Tank weight calculator
Total weight on your floor: water, glass, substrate, hardscape, and stand. For anyone worried about putting a tank upstairs.
| Water | -- |
| Glass | -- |
| Substrate | -- |
| Hardscape | -- |
| Equipment (~) | -- |
| Stand | -- |
Why this matters
Water weighs about 1 kg per liter. A 200 L tank holds 200 kg of water before you add glass, substrate, rocks, and the stand. That's roughly 300 kg (660 lb) sitting on a footprint smaller than a desk.
A 75 L tank on a standard cabinet is fine almost everywhere. A 400 L tank on a second floor apartment needs thought about where it goes. A 1000 L tank needs someone to look at the floor.
What this calculates
Enter your tank dimensions and what's going in it. The calculator estimates the total weight, breaks it down by water, glass, substrate, hardscape, equipment, and stand, and gives the load per metre of stand length. The verdict goes by total weight.
Why not weight per square metre of footprint? Because a tank on a stand isn't a uniform load spread over a floor, it's a line load that crosses one or more joists. Dividing by the footprint makes a small cube fail the same test a fridge would pass. The total, and how many joists the stand crosses, is what a floor cares about.
The glass weight estimate assumes standard soda-lime aquarium glass at 2.5 g per cubic centimeter. If your tank uses low-iron glass or acrylic, the weight is slightly different but not enough to change the floor-load verdict.
Substrate densities
Wet substrate weighs more than the bag label suggests. Sand settles and packs; aquasoil absorbs water and gets heavier over the first few weeks. The densities here are post-settling wet weights, not dry bag weights.
When to worry
Under 300 kg all up: fine on any sound floor, upstairs included. That covers most tanks up to about 200 L with a cabinet under them. A loaded bookcase or a big fridge weighs the same.
300 to 700 kg: put it against a load-bearing wall, with the stand running across the joists rather than along one, so several joists share it. Joists are strongest near the walls they bear on and weakest mid-span. On a concrete slab or a ground floor over a proper subfloor there's nothing to think about.
Over 700 kg: get the floor checked before you fill it, unless it's on a slab. This is 500 L and up. An hour of a builder's or engineer's time is cheap, and the usual fix (a post underneath or a doubled joist) is a small job compared to the alternative.
Related tools
- Tank volume - Start with tank dimensions.
- Substrate volume - Estimate substrate depth and weight.