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Aquarium Sand Calculator

Calculate substrate pounds (lbs), kilograms, and 20-lb / 5-lb bag requirements for standard aquarium tank sizes or custom glass dimensions.

Substrate Needed

Real-Time
Sand Weight Required
0 lbs
0 kg
20 lb Substrate Bags
0 Bags
Standard pet store size
5 lb Substrate Bags
0 Bags
For nano tanks
Bed Volume
0.00 CFT
Total displacement
Visual Engineering

Fish Tank Substrate Bed & Plants

Glass aquarium cross-section showing sloped underwater sand bed for planted and reef tanks.

SUBSTRATE BED (1" - 3" DEPTH) AQUARIUM MATH • Substrate (lbs) = (L" × W" × D") / 17.5 • Community tank: 1" to 1.5" depth • Planted tank: 2" to 3" depth • Cichlid diggers: 2" fine silica

Fish Tank Substrate Bed & Plants

Glass aquarium cross-section showing sloped underwater sand bed for planted and reef tanks.

Mathematical Theory

Engineering Calculations & Formulas

Mathematical formulas and engineering constants powering this calculator.

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Substrate Weight Formula

Standard aquarium hobbyist formula based on tank footprint dimensions.

Substrate (lbs) = (Tank Length in × Tank Width in × Depth in) / 17.5
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Planted Tank Bed Volume

Required substrate volume supporting aquatic plant root development.

Plant Substrate = 2.0 to 3.0 inches depth (1.5–2 lbs per gallon)
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Aquarium Bag Count (20 lb)

Pre-bagged retail aquarium sand bag counts (10 lb / 20 lb bags).

20lb Bags = ⌈ Substrate lbs / 20 ⌉