Saltwater Aquarium Calculators and Tools

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Saltwater Aquarium Blog tools

Plan with your tank’s real measurements

Use these calculators to estimate volume, filled weight, sand, and live rock from your measurements. Each result shows the planning assumptions and practical limits that matter.

The calculator math runs in your browser—no account required.

Search the Saltwater Aquarium Library

The answer-first version is being prepared as a separate beta. Until then, this searches the current article library.

Calculator 1

Tank volume

Estimate the nominal volume of a rectangular or circular-arc bow-front aquarium from its inside dimensions.

For a bow front, measure from the straight front chord to the deepest point of the curve.
What this estimate includes

This is geometric volume. Rock, sand, equipment, glass thickness, air space, and displacement reduce the usable water volume. Read more about bow-front aquarium tradeoffs.

Calculator 2

Filled aquarium weight

Add the estimated water weight to the tank, stand, sand, rock, equipment, and other components you enter.

1.025 kg/L is the planning default.
Component weights
Use actual operating water volume so rock and sand displacement are not counted twice.
What this estimate does not decide

The total does not certify your stand, floor, joists, or load path. It gives you a better number to use when those need to be checked separately. See the 40-gallon dimensions and weight guide for a worked example.

Calculator 3

Sand-bed amount

Estimate how much dry aquarium sand to buy from the inside footprint and average bed depth.

Planning assumption: This estimate uses 90 lb/ft³ (about 1.44 kg/L), representative of common dry aragonite reef sand. Actual bag weight varies by product, grain shape and size mix, porosity, packing, and moisture. Check the manufacturer’s coverage guidance when available.

Why is this approximate?

Bulk density is the weight of substrate in a given bed volume, including the spaces between grains. It is not particle size alone: composition, grain porosity and shape, the mix of sizes, packing, moisture, slopes, and rock displacement can all change the amount you need.

Calculator 4

Live-rock planner

Choose one of five aquascape amounts and see a shopping estimate for your display. This does not determine filtration capacity, cycle completion, livestock capacity, habitat suitability, or aquascape stability.

Use the display’s nominal or estimated pre-rock volume—not the smaller post-rock operating-water volume.
Typical · 1.00 lb/US galLess rock → more rock
The upper stop is a very rock-heavy layout, not a preferred target. Porous rock fills more space per pound than dense rock.
How to use the result

Use the estimate for shopping and layout planning—not as a biological-filtration requirement. Prioritize stable structures, water flow, swimming room, maintenance access, future coral growth, and the habitat your animals need.

More aquarium tools

Calcium dose calculator

The product-label calculator remains behind its additional safety and release review.

Under review

Live aquarium simulator

The simulator will join this hub after its own validation and release decision.

In development

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