RightSizeTools Practical sizing calculators
Geometry Basics

Triangle Area Calculator

Enter the base and vertical height of a triangle. The height must be measured straight up from the base, not along the angled side.

Last updated: May 2026

Unit system Switch between U.S. customary and metric units. Your choice is remembered on other calculators.

Triangle measurements

The base and height need to be perpendicular. If you only know side lengths, use the right triangle or Pythagorean calculator if applicable.

Visual guide

Which measurement goes where?

Base runs along the bottom. Height is the straight perpendicular distance from the base up to the opposite point.

ft
ft

Buying and sizing notes

How to use this estimate

What this includes

  • The required inputs shown on this page
  • common planning assumptions
  • optional advanced adjustments where provided

What it does not include

  • site-specific professional design
  • local code approval
  • manufacturer-specific requirements
  • installation quality

Common mistakes

  • Leaving a required input at the default when your situation is different
  • ignoring product labels or ratings
  • treating the estimate as an exact final answer

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