Aquarium Volume Calculator Guide
An aquarium volume calculator converts tank dimensions into water volume and weight so you can size filters, heaters, and stands correctly. Choose a shape (rectangle, cylinder, hex, bowfront, etc.), enter dimensions, and get liters, US/UK gallons, and estimated water weight.
What is Aquarium Volume Calculator?
The aquarium volume calculator helps aquarists estimate real‑world water volume by considering shape and filled depth. It’s useful for dosing medications, setting heater wattage, and checking whether furniture or floors can support the system.
How to Use the Aquarium Volume Calculator
- Select tank shape: rectangle/cube, cylinder, bowfront/hex, etc.
- Enter dimensions and fill height (the waterline below the rim).
- Compute volume in liters, US gallons, and UK gallons.
- See water weight using 8.34 lb/US‑gal (≈1 kg/L) and add a margin for glass, substrate, and decor.
- Save the result for maintenance and dosing notes.
Formulas & Methods
- Rectangle/cube:
V = L × W × H - Cylinder:
V = πr² × H - Hex/prism approximations: decompose into rectangles/triangles or use shape‑specific formulas.
- Unit conversions:
1 cubic ft ≈ 7.48 US gal;1 L ≈ 0.26417 US gal. - Weight:
Weight_water ≈ Volume(US gal) × 8.34 lb(water only).
Assumptions & limitations
- Displacement from substrate/decor reduces water volume.
- Shapes with thick walls or braces reduce internal space slightly.
- Saltwater density is higher; weight estimates are conservative.
Examples
Example A — Standard rectangle
L=36 in, W=12 in, H=16 in, filled to 15 in.
Volume = (36×12×15)/231 ≈ 28.0 US gal (231 in³ per US gallon).
Water weight ≈ 28.0 × 8.34 ≈ 234 lb (water only).
Example B — Cylinder
Diameter 20 in → r=10 in, height 24 in, filled to 22 in.
Volume = π × 10² × 22 / 231 ≈ 29.9 US gal.
Weight ≈ 29.9 × 8.34 ≈ 249 lb.
| Conversion | Value | |---|---| | 1 cubic foot → US gal | 7.48 | | 1 liter → US gal | 0.26417 | | 1 US gal water weight | 8.34 lb |
Pro Tips & Best Practices
- Measure internal dimensions (glass thickness reduces internal volume).
- Use filled depth, not tank height, for dosing and heater sizing.
- Add 10–15% for rock/sand weight when assessing stand/floor loads.
- Quarantine tanks are smaller—recalculate doses separately.
- Keep a log of water changes using exact volumes for stability.
Related Calculators
FAQ
Q: How is aquarium water volume calculated?
A: By applying geometric volume formulas for the chosen tank shape and converting to gallons/liters.
Q: How many gallons are in a cubic foot of water?
A: About 7.48 US gallons per cubic foot (8.34 lb per US gallon).
Q: Should I include substrate and decorations?
A: For water volume, subtract displacement from rocks, substrate, and equipment; the calculator estimates filled depth.
Q: Why is filled depth important?
A: Most tanks aren’t filled to the brim; using fill height gives a more accurate water volume and dosing basis.
Q: Is the weight estimate safe for furniture?
A: Use it as a screening value; always check manufacturer load ratings and consider dynamic loads.
Call to Action
Enter your tank’s dimensions and fill height above to get precise volume and weight—then size your equipment with confidence.