Cylinder Diameter
Calculate the diameter of a cylinder from its radius using D = 2r. Get instant results with formula breakdown for any geometry or engineering problem.
About This Calculator
The Cylinder Diameter Calculator computes the diameter of a right circular cylinder from its radius using the formula D = 2r. Since the base of a cylinder is a circle, the diameter is simply twice the radius - the same relationship used for any circle.
This tool is useful for students learning circle geometry, engineers sizing cylindrical components, machinists working with pipes and tubes, and anyone who needs to quickly find the diameter of a cylinder from its known radius.
For related calculations, try our Cylinder Circumference Calculator for finding circumference from radius, or the Cylinder Volume Calculator for volume from radius and height.
Frequently Asked Questions
What is the formula for cylinder diameter?
The diameter of a cylinder is simply twice its radius: D = 2r. This is the same relationship as for any circle since the base of a right circular cylinder is a circle.
How is the diameter different from the radius?
The radius is the distance from the center of the circular base to its edge. The diameter is the distance across the circle passing through the center, equal to twice the radius. If the radius is 5 cm, the diameter is 10 cm.
What units should I use for the radius?
You can use any consistent unit (meters, centimeters, inches, feet). The diameter will be in the same unit as the radius. For example, if you enter radius in meters, the diameter will be in meters.
Can I calculate the diameter from the circumference?
Yes, you can also find the diameter from the circumference using the formula D = C / pi, where C is the circumference. Conversely, use our Cylinder Circumference calculator to compute circumference from radius.
How do I find the diameter if I know the cylinder volume?
If you know the volume and height, first find the radius using r = sqrt(V / (pih)), then double it to get the diameter. Or use our Radius Of Cylinder calculator to find the radius first.
Is this cylinder diameter calculator free?
Yes, all calculators on Calculy are completely free to use with no limits or registration required.