Gallons to Cubic Feet CalculatorTank Size & Storage Space Planner
Convert gallons to cubic feet (ft³) instantly with our free calculator. Essential tool for determining water tank dimensions, planning storage space, and calculating container sizes. When you know how many gallons you need to store, use this calculator to find out how much physical space is required. Supports both US gallons (liquid) and UK (Imperial) gallons for international users. Perfect for homeowners buying water tanks, contractors planning installations, warehouse managers organizing liquid storage, and anyone needing to convert liquid capacity to physical volume measurements.
Calculate Gallons to Cubic Feet
Convert ft³ to gallons for water tanks, aquariums, and pools
Enter the volume in gallons
Result in cubic feet gallons
Also equals:
Liters
378.54 L
Cubic Inches
23,100 in³
Cubic Yards
0.5 yd³
Suggested Tank Dimensions for 100 US gal:
Calculation:
100 US gal × 0.133681 = 13.37 ft³
Formula: Cubic Feet = US Gallons × 0.133681
Gallons to Cubic Feet Conversion Table
Quick reference for common gallon to ft³ conversions (US & UK).
| US Gallons | Cubic Feet (ft³) | UK Gallons | Common Use |
|---|---|---|---|
| 1 gal | 0.13 ft³ | 0.83 gal | Small container |
| 5 gal | 0.67 ft³ | 4.16 gal | Bucket |
| 10 gal | 1.34 ft³ | 8.33 gal | Small aquarium |
| 20 gal | 2.67 ft³ | 16.65 gal | Medium aquarium |
| 30 gal | 4.01 ft³ | 24.98 gal | 30 gal water heater |
| 50 gal | 6.68 ft³ | 41.63 gal | 50 gal water heater |
| 75 gal | 10.03 ft³ | 62.45 gal | 75 gal aquarium |
| 100 gal | 13.37 ft³ | 83.27 gal | 100 gal aquarium |
| 200 gal | 26.74 ft³ | 166.53 gal | Large aquarium |
| 500 gal | 66.84 ft³ | 416.34 gal | Small pool/tank |
| 1,000 gal | 133.68 ft³ | 832.67 gal | Large storage tank |
| 5,000 gal | 668.40 ft³ | 4,163.37 gal | Small pool |
| 10,000 gal | 1,336.81 ft³ | 8,326.75 gal | Medium pool |
Suggested Tank Dimensions by Capacity
Common tank shapes and dimensions for different gallon capacities.
50 Gallon Tank
Requires 6.68 cubic feet of space
Rectangular
3.5 ft × 2.0 ft × 1.0 ft
Best for: flexible layouts
Cylindrical
1.8 ft (22") diameter × 2.6 ft (31") tall
Best for: vertical tanks
Cube
1.88 ft (23") each side
Best for: compact footprints
100 Gallon Tank
Requires 13.37 cubic feet of space
Rectangular
4.0 ft (48") × 2.0 ft (24") × 1.67 ft (20")
Best for: flexible layouts
Cylindrical
2.0 ft (24") diameter × 4.25 ft (51") tall
Best for: vertical tanks
Cube
2.37 ft (28") each side
Best for: compact footprints
500 Gallon Tank
Requires 66.84 cubic feet of space
Rectangular
6.0 ft (72") × 4.0 ft (48") × 2.8 ft (34")
Best for: flexible layouts
Cylindrical
3.5 ft (42") diameter × 7.0 ft (84") tall
Best for: vertical tanks
Cube
4.06 ft (49") each side
Best for: compact footprints
Space planning note
After converting gallons to ft³, add 10–20% extra space for access, piping, and safety clearance. Example: 500 gallons = 66.8 ft³, plus 20% = ~80 ft³ total space.
Frequently Asked Questions
Answers to common questions about gallons to cubic feet conversions.