How to Calculate Area of a Triangle: A Step-by-Step Guide
Calculates the area of a triangle from the measurements you enter. Use any unit, as long as all inputs use the same one.
These calculations come up in school, at work and in daily life, from PSLE and O-Level practice to measuring a room for new flooring. Doing them by hand builds understanding, and a calculator lets you check the answer instantly.
What you need
- Base
- Height
Step by step
- Enter the base.
- Enter the height.
- The results update as you type, or press Calculate.
- Read the area first, then the supporting figures below it.
The formula
½ × base × height
Worked example
For example, with these inputs:
- Base: 10
- Height: 6
the calculator returns:
- Area: 30
A second example
Now change the inputs to:
- Base: 12.5
- Height: 6
the calculator returns:
- Area: 37.5
Practical tips
- When numbers are very large or small, scientific notation makes them easier to compare.
- For exam work, show your method; marks are often given for working, not just the answer.
- Write down the formula before plugging numbers in; it prevents mixing up variables.
- Keep units consistent: convert everything to the same unit before calculating.
Background
Rounding is a common source of small errors. Keep full precision during intermediate steps and round only the final answer to the number of decimal places or significant figures the question asks for.
Calculators are best used to check working rather than replace it, especially for exams where method marks count. Work the problem by hand first, then confirm with the calculator.
Each formula has assumptions built in. Area formulas assume flat shapes, volume formulas assume regular solids and statistical measures assume the data you enter is the data you want to describe. Knowing the assumptions helps you pick the right tool.
Related calculations
- Quadratic Equation Solver: Solves ax² + bx + c = 0.
- Pythagorean Theorem Calculator: Finds the hypotenuse of a right triangle.
- Fraction Simplifier: Reduces a fraction to its lowest terms.
- Ratio Simplifier: Simplifies a ratio.
Want to skip the arithmetic? The free Area of a Triangle Calculator does all of this instantly and updates as you type.
Run your own numbers: Area of a Triangle Calculator