Triangle Calculator
Calculate triangle sides, angles, area, and perimeter. Enter at least 3 values including one side.
Sides
Angles
Triangle Properties
Sides
Side a:
Side b:
Side c:
Angles
Angle A:
Angle B:
Angle C:
Triangle Type:
Calculated Results
Basic Measurements
Area:
Perimeter:
Semiperimeter:
Advanced Properties
Inradius:
Circumradius:
Heights (Altitudes)
Height to side a:
Height to side b:
Height to side c:
Medians
Median to side a:
Median to side b:
Median to side c:
Calculation Details
Frequently Asked Questions
You need at least 3 values including at least one side length. Valid combinations include: 3 sides (SSS), 2 sides and included angle (SAS), 2 angles and included side (ASA), 2 angles and any side (AAS), or 2 sides and non-included angle (SSA).
Degrees divide a circle into 360 parts, while radians use the radius length. 180° = π radians. You can enter values like π/2, π/4 when using radians mode.
This occurs when the triangle inequality is violated (sum of any two sides must be greater than the third side) or when angles don't sum to 180°. Check your input values.
When you know two sides and a non-included angle, there might be two possible triangles that satisfy these conditions. The calculator will show both solutions when applicable.
The calculator uses high-precision mathematics and is accurate to several decimal places. However, for professional engineering or construction, verify results with specialized software.
Yes! The calculator can find area using multiple methods: Heron's formula (with 3 sides), SAS formula (with 2 sides and included angle), or base×height when height is calculated from other known values.
Altitude is the perpendicular distance from a vertex to the opposite side. Median connects a vertex to the midpoint of the opposite side. Angle bisector divides an angle into two equal parts.
Interior angles of a triangle must be less than 180° each, and their sum must equal exactly 180°. Angles ≥180° would not form a valid triangle.
Disclaimer
This triangle calculator is provided for educational and reference purposes only. While we strive for accuracy, the results should not be used for professional engineering, construction, or other critical applications without verification. Always consult with qualified professionals for important calculations.