Cylinder Volume Calculator Without Radius
Find cylinder radius from volume using the formula r = square root of V divided by pi h. For a cylinder with volume 785.4 cm3 and height 10 cm, dividing 785.4 by 31.42 gives 25, and taking the square root gives 5 cm. Enter your cylinder volume and height below.
Calculator
Missing dimension is derived from other values
Finding circular width from total volume
This tool finds the missing radius when volume and height are known. It is useful in tank design when height and capacity are fixed.
For a complete algebraic breakdown with square root derivations, review our guide on how to find the radius of a cylinder.
Rearranging the formula to isolate radius
To find radius, use r = square root of (V divided by (pi times h)). Divide volume by pi times height, then take the square root.
Frequently Asked Questions
What is the formula to find the radius of a cylinder?
The algebraic formula is r = √(V / (π × h)). This means Radius equals the square root of (Volume divided by (Pi × height)).
Once I find the radius, how do I find the full diameter?
The diameter is simply the entire width of the cylinder's base circle. Once our calculator finds your missing radius, simply multiply that number by exactly 2 to get your diameter.
Does this tool work if I only know the circumference?
If you know the circumference, you don't even need the volume! You can find the radius directly by dividing your circumference by (2 × Pi).
Why would I need to calculate a cylinder without a radius?
It is highly common in architectural design when structural footprint (width) is the only variable you are permitted to change, while height and liquid capacity are legally fixed.
Can I input my volume in gallons or liters?
To use the pure mathematical formula successfully, your volume and height must share the same dimensional unit base (e.g., cubic inches for volume, inches for height). Ensure your inputs match.
How do I find the radius of a cylinder?
Find the radius of a cylinder from the volume and height: (1) Confirm the volume and height use compatible units (e.g., cm³ and cm). (2) Divide the volume by Pi (π) and the height. (3) Take the square root of the result. The formula is: r = √(V / (π × h)). For a cylinder with volume 1,000 cm³ and height 12 cm: r = √(1000 / (π × 12)) = √(26.53) = 5.15 cm.