Kettle Volume & Dimensions Calculator
Volume of a cylindrical kettle from its diameter and height, the fill height for a target volume, and litres per cm for marking a sight glass.
Diameter is remembered for your other equipment tools. Assumes a straight-sided cylinder; a flared or rounded kettle will differ slightly near the base.
How it works
A straight-sided kettle is a cylinder, so its volume is the circular area of the base times the height. Working in centimetres gives cubic centimetres, which we divide by 1000 to get litres.
volume (L) = π × (diameter ÷ 2)² × height ÷ 1000
litres per cm = π × (diameter ÷ 2)² ÷ 1000
fill height (cm) = target volume × 1000 ÷ (π × (diameter ÷ 2)²)
Sources: exact geometry of a right circular cylinder - no model, just the dimensions you measure.
Frequently asked questions
- How do I measure my kettle for this?
- Measure the inside diameter across the top (ignore the wall thickness) and the inside height from the bottom up. A straight-sided kettle is a cylinder, so those two numbers give its volume. If your pot flares or has a rounded bottom, treat the result as a close approximation.
- What is "litres per cm" for?
- It is how much volume one centimetre of height represents in your kettle. Multiply it out to make your own volume marks on a dip stick or sight glass - for example, if your kettle holds 1.1 L per cm, then 5 cm of wort is about 5.5 L. It is the fastest way to volume-mark a kettle without filling it jug by jug.
- Why does the fill height matter?
- Knowing the height a target volume reaches lets you check a batch fits with boil-over headroom, and lets you hit a pre-boil volume by sight instead of guessing. Pair it with the kettle size calculator to confirm your pre-boil volume clears the rim.