Estimate a stocked fish tank's total filled weight — glass, water, substrate and rock — and the floor load, to check stand and floor limits before setup.
Enter fill volume, substrate, rock and glass dimensions to estimate total weight and floor load.
Tank panel dimensions and pane thickness for the glass estimate.
About this tool
The Aquarium Filled Weight Calculator is a free, in-browser tool that estimates what a fully set-up fish tank weighs so you can check whether a stand, cabinet or floor can carry it. It sums four parts — water, substrate, rock/hardscape and the glass (or acrylic) itself — and reports the total in kilograms and pounds, plus the point load spread over the tank's footprint. All math runs locally in your browser.
Water weight is fill volume × 1.0 kg/L for freshwater or × 1.025 for saltwater (about 8.34 and 8.55 lb per US gallon). Substrate weight is its volume in liters × a bulk density (gravel 1.6, sand 1.5, aquasoil 0.8, crushed coral 1.4 kg/L). Rock is entered directly in kilograms. The glass estimate sums the panel areas — bottom L × W, two sides W × H, and front + back L × H — multiplied by thickness and material density (glass 2.5, acrylic 1.18 g/cm³). The total is divided by the footprint to give a load in lb/ft² and kg/m² as an informational floor check.
As a worked example, a 90 × 45 × 50 cm glass tank (10 mm panels) filled with about 200 L of freshwater, 20 L of gravel and 10 kg of rock weighs roughly 286 kg (about 630 lb): 200 kg water + 32 kg substrate + 10 kg rock + about 44 kg of glass. Concentrated over a 0.405 m² footprint that is around 705 kg/m². Large tanks can exceed common residential floor guidance, so place big tanks near load-bearing walls and consider a professional assessment.
Frequently asked questions
How much does a filled aquarium weigh?
Add water (fill volume × 1.0 kg/L fresh or 1.025 saltwater), substrate (volume × bulk density), rock, and the glass panels (area × thickness × 2.5 g/cm³). Water alone is about 8.34 lb per US gallon freshwater, so weight adds up fast — a 200 L tank setup is roughly 286 kg.
How is the glass weight estimated?
It sums the six panel areas — bottom (L × W), two sides (W × H) and front + back (L × H) — multiplies by the pane thickness and by the material density (2.5 g/cm³ for glass, 1.18 for acrylic). If you know the empty-tank weight from the maker, that value is more exact.
Will my floor hold a large aquarium?
The tool divides total weight by the footprint to show a load in lb/ft² and kg/m². Big tanks can exceed typical residential floor guidance (~40 lb/ft² live load), so place them near load-bearing walls, spread the load with a proper stand, and get a professional check for very large tanks.
Does saltwater weigh more than freshwater?
Yes. Saltwater has a density around 1.025 kg/L versus 1.0 for freshwater, so it is about 2.5% heavier — roughly 8.55 versus 8.34 lb per US gallon. The calculator applies the correct density when you pick freshwater or saltwater.