Area of a Trapezoid Calculator
The area of a trapezoid is the average of the parallel sides times the height, A = ½(a + b)h: parallel sides of 8 and 5 cm with a 4 cm height give 26 cm².
Perpendicular distance between the parallel sides.
26 cm²
- Area
- 26 cm²
- Median (midsegment)
- 6.5 cm
In other units: 0.0026 m² · 2600 mm² · 2.6 × 10⁻⁹ km² · 2.6 × 10⁻⁷ ha · 0.0279862 ft² · 4.03001 in² · 0.00310957 yd² · 6.42474 × 10⁻⁷ ac · 1.00387 × 10⁻⁹ mi²
Step-by-step solution
- A = ½ × (a + b) × h
- A = ½ × (8 + 5) × 4 = 26 cm²
Area of a Trapezoid Formula
A = ½ (a + b) h
a, b parallel sides, h perpendicular height
Worked Example
A trapezoid with parallel sides 8 cm and 5 cm and height 4 cm:
- A = ½ × (a + b) × h
- A = ½ × (8 + 5) × 4 = 26 cm²
Median (midsegment): 6.5 cm
Same area in other units: 0.0026 m² · 2600 mm² · 2.6 × 10⁻⁹ km² · 2.6 × 10⁻⁷ ha · 0.0279862 ft²
Frequently asked questions
How do I find the area of a trapezoid without the height?
If you know all four sides, find the height first: split off the right triangles at the ends, then h = √(c² − x²) for a leg c and its horizontal projection x. For an isosceles trapezoid, x = (a − b) ÷ 2.
Is a trapezium the same as a trapezoid?
In British and Indian usage, a trapezium has one pair of parallel sides, which is what Americans call a trapezoid. The area formula ½(a + b)h is the same.
What is the median of a trapezoid?
The midsegment joining the midpoints of the legs, with length (a + b) ÷ 2. The area is the median times the height.
Sources
- The International System of Units (SI), 9th edition (SI Brochure), Bureau International des Poids et Mesures .
- Guide for the Use of the International System of Units (SI), NIST Special Publication 811, 2008 Edition, National Institute of Standards and Technology .
Last reviewed: . Factors are stored exactly and computed with 50-digit decimal arithmetic. See how we verify conversion factors.
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APA
Scientific Converters. (2026, October 15). Area of a Trapezoid Calculator. Retrieved October 25, 2026, from https://scientificconverters.com/calculators/area-of-a-trapezoid/
IEEE
Scientific Converters, "Area of a Trapezoid Calculator," scientificconverters.com. Accessed: Oct. 25, 2026. [Online]. Available: https://scientificconverters.com/calculators/area-of-a-trapezoid/