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Water Tank Calculator.

Calculate cylindrical or rectangular tank volume with explicit dimensions and unit conversion.

On-device calculationNo signup
01

Set your values

Results update as you type.

cubicFeet: 12,566.37

cubicFeet

0.00
cubicMeters: 355.84

cubicMeters

0.00
liters: 355,839.99

liters

0.00
gallons: 94,002.98

gallons

0.00

Outputs use your entered dimensions and an explicit waste percentage; no material density is inferred.

FAQs

Does usable capacity equal geometric capacity?

No. The result is geometric volume; fittings, freeboard, sediment, and operating limits reduce usable storage.

Use Cases

Sizing a new water tank

Determine the volume of a cylindrical or rectangular tank to ensure it meets your water storage needs for residential, agricultural, or industrial purposes.

Example: Calculate the capacity of a cylindrical tank with a radius of 1.5 m and height of 2 m.

Estimating water supply for a project

Quickly estimate the total water volume available in an existing tank to plan usage, irrigation schedules, or emergency reserves.

Example: Find the volume of a rectangular tank measuring 3 ft by 2 ft by 4 ft.

Frequently Asked Questions

How does the Water Tank Calculator determine volume?
The calculator computes volume based on the tank's shape (cylindrical or rectangular) using the dimensions you provide. For cylindrical tanks, it uses the radius and height; for rectangular tanks, it uses length, width, and height. The result is given in your chosen unit, with conversion options available.
Can I use this calculator for both cylindrical and rectangular tanks?
Yes, the calculator supports both cylindrical and rectangular tank shapes. Simply select the shape that matches your tank, enter the required dimensions, and the calculator will compute the volume accordingly.
What units can I use for the dimensions and volume?
The calculator allows you to input dimensions in various units (e.g., meters, centimeters, feet, inches) and provides volume results in corresponding units (e.g., cubic meters, liters, gallons). You can convert between units as needed.

Tips & Common Mistakes

Tips

  • Always measure the internal dimensions of the tank, not the external, to get the most accurate volume.
  • For cylindrical tanks, ensure you use the radius (half the diameter) for correct calculations.
  • If your tank has a conical or domed bottom, the calculator may not account for that extra volume; consider it separately.
  • Use consistent units for all dimensions to avoid conversion errors; the calculator can convert units for you.

Common Mistakes to Avoid

  • Using the diameter instead of the radius for cylindrical tanks, leading to an overestimated volume.
  • Mixing units (e.g., meters for length and feet for height) without converting, which causes incorrect results.
  • Forgetting to account for the tank's wall thickness when measuring external dimensions, reducing actual capacity.

Last updated: August 13, 2026