Build a component-by-component load estimate for the full installation.
This is a component sum, not a structural-safety verdict.
Water is usually the largest single component, but it is not the whole load. A useful household estimate adds the tank, stand, substrate, rocks, equipment, external filter water and anything permanently stored in the cabinet.
A setup with 180 litres of freshwater, a 30 kg empty aquarium, 20 kg of substrate, 5 kg of rock and a 35 kg cabinet totals roughly 270 kg before other equipment. That is materially different from calling it a “180 kg tank”.
Total mass is one part of the support question; footprint and the way the stand transfers that load also matter.
This calculator does not decide whether a floor, joist system or cabinet is structurally adequate. Construction type, span, load path, stand footprint and local building details matter. If there is doubt, use appropriate structural advice rather than a web calculator.
For rough freshwater planning, treating one litre as about one kilogram is a practical approximation. Saltwater is denser, and a marine system may also include a sump, extra rock and additional equipment. Enter the masses you actually know instead of forcing every setup through one hidden assumption.
The water is usually the largest single component, but it is not the whole installation. A useful estimate adds each known mass separately: water, empty aquarium, stand or cabinet, substrate, rocks or wood, external equipment, and anything permanently stored in the cabinet.
| Component | Best source for the number |
|---|---|
| Water | Actual litres from the volume calculator |
| Empty aquarium | Manufacturer specification where available |
| Substrate | Bag weight or product specification |
| Rock / wood | Measured or weighed estimate |
| Cabinet / stand | Manufacturer specification |
| External filter / sump | Equipment plus contained water |
A calculator can estimate kilograms; it cannot inspect the building. Floor construction, joist direction and span, the footprint of the stand, where the load sits in the room and how the cabinet transfers that load all matter. If a large setup raises doubt, seek appropriate structural advice rather than treating a web calculator as an engineering assessment.
That boundary is intentional. The useful job of this page is to stop the common under-estimate of counting the water and forgetting everything else.