Tank Volume Calculator
Calculate tank volume for 6 shapes: rectangular, horizontal/vertical cylinder, oval, capsule, sphere. Add fill level and liquid type for filled volume and weight.
🛢️ Tank Volume Calculator
TOTAL CAPACITY
FILLED VOLUME (100%)
💡 How to Calculate Tank Volume
Tank volume is the total internal capacity of a storage tank. Knowing exact volume is essential for ordering fuel, sizing pumps, calculating chemical dosages, estimating fill time, and determining structural loads.
The calculator above supports 6 tank shapes, calculates filled volume at any fill level, and estimates liquid weight for 5 common liquids.
Convert volume with our cubic feet calculator. For pipes, see our pipe volume calculator. Calculate fill time with our flow rate calculator.
Tank Volume Formulas
| Shape | Formula | Variables |
|---|---|---|
| Rectangular | V = L × W × H | L = length, W = width, H = height |
| Cylinder (H) | V = π × r² × L | r = diameter ÷ 2, L = length |
| Cylinder (V) | V = π × r² × H | r = diameter ÷ 2, H = height |
| Oval | V = π × a × b × L | a = width ÷ 2, b = height ÷ 2, L = length |
| Capsule | V = πr²L + ⁴⁄₃πr³ | r = diameter ÷ 2, L = cylinder length |
| Sphere | V = ⁴⁄₃πr³ | r = diameter ÷ 2 |
All formulas give volume in cubic inches. Divide by 231 for US gallons, or multiply by 0.016387 for liters.
Common Propane Tank Sizes
| Tank Size | Capacity | Dimensions (approx) | Weight (full) |
|---|---|---|---|
| 20 lb (BBQ) | 4.6 gal | 12" dia × 18" tall | 38 lbs |
| 30 lb | 7.0 gal | 12" dia × 24" tall | 55 lbs |
| 40 lb | 9.4 gal | 12" dia × 29" tall | 72 lbs |
| 100 lb | 23.6 gal | 15" dia × 48" tall | 170 lbs |
| 120 gal | 96 gal (80% fill) | 30" dia × 52" long | 500 lbs |
| 250 gal | 200 gal (80% fill) | 30" dia × 92" long | 960 lbs |
| 500 gal | 400 gal (80% fill) | 37" dia × 120" long | 1,900 lbs |
| 1,000 gal | 800 gal (80% fill) | 41" dia × 192" long | 3,700 lbs |
Propane tanks are filled to 80% capacity to allow for thermal expansion. The "gallon" rating is total tank capacity, not usable propane.
Common Tank Dimensions
| Tank Type | Dimensions | Capacity |
|---|---|---|
| 55-gallon drum | 23" dia × 34" tall | 55 gal |
| 275-gal oil tank | 27" × 44" × 60" | 275 gal |
| 330-gal IBC tote | 48" × 40" × 46" | 330 gal |
| Water heater (40 gal) | 18" dia × 60" tall | 40 gal |
| Water heater (50 gal) | 20" dia × 60" tall | 50 gal |
| Septic tank (1,000 gal) | 60" × 60" × 96" | ~1,000 gal |
Liquid Weight Reference
| Liquid | lbs/gallon | Weight of 100 gal |
|---|---|---|
| Water | 8.34 | 834 lbs |
| Diesel fuel | 7.1 | 710 lbs |
| Gasoline | 6.3 | 630 lbs |
| Heating oil | 7.2 | 720 lbs |
| Propane (liquid) | 4.2 | 420 lbs |
Structural note: A 1,000-gallon water tank weighs over 8,300 lbs when full. Always verify floor/foundation capacity before placing large tanks indoors.