Aquarium Tank Volume
Calculator
Results
- Gross volume (L)
- 216
- Volume taken by the substrate (L)
- 24
- Net water volume (L)
- 192
- Net water volume (US gallons)
- 50.721034
- Mass of water (kg)
- 192
Pool and aquarium results
| Gross volume (L) | 216 |
| Volume taken by the substrate (L) | 24 |
| Net water volume (L) | 192 |
| Net water volume (US gallons) | 50.721034 |
| Mass of water (kg) | 192 |
formula-map diagram
- Gross volume (L)
- 216
- Volume taken by the substrate (L)
- 24
- Net water volume (L)
- 192
- Net water volume (US gallons)
- 50.721034
- Mass of water (kg)
- 192
Pool and aquarium relationship
Formula
V = L × W × H − (L × W × substrate depth)= 216
Note
This is a simplified model: it applies a standard geometric or physical formula to the numbers you entered. Volumes assume a regular shape and an even average depth, and the kidney shape uses the common 0.45 × (A + B) × L area approximation. Chemical doses convert a target change into a product mass using the strength or label dose you enter, because the amount of active ingredient varies from product to product; they ignore pH, temperature, buffering, sunlight, bather load and existing chemical interactions. Heating uses Q = m × c × ΔT with c = 4186 J/kg·K and ignores heat losses to air, ground and evaporation; evaporation and cover figures use the rate you enter, not local weather. Aquarium stocking by surface area is a rule of thumb, not a biological limit. Always follow the product label and test the water before and after dosing, and consult a pool or aquarium professional for anything you are unsure about.
More in Pool and aquarium
See all →Frequently asked questions
How is aquarium tank volume calculated, and why does it differ from the label on the box?+
Volume is length times width times height, converted to gallons or liters, but manufacturers' labeled sizes are rounded to a nominal figure (a '20-gallon' tank often holds closer to 18-19 gallons of actual water). The calculator uses your real measurements, so trust it over the box label for dosing and stocking decisions.
Should I use the full tank height or subtract for the substrate and water line?+
Use the height of the water column itself, not the glass height: subtract substrate depth and leave room for any gap below the rim where you keep the water level. Most tanks are filled to about 1-2 inches below the rim, and that's the number to use.
Why does the calculator matter for both fish stocking and medication dosing?+
Both rely on accurate water volume: stocking guidelines are expressed per gallon or liter of water, and medication doses are calculated per unit of volume, so an inflated volume figure leads to under-medicating, which can let disease persist or breed resistance. Getting this number right is one of the highest-leverage inputs in aquarium keeping.
Does decor, substrate, and equipment reduce the actual water volume?+
Yes — substrate, rocks, driftwood, and internal filters all displace water, typically reducing true water volume by 5-10% in a heavily decorated tank. The calculator gives you the gross tank volume; for precise dosing in a densely decorated tank, reduce the result by that margin or measure displaced water directly.
My tank isn't a rectangle — it's a bow-front or hexagon. How much error does that introduce?+
Bow-front tanks hold noticeably more than a straight-sided box calculation suggests, sometimes 5-8% more, because of the curved front panel; hexagonal tanks are close to a rectangular calculation using their overall footprint. For a hexagon, using length times width as if it were a rectangle then multiplying by roughly 0.65-0.7 gets a closer estimate.