Enter the inside radius and the height of the silo into the calculator to determine the silo capacity.

Silo Capacity Calculator

Enter any 2 values to calculate the missing variable

Silo Capacity Formula

The silo capacity calculator finds the internal volume of a cylindrical silo using the inside radius and the vertical height. This is the correct model for a straight-wall round silo where you want the volume of the cylindrical storage section.

SC = \pi r^2 h
  • SC = silo capacity
  • r = inside radius of the silo
  • h = vertical inside height of the silo

If you know the inside diameter instead of the radius, convert it first:

r = \frac{D}{2}

When the radius and height use the same unit, the answer comes out in cubic units. For example, meters produce cubic meters and feet produce cubic feet.

Rearranged Forms

Because the calculator can solve for a missing value, these equivalent forms are also useful:

h = \frac{SC}{\pi r^2}
r = \sqrt{\frac{SC}{\pi h}}

Input Reference

Input / Output Meaning Typical Units
Inside Radius Distance from the center of the silo to the inside wall m, ft, in
Height Vertical inside height of the cylindrical section m, ft, in
Silo Capacity Total internal cylindrical volume m3, ft3

How to Calculate Silo Capacity

  1. Measure the inside radius of the silo. If you only have diameter, divide it by 2.
  2. Measure the inside height of the cylindrical storage section.
  3. Square the radius.
  4. Multiply by π.
  5. Multiply by the height to get the total internal volume.

Be sure both measurements are in the same unit before calculating. Mixing feet and inches or meters and feet will give the wrong result.

Example Calculation

Suppose a silo has an inside radius of 10 ft and an inside height of 20 ft.

SC = \pi (10)^2 (20)
SC \approx 6283.19 \text{ ft}^3

That means the cylindrical portion of the silo holds about 6,283.19 cubic feet of volume.

What the Result Represents

The result is the geometric internal volume of the silo. In practice, usable storage may be slightly different from theoretical capacity because of real-world features such as:

  • hopper or cone bottoms
  • pitched, domed, or peaked roofs
  • aeration floors or internal structures
  • required freeboard at the top
  • material that does not fill perfectly level

If your silo includes sections other than a simple cylinder, calculate each section separately and combine the volumes as needed.

When This Calculator Is Most Accurate

  • The silo has a round cross-section.
  • The main storage body is cylindrical.
  • You are using inside measurements, not outside dimensions.
  • The measured height matches the portion that actually stores material.

Common Mistakes

  • Using diameter as radius: if you enter diameter directly, the result will be too large.
  • Using outside dimensions: wall thickness reduces actual internal volume.
  • Mixing units: convert all dimensions before calculating.
  • Ignoring non-cylindrical sections: roofs and hoppers change total capacity.

Practical Notes

This calculator gives volume, not material weight. If you need the amount of grain, feed, cement, pellets, or another stored product, you would combine the calculated volume with the material’s bulk density. Because bulk density changes by material type, moisture content, and packing, volume should be treated as the starting point for any inventory estimate.

Frequently Asked Questions

Should I use inside or outside measurements?
Use inside measurements. Capacity depends on the usable internal space.

Can I use this for grain bins and tanks?
Yes, as long as the shape being measured is a cylinder. The same geometry applies to many round storage containers.

What if I only know the diameter?
Convert diameter to radius first, then apply the formula.

Does this include a hopper bottom or roof space?
No. The standard formula here models only the cylindrical body unless those sections are calculated separately.