Calculators
Volume Calculator
Choose a shape, enter its dimensions and get the volume with the worked formula, in cubic meters, liters, cubic feet, cubic yards and US or UK gallons.
V = l × w × h
Calculated on your device — nothing is sent anywhere. Sketches are schematic.
Works in your browser. No account needed.
Frequently asked questions
How do I calculate how many liters or gallons a tank holds?
Work out the volume in cubic units, then convert: 1 m³ is 1,000 liters, 1 ft³ is about 7.48 US gallons, and 1 US gallon is exactly 231 cubic inches (3.785411784 L). Choose the tank shape, enter the inside dimensions, and the calculator shows the capacity in liters, US gallons and UK gallons at once.
How is the liquid in a horizontal cylindrical tank calculated?
The wet cross-section is a circular segment. For radius r and liquid depth f its area is r² × arccos((r − f)/r) − (r − f) × √(2rf − f²); multiplying by the tank length gives the liquid volume. It is not proportional to depth — a tank filled to a quarter of its diameter holds only about 20% of its capacity.
What is the difference between US and UK gallons?
A US gallon is 3.785411784 liters (231 cubic inches), while a UK imperial gallon is 4.54609 liters — about 20% larger. Check which one a spec sheet or recipe means; the calculator shows both side by side so you can compare.
What are the formulas for a cone, sphere and pyramid?
A cone is ⅓ × π × r² × h, a sphere is ⁴⁄₃ × π × r³, a hemisphere is half that, and a pyramid is ⅓ × base area × height. A cone or pyramid holds exactly one third of the cylinder or box with the same base and height.
Should I measure inside or outside dimensions?
For how much a container holds, measure the inside. For how much material a solid object contains, measure the outside. With thick-walled tanks, planters or pools the difference can be large, so use inside measurements whenever you want capacity.
Is anything uploaded?
No. The calculator runs entirely in your browser and nothing you type leaves your device. Default units follow your browser’s language — inches and US gallons in the US, centimeters and liters elsewhere — and can be changed at any time.
About this tool
This volume calculator handles thirteen solids: cube (V = a³), box or rectangular prism (V = l × w × h), cylinder (V = πr²h), cone (V = ⅓πr²h), frustum or truncated cone (V = ⅓πh(R² + Rr + r²), handy for buckets and planters), sphere (V = ⁴⁄₃πr³), hemisphere (V = ⅔πr³), rectangular pyramid (V = ⅓lwh), triangular prism, capsule, and three tank shapes. Each result repeats the formula with your numbers substituted, so you can check the working or reuse it in a report.
Lengths can be entered in millimeters, centimeters, meters, kilometers, inches, feet, yards or miles, and the volume is shown in cubic centimeters (milliliters), liters, cubic meters, cubic inches, cubic feet, cubic yards, US gallons, UK gallons, US quarts, US fluid ounces, oil barrels and acre-feet. All factors are exact definitions: an inch is 25.4 mm, so a cubic foot is 28.316846592 L; a US gallon is 231 in³; a UK gallon is 4.54609 L; an oil barrel is 42 US gallons.
The tank modes answer the practical question of how much liquid is in a partly filled tank. A vertical cylinder or rectangular tank fills in proportion to depth, but a horizontal cylinder does not — the calculator uses the exact circular-segment formula, so a reading from a dipstick converts correctly to liters or gallons. It also shows the percentage full and how much more the tank can take.
For concrete, soil, mulch and other bulk materials, cubic yards and cubic meters are the usual ordering units; the concrete calculator adds waste allowance and bag counts on top of the same geometry. For any volume, measure carefully and keep all dimensions in one unit: because volume multiplies three lengths, a 5% error in each measurement grows to roughly 16% in the result.
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