Trapezoid Area & Perimeter Calculator
Trapezoid Area & Perimeter Calculator
A trapezoid (trapezium) has exactly one pair of parallel sides, called the bases, connected by two non-parallel legs. Enter both bases, the perpendicular height between them, and the two legs, and this calculator finds the area and perimeter, along with a diagram and the full step-by-step working.
- Area = ½(a+b)h, the average of the two bases times the height - for bases 10 and 6 with height 5, that's ½ × 16 × 5 = 40 square units.
- Perimeter = a + b + c + d, simply the sum of all four sides - for bases 10 and 6 with legs 4.5 and 4.5, that's 10 + 6 + 4.5 + 4.5 = 25 units.
- The height must be measured perpendicular to the two bases, not along a leg - unless a leg happens to be perpendicular to the bases (a right trapezoid), the leg length and the height are different.
How do I find the area of a trapezoid?
Average the two bases and multiply by the height: Area = ½(a+b)h. For bases 10 and 6, height 5: ½ × (10+6) × 5 = 40.
What's the difference between a base and a leg?
The bases are the two parallel sides (usually of different lengths); the legs are the two non-parallel sides connecting them - a trapezoid needs all four measurements to find its perimeter.
Trapezoid Area & Perimeter Calculator
A trapezoid (trapezium) has exactly one pair of parallel sides, called the bases, connected by two non-parallel legs. Enter both bases, the perpendicular height between them, and the two legs, and this calculator finds the area and perimeter, along with a diagram and the full step-by-step working.
- Area = ½(a+b)h, the average of the two bases times the height - for bases 10 and 6 with height 5, that's ½ × 16 × 5 = 40 square units.
- Perimeter = a + b + c + d, simply the sum of all four sides - for bases 10 and 6 with legs 4.5 and 4.5, that's 10 + 6 + 4.5 + 4.5 = 25 units.
- The height must be measured perpendicular to the two bases, not along a leg - unless a leg happens to be perpendicular to the bases (a right trapezoid), the leg length and the height are different.
How do I find the area of a trapezoid?
Average the two bases and multiply by the height: Area = ½(a+b)h. For bases 10 and 6, height 5: ½ × (10+6) × 5 = 40.
What's the difference between a base and a leg?
The bases are the two parallel sides (usually of different lengths); the legs are the two non-parallel sides connecting them - a trapezoid needs all four measurements to find its perimeter.