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Volume of a barrel calculator

Enter the dimensions of a barrel and read off its volume and surface area. Volumes convert to litres and gallons with the unit selector.

Volume
55.292 031m³
≈ Rounded Volume of a barrel
Surface area
62.831 853
Show the working
  1. Radius at the bulge = 2
  2. Radius at the ends = 1.6
  3. Height = 5
  4. Volume = pi * 5 / 3 * (2*2^2 + 1.6^2) = 55.292
  5. Surface area = 2*pi*2*5 = 62.8319

Values are shown to six significant figures here; the arithmetic itself runs on exact fractions and is only rounded where a number is printed.

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    The formula

    • Kepler's barrel rule: volume = (pi h / 12)(2 D^2 + d^2) with D the bulge diameter and d the end diameter

    Kepler derived this rule in 1615 after suspecting a wine merchant of short measure. It is exact for a parabolic bulge.

    Switch the volume unit to litres or US gallons to read the capacity directly.

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