Aquarium Volume Calculator
Updated Formulas shown
Gallons = L × W × H in inches ÷ 231. A 48 × 13 × 21 in tank holds about 56.7 gallons and weighs roughly 473 lb with water alone.
Tank volume
56.7 gal
215 liters
- Water weight
- 473 lb
- Realistic water volume (≈ 85%)
- 48.2 gal
Gallons = L × W × H (inches) ÷ 231. Substrate, decor and the gap at the top reduce actual water volume.
Quick reference
| Tank (in) | Gallons | Water weight |
|---|---|---|
| 20 × 10 × 12 | 10.4 | 87 lb |
| 24 × 12 × 16 | 19.9 | 166 lb |
| 30 × 12 × 18 | 28.1 | 234 lb |
| 36 × 18 × 16 | 44.9 | 374 lb |
| 48 × 13 × 21 | 56.7 | 473 lb |
| 48 × 18 × 24 | 89.8 | 749 lb |
| 72 × 18 × 24 | 134.6 | 1,123 lb |
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Frequently asked questions
How much does a 55 gallon aquarium weigh?
Water alone is about 459 lb; with glass, gravel and stand, plan for 600+ lb.
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Estimates only. Check quantities with your supplier or contractor before ordering.