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Aquarium calculators
Free, instant and private: every calculation runs in your browser. Start with the volume, then size everything else from it.
Tank volume
- Rectangular tank volumeGallons, liters and water weight from length, width and height, with standard tank sizes built in.
- Bow-front tank volumeMeasure the length, the depth at the ends and at the center of the bow, and the height. The bow is calculated as a true circular arc.
- Cylinder tank volumeFor round column tanks, bowls with straight sides and acrylic cylinders: enter the diameter and the height.
- Hexagon tank volumeRegular hexagon tanks have six equal panels. Measure the width of one panel and the height.
Equipment, water and stocking
- Weight calculatorAdd up water, glass, wet substrate, rock and the stand to see what a set-up tank really weighs — and how hard it presses on your floor.
- Substrate calculatorEnter the inside footprint and the depth you want at the front and back. The calculator returns weight, volume and the number of bags.
- Heater size calculatorHeater size depends on how far the water must be lifted above the coldest room temperature, not just on gallons.
- Filter flow rate calculatorTurnover — how many times per hour the filter moves the tank’s volume — is the number that matters. Here is the flow to aim for and the filter rating to buy.
- Water change calculatorEvery water change removes the same share of nitrate. Enter your test results to see how many changes it takes to reach a target and where a weekly routine settles.
- Dosing calculatorLabels give a dose per 10, 40 or 50 gallons; your tank is something else. Enter the label dose and the volume you are treating.
- Glass thickness calculatorPlanning a DIY or custom tank? Enter the size to estimate how thick the front, end and bottom glass should be — then have a glass supplier or engineer check it.
- Stocking calculatorAdd the fish you keep or plan to keep. The calculator estimates bioload against your filtration and flags tank size, group size and temperature problems.