Triangle Calculator

Solve Any Triangle – Area, Sides, Angles, Perimeter

Our free Triangle Calculator lets you solve any triangle for area, sides, angles, and perimeter. Enter any valid combination of sides (a, b, c) and angles (A, B, C) and the calculator will find the rest using the Law of Sines, Law of Cosines, and Heron's formula. Modern, mobile-friendly, and floating design for the best experience on any device.

Parameters & Features

  • a, b, c: Side lengths of the triangle (any units)
  • A, B, C: Angles of the triangle in degrees
  • Area: Calculated using Heron's formula or trigonometry
  • Perimeter: Sum of all sides
  • Solves: SSS, SAS, ASA, AAS, SSA cases
  • Floating Card: On desktop, the calculator floats as you scroll, always accessible
  • Mobile UX: Calculator appears at the top, followed by detailed explanations and FAQs

FAQs

  • What is a triangle calculator?
    A tool that solves for unknown sides, angles, area, and perimeter of a triangle given any valid combination of sides and angles.
  • Which triangle cases are supported?
    SSS (three sides), SAS (two sides and included angle), ASA/AAS (two angles and a side), SSA (ambiguous case).
  • What formulas are used?
    Law of Sines, Law of Cosines, Heron's formula, and basic trigonometry.
  • What units should I use?
    You can use any consistent units for sides (e.g., cm, m, in). Angles must be in degrees.
  • Can I solve for area and perimeter?
    Yes, both are calculated automatically.
  • What if I enter invalid values?
    The calculator will show an error if the values do not form a valid triangle.
  • Is this calculator mobile-friendly?
    Absolutely! The layout adapts for mobile and desktop, with floating card on desktop and top placement on mobile.

Understanding Triangle Calculations

  • This calculator helps you solve for unknown sides and angles in a triangle using trigonometric and geometric principles.
  • By entering known values, you can see how the laws of sines and cosines, as well as area and perimeter formulas, are applied in practice.
  • Understanding triangle calculations is essential in geometry, trigonometry, engineering, and many real-world applications.

How to Use the Triangle Calculator

  • Enter any valid combination of sides (a, b, c) and angles (A, B, C).
  • Leave unknowns blank. At least three values, including one side, are required.
  • Click Calculate to solve. The calculator will find all missing sides, angles, area, and perimeter.
  • Review the results and formulas below the calculator.

Triangle Calculator