Triangle Calculator
A Triangle Calculator is a handy, precision tool for students, educators, engineers, architects, and hobbyists who need quick, reliable triangle geometry results. Enter known values (sides, angles, height, or coordinates) and the calculator instantly returns complete triangle properties — from basic measures like area and perimeter to advanced values like inradius and circumradius.
What this Triangle Calculator does:
Compute area using multiple methods: base × height ÷ 2, Heron’s formula (from three sides), or trigonometric formulas (½ab·sin C).
Find perimeter by summing side lengths.
Solve triangles from common input sets: SSS, SAS, ASA, AAS, and right-triangle (useful for trigonometry and surveying).
Calculate missing sides and angles using the Law of Sines and Law of Cosines.
Handle right triangles directly with Pythagoras, sine, cosine, and tangent results.
Return altitude, medians, and angle bisectors for deeper geometric analysis.
Compute inradius and circumradius (useful in geometry proofs and engineering).
Work with coordinates: input vertex coordinates (x,y) to get side lengths, area (via the shoelace formula), centroid, and orientation.
Provide exact and numeric results where possible, plus step-by-step working (ideal for learning and verification).
Support multiple units: centimeters, meters, inches, feet — conversions shown automatically.
Show visual aid: optional diagram that labels sides and angles for clarity (great for classroom demonstrations).
Triangle Calculator – India, USA, UK & More
Enter the lengths of three sides to determine the triangle type, perimeter, and area.
Triangle Calculator
Enter known values and choose an input method. The calculator will solve the triangle and show area, perimeter, altitudes, medians, inradius, circumradius, centroid, and step-by-step work.
- This tool works for non-degenerate triangles. If the input can't form a valid triangle you'll see an error.
- Angles are handled in degrees. All computed numeric outputs show reasonable rounding (4 decimal places).
How to use:
Choose the input mode (e.g., SSS, SAS, ASA, coordinates, height+base).
Enter the known values and select units.
Get instant results: area, perimeter, all angles, altitudes, medians, inradius, circumradius, centroid coordinates, and a labeled diagram.
Optionally view step-by-step calculations to learn or verify results.
Whether you’re solving homework problems, double-checking a design, or teaching geometry, our Triangle Calculator makes triangle math fast, accurate, and educational.