Tire Circumference Calculator

Calculate actual tire circumference from rim size and tire width. Essential for accurate cycling computer calibration and gear calculations.

Results

Visualization

How It Works

Tire circumference = (rim BSD + 2 x tire width) x pi. This is theoretical — actual circumference varies by tire brand, tread pattern, pressure, and rider weight. For cycling computer calibration, the roll-out method is most accurate: mark the ground, ride one wheel revolution, measure. ETRTO is the universal tire sizing standard: width-BSD (e.g., 25-622 = 700x25c). Common values: 700x23c = 2096mm, 700x25c = 2105mm, 700x28c = 2136mm, 27.5x2.2 = 2148mm, 29x2.2 = 2268mm.