Any triangle’s area is half that of the parallelogram it forms with a copy of itself.
How to use the Triangle Area Calculator
- Base
- Height
- Want to work backwards? Type a value into Area and Height is calculated for you.
Results update as you type, and every field accepts the units shown in its menu.
How it works
Multiply base by perpendicular height and halve it. With two sides and the included angle, use the sine formula.
Inputs explained
| Field | What to enter |
|---|---|
| Base | Units: m, cm, mm, km, in, ft … |
| Height | Units: m, cm, mm, km, in, ft … |
Example values
How the main result changes when Height changes and everything else stays at the example values above:
| Height (m) | Area (m²) |
|---|---|
| 3 | 15 |
| 4.5 | 22.5 |
| 6 | 30 |
| 7.5 | 37.5 |
| 9 | 45 |
| 12 | 60 |
Formula
Area = ½ × base × heightArea = ½ × a × b × sin(C)Worked example
Inputs — Base: 10 m; Height: 6 m.
Results — Area = 30 m².
Frequently asked questions
What is the height of a triangle?
The perpendicular distance from the base to the opposite vertex.
What if I only know three sides?
Use Heron’s formula.
What formula does the Triangle Area Calculator use?
Area = ½ × base × height.
Can I work backwards from the result?
Yes. Type the result you want into Area and the calculator finds the matching height.