MEASURE FIRST · PLAN CALMLY
Know what
the tank holds.
Estimate capacity, filled weight and a water change from the dimensions you can measure. Clear inputs, visible assumptions.
Open the tank tools ↓◁◉
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measure inside · before substrate01 / TANK VOLUME
Start with the inside dimensions.
Choose the shape and measurement system. Results are estimates.
YOUR TANK NOTE
Weight reminderWater weighs about 8.33 lb per U.S. gallon (about 1 kg per liter). Glass, substrate, stand, and rocks add more. Confirm floor and stand capacity independently.
02 / THE ASSUMPTIONS
Useful estimates.
No false precision.
Rectangular volume uses the inside length × width × height. Bow-front is a straight-front rectangle plus a half-ellipse approximation; real curve shapes vary. Displacement subtracts a user-entered share of gross volume. Filled weight counts water only.
The water-change result is the chosen percentage of estimated water volume. It does not prescribe husbandry or dosing. Always follow product labels and species-appropriate care guidance.