency instructions / call emergency services as directed on the tank or bill.
Fill-rule overview commonly explained by propane associations and suppliers (see Tennessee Propane Gas Association link above). Emergency response: follow posted supplier guidance.