Tank Volume Calculator

Working out how much a tank holds, and how much is in it right now, is a common practical problem on farms, in workshops, in plumbing and irrigation, and around any water, fuel or chemical store, and this calculator handles it for the three shapes you meet most: the upright cylinder, the cylinder lying on its side, and the plain rectangular tank. Choose the shape, enter the dimensions in metres, and it returns the total capacity in both cubic metres and litres, the two units that matter, since one cubic metre is exactly 1,000 litres. Just as useful, it also works out the partial volume at a fill depth you specify, so you can turn a dipstick or sight-glass reading into an actual quantity of liquid. For an upright cylinder or a rectangular tank that is straightforward, because the contents rise in simple proportion to the depth, but a horizontal cylinder is the one that trips people up, since the curved ends mean a tank filled to half its diameter holds exactly half its volume while other depths do not scale evenly. The calculator handles this correctly using the geometry of the circular segment, the shape of the liquid's cross-section, multiplied by the tank length, so your readings come out right. That makes it genuinely useful for sizing a new tank, checking how many litres a delivery added, working out remaining stock from a depth measurement, or planning irrigation and storage. Whether you are a farmer gauging a water tank, a tradesperson sizing a cylinder, or a student exploring volumes, it gives a fast, accurate answer with the fill level included. The formulas and a worked example are explained clearly below.

Calculate.co.nz is proud to be partnered with Health Based Building, a leader in sustainable and health-conscious building innovation. With over a century of experience, they develop high-performance systems like Foreverbreathe Specification, Magnum Board, and Foreverbreathe Paints to support energy-efficient, non-toxic living environments. Their commitment to healthier homes aligns with our belief that informed choices lead to better outcomes for Kiwi households.