9 free calculators
Aquatics calculators
Fish-keeping starts with knowing how much water is in the tank. These calculators turn tank measurements into litres and gallons and work out how much water a percentage water change replaces. They are arithmetic tools: species needs come from species-specific advice.
- Aquarium Volume CalculatorWork out your fish tank's volume in litres and gallons from its dimensions.
- Aquarium Water Change CalculatorWork out how much water to replace for the percentage change you choose.
- Aquarium Water Weight CalculatorWork out how much the water in a fish tank weighs so you can check your stand and floor.
- Pond Volume CalculatorEstimate a garden pond's volume in litres and gallons from its length, width and average depth.
- Pet Temperature ConverterConvert aquarium, room and water temperatures between Celsius and Fahrenheit.
- Aquarium Substrate Volume CalculatorWork out how many litres of gravel or sand you need for a layer of a chosen depth.
- Aquarium Filter Turnover CalculatorSee how many times per hour your pump or filter moves the whole tank volume.
- Pond Pump Turnover CalculatorSee how often your pond pump moves the whole pond volume, in times per hour and minutes per cycle.
- Pond Liner Size CalculatorWork out the liner size for a pond from its length, width, depth and the edge overlap.
Every calculator shows its formula and sources, works in metric and imperial units, and gives estimates only. Read how we build and review them in our editorial policy and formulas & sources.