Area counts square units
Area measures a flat region. If lengths are entered in meters, the result is in square meters. A perimeter measures the boundary and has ordinary length units instead.
Convert all dimensions to the same unit before calculating. Squared units change by the square of a conversion factor: one square meter contains 10,000 square centimeters, not 100.
Match the measurement to the shape
A rectangle uses two perpendicular sides. A triangle uses a base and the perpendicular distance to the opposite vertex. A sloping side is not generally the triangle’s height.
A circle formula uses the radius. If you know the diameter, halve it first. Using the diameter as the radius makes the computed area four times too large.
Break complicated regions into simple pieces
For a composite floor plan, split the shape into rectangles or triangles, calculate each area, then add. Subtract holes or cutouts rather than counting them twice.
The tool calculates ideal geometric shapes. Real material estimates may need allowances for seams, waste or an irregular boundary; those allowances are not included automatically.
LET’S WORK IT THROUGH
A triangular panel has base 12 cm and perpendicular height 7 cm. Find its area.
- Use A = base × height ÷ 2.
- 12 × 7 = 84.
- 84 ÷ 2 = 42.
THE ANSWERThe panel area is 42 cm².
YOUR TURN
A small check for understanding.
Find the area of a circle with diameter 10 cm.
Reveal the answer
25π cm², approximately 78.54 cm². Its radius is 5 cm.
Now try your own numbers.
The area calculator includes input guidance and the limits of its supported calculations. Use it alongside the method above.
Open Area calculator ↗A note on precision: preserve exact fractions where possible and round numerical results at the end. Found an unclear step? Prepare a correction report.