PrimeCalcPro
Explore 1070+ free calculators — math, finance, health & more.

Inscribed Circle Calculator

Radius of inscribed circle in a triangle

Inscribed Circle (Inradius)

Side a
Side b
Side c

The inscribed circle (incircle) is the largest circle that fits inside a triangle, tangent to all three sides. Its radius (inradius) equals the triangle area divided by the semi-perimeter.

  1. 1r = Area / s
  2. 2Where s = (a+b+c)/2 (semi-perimeter)
  3. 3Area found via Heron's formula
  4. 4Centre is at the intersection of the angle bisectors (incentre)
Triangle 3, 4, 5=r = 6/6 = 1
Triangle 5, 12, 13=r = 30/15 = 2
SidesAreaSemi-perimeterInradius r
3,4,5661
5,12,1330152
8,15,1760203
6,8,1024122
🔒
100% Gratis
Ingen registrering
Præcis
Verificerede formler
Øjeblikkelig
Resultater med det samme
📱
Mobilvenlig
Alle enheder

Settings

Theme

Light

Dark

Layout

Language

PrivacyTermsAbout© 2025 PrimeCalcPro