EN

Volume Calculator

This volume calculator works in three steps: pick a shape, enter its dimensions, choose the unit. You get the volume, litres, gallons, surface area and the working.

Example: Shape: Cylinder (round pool, tank) · Round size given as: Radius · Radius r 5 · Height h 20 · Length unit: Centimetres (cm) → Volume: 1,570.8 cm³. Source: Wolfram MathWorld – Cylinder: volume, lateral and surface area. Updated: .

My ToolboxYour inputs are saved in this browser only.

Result

Volume
1,570.8 cm³
In litres
1.5708 L
Surface area
785.398 cm²
Lateral surface
628.319 cm²
Volume in other units
UnitValue
Millilitres (mL)1,570.8
Litres (L = dm³)1.5708
m³0.0015708
cm³1,570.8
US gallons0.41496
UK (imperial) gallons0.345527
Working
  • Volume: V = π · r² · h → V = π · 5² · 20 ≈ 1,570.8 cm³
  • Lateral surface: M = 2 · π · r · h → M = 2 · π · 5 · 20 ≈ 628.319 cm²
  • Surface area: O = 2 · π · r² + M → O = 2 · π · 5² + 628.319 ≈ 785.398 cm²

How it is calculated

The volume of a solid is its base area times its height – for pointed solids such as cones and pyramids, one third of that. A cylinder with a 5 cm radius and 20 cm height holds π × 5² × 20 ≈ 1,571 cm³, or about 1.57 litres.

Volume formulas

If you measured the diameter, switch to “Diameter” and the calculator halves it for you. Using d instead of r is the classic cylinder mistake – it makes the answer four times too large.

Converting volume to litres and gallons

One litre is exactly 1 dm³ = 1,000 cm³, and 1 m³ = 1,000 litres. The calculator also shows millilitres, cubic metres and US gallons (1 gal = 3.785411784 L, NIST) plus UK gallons (4.54609 L). In feet, 1 ft³ = 28.3168 L ≈ 7.48 US gallons. Round pool example: 12 ft across, 3 ft of water → r = 6 ft, V = π × 6² × 3 ≈ 339.3 ft³ ≈ 2,538 US gallons.

Surface area

You also get the surface area – useful for paint, liner or insulation. A cylinder’s surface is two circles plus the lateral surface 2πrh; a cone’s is the base plus πrs with slant height s = √(r² + h²). For a cylinder solved from any two values, use the cylinder calculator.

Limits

The formulas assume ideal shapes. Real tanks have wall thickness, domed bottoms or slopes – measure the inside and add up simple parts. To turn volume into mass, use the density calculator; to add several parts, the calculator.

Frequently asked questions

How do you calculate the volume of a cylinder?

Base area times height: V = πr²h. For a 5 cm radius and 20 cm height: 3.14159 × 25 × 20 ≈ 1,570.8 cm³ ≈ 1.57 litres. From the diameter: V = π(d/2)²h.

How do I convert cubic feet to gallons?

Multiply by 7.48052: 1 ft³ = 28.3168 litres = 7.48 US gallons. A 10 ft³ tank holds about 74.8 gallons.

How do I find the volume of a rectangle box?

Length × width × height. All three must be in the same unit – convert first if needed (e.g. 1.2 m = 120 cm). 50 × 40 × 30 cm = 60,000 cm³ = 60 litres.

How many litres are in a cubic metre?

Exactly 1,000 litres. One litre equals one cubic decimetre (10 cm × 10 cm × 10 cm).

What is the formula for the volume of a sphere?

V = 4/3 πr³. A sphere with a 10 cm radius holds 4/3 × π × 1,000 ≈ 4,188.8 cm³, just under 4.19 litres.

Sources and legal basis

As of:

Related tools