Cylinder Volume Calculator

Calculate cylinder volume in cubic feet, gallons, and liters, plus surface area.

By Konstantin Iakovlev · Updated April 2026 · Source: Khan Academy

Volume

141.37 cu ft

Surface Area

150.80 sq ft

Volume Conversions

Cubic Feet141.37
US Gallons1,057.53
Liters4,003.19
Surface Area150.80 sq ft

Use the Cylinder Volume Calculator above to calculate your results. Enter your values and see instant results — all calculations run in your browser.

Disclaimer: This calculator is for informational purposes only and does not constitute tax, financial, or legal advice. Results are estimates based on the information you provide and current rates. Always consult a qualified tax professional or financial advisor for advice specific to your situation.

How It Works

Feed in a radius and a height, and you get back the volume of a cylinder in cubic feet, gallons, and liters, plus its total surface area. Those numbers matter in practical settings: across the 2026 agricultural sector, squeezing a 10% increase in silo capacity out of more accurate volume figures can be worth roughly $5,000 per silo a year in storage costs, and the same math underpins the design of 2026 industrial fluid containers.

Volume comes from the standard expression V = πr²h, with 'r' the radius and 'h' the height. Surface area uses A = 2πrh + 2πr², which adds the curved lateral wall to the two circular end caps. The tool applies these formulas at full precision so the geometry holds up even at large scales.

Before you type anything in, get the radius and height into the same units. Mixing inches with feet is the classic slip, and it throws the result off by a factor of 1728 once you convert to cubic feet. One more thing worth weighing: on thick-walled cylinders the inside and outside dimensions diverge, so measure to the surface that bounds the volume you actually care about.

Example: Calculating Capacity for a 2026 Fuel Storage Tank

  1. 1 A new industrial fuel storage tank, costing $25,000, has an internal diameter of 12 feet and a height of 20 feet. We need to determine its volume in gallons to plan for a fuel delivery costing $3.50 per gallon.
  2. 2 First, calculate the radius: r = diameter / 2 = 12 ft / 2 = 6 ft. Then, apply the volume formula: V = π * (6 ft)² * 20 ft = 3.14159 * 36 sq ft * 20 ft.
  3. 3 This yields a volume of approximately 2261.94 cubic feet. To convert to gallons, we use the conversion factor: 1 cubic foot ≈ 7.48052 gallons. So, 2261.94 cu ft * 7.48052 gal/cu ft.
  4. 4 The tank has a capacity of approximately 16910.74 gallons. At $3.50 per gallon, a full tank would cost $59,187.59 to fill, providing crucial financial planning data for 2026 operations.

Source: Khan Academy · Last updated: April 2026

Frequently Asked Questions

How many gallons does a cylinder hold based on its dimensions?
Volume equals pi times radius squared times height (V = πr²h). For a cylinder with 3-foot radius and 5-foot height, volume is π x 9 x 5 = 141.37 cubic feet.
How many gallons does a cylindrical tank hold?
Calculate the volume in cubic feet (πr²h), then multiply by 7.48 to convert to US gallons. A 2-foot radius, 4-foot tall tank holds about 50.27 cubic feet or 376 gallons.
How do you find the surface area of a cylinder?
Total surface area equals 2πr² + 2πrh (two circles plus the side). For radius 3 and height 5, that is 2π(9) + 2π(15) = 56.55 + 94.25 = 150.80 square units.

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