Comprehensive Volume Calculator | Cube, Cylinder, Cone, and Sphere Volumes

What this calculator does and when to use it

This tool finds the volume of four common solids — a cube, cylinder, cone, or sphere — from a small number of linear measurements, then converts that volume into liters, US gallons, and cubic feet automatically. Volume calculations come up constantly outside a classroom: figuring out how much water a tank holds, how much concrete a cylindrical footing needs, how much soil fills a planter, or how much a shipping container can carry.

Pick the shape that matches what you're measuring, choose the unit your measurements are already in (millimeters through feet), and enter the dimensions. Because the calculator re-expresses the result in three different volume units at once, it's also a fast way to sanity-check a supplier's spec sheet or convert between metric and US customary volumes without hunting for a separate conversion factor.

The formulas

Each shape uses a standard geometric volume formula, applied to whatever unit you selected (so results are in that unit cubed until converted):

Cube: V = s³, where s is the side length.
Cylinder: V = πr²h, where r is the base radius and h is the height.
Cone: V = (1⁄3)πr²h, where r is the base radius and h is the height — exactly one-third of a cylinder with the same base and height.
Sphere: V = (4⁄3)πr³, where r is the radius.

After computing volume in the input unit, the calculator converts to cubic meters using the unit's length-to-meter factor cubed, then multiplies to get liters (×1000), US gallons (×264.172052), and cubic feet (÷0.0283168466).

Worked example

Take a cylindrical container with radius 5 cm and height 15 cm. Volume = π × 5² × 15 = π × 25 × 15 = 375π ≈ 1,178.097 cm³. Converting: 1,178.097 cm³ = 0.001178097 m³, so that's about 1.178 liters, 0.311 US gallons, and 0.042 cubic feet — matching what the calculator displays for those inputs.

Common mistakes and how to interpret results

Entering diameter instead of radius. The cylinder, cone, and sphere fields all ask for radius, not diameter — using diameter will overstate volume by a factor of 8 for a sphere (since r³ is cubed) or 4 for a cylinder/cone.
Mixing units within one shape. If you measure height in inches but radius in centimeters, convert one of them first — the calculator applies a single selected unit to every dimension for that shape.
Forgetting the cone's one-third factor. A cone is easy to overestimate because it's tempting to compute it like a cylinder; the true volume is exactly a third of a cylinder sharing the same base and height.
Reading the wrong equivalent unit. Double-check whether you need liters, US gallons, or cubic feet — US and Imperial gallons differ, and this calculator reports the US gallon.

Related calculators

Volume unit conversion table

Use this table to convert between common US customary and metric volume units at a glance.

Unit	fl oz	cups	pints	quarts	gallons	liters	mL
1 fl oz	1	0.125	0.0625	0.03125	0.0078	0.02957	29.57
1 cup	8	1	0.5	0.25	0.0625	0.2366	236.6
1 pint	16	2	1	0.5	0.125	0.4732	473.2
1 quart	32	4	2	1	0.25	0.9464	946.4
1 gallon	128	16	8	4	1	3.785	3785
1 liter	33.81	4.227	2.113	1.057	0.264	1	1000
1 mL	0.0338	0.00423	0.00211	0.00106	0.000264	0.001	1

Cooking measurement quick reference

Handy equivalents for US cooking measurements — tablespoons, cups, fluid ounces, and milliliters.

Measurement	Equivalent
1 tablespoon	3 teaspoons = ½ fl oz = 14.8 mL
¼ cup	4 tablespoons = 2 fl oz = 59.1 mL
⅓ cup	5 tbsp + 1 tsp = 78.9 mL
½ cup	8 tablespoons = 4 fl oz = 118.3 mL
¾ cup	12 tablespoons = 6 fl oz = 177.4 mL
1 cup	16 tablespoons = 8 fl oz = 236.6 mL

Liters to gallons conversion table

Quick reference for converting liters (1–20) to both US gallons (1 US gal = 3.785 L) and Imperial gallons (1 imp gal = 4.546 L).

Liters	US Gallons	Imperial Gallons
1 L	0.264 gal	0.220 gal
2 L	0.528 gal	0.440 gal
3 L	0.793 gal	0.660 gal
4 L	1.057 gal	0.880 gal
5 L	1.321 gal	1.100 gal
6 L	1.585 gal	1.320 gal
7 L	1.849 gal	1.540 gal
8 L	2.113 gal	1.760 gal
9 L	2.378 gal	1.980 gal
10 L	2.642 gal	2.200 gal
11 L	2.906 gal	2.420 gal
12 L	3.170 gal	2.641 gal
13 L	3.434 gal	2.861 gal
14 L	3.698 gal	3.081 gal
15 L	3.963 gal	3.301 gal
16 L	4.227 gal	3.521 gal
17 L	4.491 gal	3.741 gal
18 L	4.755 gal	3.961 gal
19 L	5.020 gal	4.181 gal
20 L	5.283 gal	4.402 gal

Frequently Asked Questions

How do I convert diameter to radius for these formulas?

Divide the diameter by 2. If you measured a cylindrical pipe's width as 10 cm across, the radius to enter is 5 cm. Entering the diameter directly instead of the radius will overstate the volume by a factor of 4 for cylinders and cones, and by a factor of 8 for spheres.

Why is a cone's volume exactly one-third of a cylinder's?

This is a geometric identity: for the same base radius and height, a cone's cross-sectional area shrinks linearly from the base to a point, and integrating that shrinking area over the height yields exactly one-third of the constant cross-sectional area of a matching cylinder. It holds for any radius and height, not just specific values.

Why do the liter and gallon figures look like rounded numbers?

The geometric volume in your chosen unit (cm³, in³, etc.) is exact given your inputs, but liters, US gallons, and cubic feet come from conversion factors that don't divide evenly (1 m³ = 264.172052 US gallons, for example). The displayed figures are simply rounded for readability — the underlying conversion is mathematically exact.

Does this calculator use US gallons or Imperial gallons?

US gallons. A US gallon (about 3.785 liters) is smaller than an Imperial gallon (about 4.546 liters) used in the UK and some other countries. To get an Imperial gallon figure, take the liters result and divide by 4.546 instead of using the US gallon value shown.

How many cups are in a gallon?

There are 16 cups in a US gallon. The breakdown follows the US customary chain: 1 gallon = 4 quarts, each quart = 2 pints, each pint = 2 cups — so 4 × 2 × 2 = 16 cups. In metric terms, 1 US gallon ≈ 3,785 mL and 1 cup = 236.6 mL, which confirms 3785 ÷ 236.6 ≈ 16 cups.

How many ml in a cup?

One US customary cup equals exactly 236.588 mL, commonly rounded to 236.6 mL. In many recipe contexts it is approximated as 240 mL for convenience. Note that Australian and Canadian recipes sometimes use a metric cup of 250 mL — if precision matters, check which standard the recipe follows before measuring.

How many liters in a gallon?

One US gallon equals approximately 3.785 liters (the exact value is 3.785411784 L). The Imperial gallon used in the UK is larger at approximately 4.546 liters. To convert: multiply US gallons by 3.785 to get liters, or divide liters by 3.785 to get US gallons. For Imperial gallons, use 4.546 as the factor.

How many tablespoons in a cup?

There are 16 tablespoons in 1 US cup. Each tablespoon is about 14.8 mL, so 16 × 14.8 ≈ 236.8 mL — essentially 1 cup. Common fractions: ¼ cup = 4 tablespoons, ⅓ cup = 5 tablespoons + 1 teaspoon, ½ cup = 8 tablespoons, ¾ cup = 12 tablespoons. One tablespoon is also equal to 3 teaspoons or ½ fluid ounce.

Comprehensive Volume Calculator: Cube, Cylinder, Cone, Sphere | Free Online Tool

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