How do I find the surface area of a cylinder?

Total surface area = 2πr² + 2πrh. This includes both circular bases (2πr²) and the lateral (side) surface (2πrh). Lateral area only = 2πrh.

How do I find the radius from the diameter?

Radius = Diameter ÷ 2. If you know the circumference, radius = Circumference ÷ (2π). The calculator accepts either radius or diameter — select which one you know.

Cylinder Volume Calculator – Volume & Surface Area

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Cylinder Volume FAQ

Common questions about cylinder measurements and formulas.

What is the formula for the volume of a cylinder?

V = π × r² × h where r = radius and h = height. If you have the diameter, r = d ÷ 2. Example: r = 5 cm, h = 10 cm → V = π × 25 × 10 = 250π ≈ 785.4 cm³.

How do I calculate the surface area of a cylinder?

Total surface area = 2πr² + 2πrh. The 2πr² covers both circular bases, and 2πrh is the lateral (curved side) area. If it's an open cylinder (no lids), use just 2πrh.

What is the volume of a cylinder with radius 3 and height 5?

V = π × 3² × 5 = π × 9 × 5 = 45π ≈ 141.37 cubic units.

How do I convert cubic inches to gallons?

1 US gallon = 231 cubic inches. Divide your volume (in³) by 231. Example: a cylinder that holds 462 in³ = 462 ÷ 231 = 2 gallons. The calculator shows this conversion automatically when inches are selected.

How do I find the height if I know the volume and radius?

Rearrange the formula: h = V ÷ (π × r²). Example: volume = 500 cm³, radius = 4 cm → h = 500 ÷ (π × 16) = 500 ÷ 50.27 ≈ 9.95 cm.