Circle chord length
Find a chord’s length from its distance to the centre.
Inputs
Use the units shown—
Enter your values and select Calculate.
Formula & explanation
L = 2√(r² − d²)
Variables & units
- Radius
- cm · minimum 0, maximum 1000000000
- Perpendicular distance from centre
- cm · minimum 0, maximum 1000000000
Worked example
Radius 3 cm and distance 1 cm give a chord approximately 5.656854 cm long.
Assumptions
The distance is perpendicular to the chord, measured from the circle’s centre. Equality gives a zero-length limiting chord.
Formula version 1.0.0. JavaScript floating-point arithmetic applies. Results display up to 6 decimal places; stored values retain available precision. Use the units shown.
Practice with an example
Use the default input values to find the answer. The reset icon restores those values.
Calculated on your device. Your latest 100 calculations stay in this browser.