Aquarium Weight Calculator
The aquarium weight calculator estimates how much your tank weighs when filled. Enter your water volume to get the weight of the water plus an approximate total filled weight including the tank, rock and substrate. It’s an essential check before you set up a new build on a stand, floor or piece of furniture.
Water is heavier than most people expect at 8.34 pounds per gallon, and a filled reef system typically runs closer to 10 to 11 pounds per gallon once glass, rock and sand are added. Confirm your floor and stand can safely carry the load, especially for tanks of 75 gallons or more.
Formula: Water weight (lb) = gallons × 8.34
Frequently Asked Questions
How much does a filled aquarium weigh?
Water weighs about 8.34 pounds per gallon, so the water alone in a 55 gallon tank is about 460 pounds. Add the tank, rock and substrate and the real filled weight is higher, often around 10 to 11 pounds per gallon. Enter your volume above for an estimate.
Can my floor hold a fish tank?
Most tanks up to about 55 gallons are fine on a solid floor near a load-bearing wall. Larger tanks of 75 gallons and up concentrate a lot of weight, so place them over floor joists, ideally perpendicular to them, and consult a professional if you are unsure. A 180 gallon system can exceed a ton fully set up.
Does substrate add much weight?
Yes. Sand and gravel are dense, adding roughly 85 to 105 pounds per cubic foot. A few inches across a large footprint can add a hundred pounds or more. Use our substrate calculator to estimate it, then add it in the field above.
