Calculating the capacity of a circular water tank is essential for various domestic and industrial applications. This guide provides a clear, step-by-step method using standard formulas and unit conversions.

What You Need to Know Before Starting

To calculate the water capacity, you need:

• Diameter of the tank
• Height of the tank
• A basic understanding of the volume formula for a cylinder

Let’s assume a circular tank with the following dimensions:

• Diameter (D): 5 meters
• Height (H): 3 meters

Step 1: Use the Volume Formula for a Cylinder

The formula to calculate the volume of a cylindrical tank is:

Volume = π × (D² / 4) × H

Now plug in the values:

= 3.142 × (5² / 4) × 3
= 3.142 × (25 / 4) × 3
= 3.142 × 6.25 × 3
= 58.91 cubic meters (CUM)

This is the tank’s total volume.

Step 2: Convert Cubic Meters to Liters

We know:

1 cubic meter = 1,000 liters

So, to convert:

= 58.91 × 1,000
= 58,910 liters

Your circular tank holds 58,910 liters of water.

Step 3: Convert Liters to Gallons

If you need the volume in US gallons:

1 US gallon = 3.7854 liters

Now convert:

= 58,910 ÷ 3.7854
= 15,563 gallons

So, the water tank can store approximately 15,563 gallons.

Quick Summary

Important Notes

• Always measure internal dimensions for accurate volume.
• Use π as 3.142 for better precision.
• Confirm unit standards based on region (UK and US gallons differ).

Why This Matters

Accurate water storage calculations help in designing efficient systems. Whether for rainwater harvesting, irrigation, or municipal use, understanding your tank’s capacity is vital.

Click Here To See Design of Circular Water Tank Excel Sheet