Tool
Tank weight calculator
Water is heavy. Check what your filled tank weighs before it goes on a shelf, floor or upstairs room.
Your result
About 59 kg of water and substrate
≈ 130 lb, or about 328 kg per m². Add the weight of the glass, cabinet and décor on top.
What this calculator does
A litre of water weighs about 1 kg, so even a modest tank adds a lot of mass to whatever it stands on. This tool estimates the weight of the water and substrate from your dimensions, then expresses it as a total and as a load per square metre, so you can judge whether a floor, shelf or cabinet is suitable.
When to use it
- Placing a tank on an upstairs floor or suspended timber.
- Checking a shelf or cabinet can take the load.
- Choosing a stand that matches the filled weight.
How to use it
- Measure inside dimensions and estimate your substrate depth.
- Read the water + substrate weight.
- Add the tank, stand and décor. Glass, rocks and wood can add a lot, and the stand itself has weight.
Worked example
A 60 × 45 × 45 cm tank with 5 cm of substrate holds around 108 litres of water plus about 20 kg of gravel — roughly 128 kg before you count the glass and cabinet. On a small footprint that is a heavy point load, not just a gentle weight.
Limitations
- It excludes the tank and stand. Add those for the true load; a large glass tank can weigh 30–60 kg empty.
- Point loads matter. Weight concentrated on small feet is harder on floors than the same weight spread over a base.
- It is not structural advice. For large tanks on upper floors, especially timber, consult a professional.
Frequently asked questions
How much does a 100-litre tank weigh?
The water alone is about 100 kg. Add substrate, glass and a stand and the full setup is commonly 150 kg or more.
Can an upstairs floor take a big tank?
Concrete floors usually cope; suspended timber floors need care and often reinforcement. For anything large, get it checked.
Does substrate really weigh much?
Gravel is heavier than water — around 1.5 kg per litre — so a deep bed adds a meaningful amount on top of the water.
Related guides
Sources and research notes
Water is taken as 1 kg per litre; aquarium gravel is approximated at 1.5 kg per litre. These give an estimate, not an exact figure.