Aquarium Tank Weight Calculator
Estimate how much a filled aquarium weighs so you can check a stand or floor can take it. Enter the water volume in US gallons, the empty tank weight, and any substrate and rock, then choose fresh or saltwater. The tool returns the water weight and the total in pounds and kilograms. These are guideline figures.
How to use the aquarium tank weight calculator
- Enter the water volume in US gallons and choose fresh or saltwater.
- Add the empty tank weight, plus any substrate and rock in pounds.
- Read the water weight and the total filled weight in pounds and kilograms.
Examples
55 gallon freshwater build
55 gallons, empty tank 78 lb, substrate 50 lb, rock 20 lb
Water about 459 lb, total about 607 lb (about 275 kg)
55 gallons of saltwater
55 gallons, saltwater, no extras
Water about 470.25 lb at 8.55 lb per gallon
Frequently asked questions
How much does a filled aquarium weigh?
A rough rule is about 8.35 lb per US gallon for fresh water, or about 8.55 lb per gallon for saltwater, before you add the tank, substrate and rock. A 55 gallon freshwater build with a glass tank, gravel and rock can easily total around 600 lb.
Why is saltwater heavier than fresh water?
Dissolved salt makes the water denser. Fresh water is about 8.345 lb per US gallon, while saltwater at typical reef salinity is closer to 8.55 lb per gallon. The tool switches between the two figures when you toggle saltwater on.
How are pounds converted to kilograms here?
The tool uses the exact factor of 1 pound to 0.45359237 kilograms. So a 607 lb filled tank is about 275 kg. Use the kilogram figure if your furniture or floor load ratings are given in metric units.
Can my floor and stand take the weight?
Large tanks concentrate a lot of weight on a small footprint, so use a stand rated for the load and place it over a load bearing wall or joists where possible. If you are unsure about an upper floor, ask a qualified builder before filling the tank.
How accurate is this estimate?
It is a guideline only. Glass thickness, the frame, lid, sump, equipment and the exact salinity all shift the real weight, and substrate and rock weights vary by material. Add a comfortable safety margin rather than sizing a stand to the exact number.
Related tools
Aquarium Stocking Calculator
Estimate how many inches of fish your tank holds or what tank size your fish need. Uses the inch per gallon guideline for fresh or saltwater.
Aquarium Heater Wattage Calculator
Estimate the heater wattage your fish tank needs from its size and how far above room temperature you heat. Uses the watts per gallon guideline.
Aquarium Water Change Calculator
Work out how much water to swap in a partial aquarium water change. Enter your tank size and change percent to get gallons and liters to replace.
Aquarium Salt Mix Calculator
Estimate how much marine salt to mix for a target salinity. Enter gallons and a specific gravity to get grams, kilograms and pounds of salt.
Cat Food Portion Calculator
Estimate how many calories and how much food your cat needs daily. Enter weight, activity factor and food calories per cup or can for a portion.
Dog Food Portion Calculator
Estimate how many calories and cups of food your dog needs each day. Enter weight, activity factor and food calories per cup to get a daily portion.