Home & DIY / Fill it right.
Pool, Spa & Aquarium
Pool, hot tub, and aquarium volume plus stocking — answers the r/aquariums, r/pools, r/hot tubs recurring ‘how many gallons / how many fish’ questions.
4 tools available
Pool Volume Calculator
Compute the gallons in any pool shape (rectangle, oval, round, kidney).
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Hot Tub & Spa Volume Calculator
Estimate the gallons in any hot tub or spa.
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Aquarium Tank Volume Calculator
Compute gallons / liters for any fish tank (rectangle, bowfront, cube, cylinder).
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Aquarium Stocking Calculator
See how many inches of fish your freshwater tank can safely hold.
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