Area of a Trapezoid Calculator A = (a+b)·h/2. Base a Base b Height Area 26 Step-by-step with your numbers: 1. Values used: 2. Base a = 8 3. Base b = 5 4. Height = 4 5. Area = 26 Did we solve your problem today? 👍 Yes 👎 No Thanks for the feedback! Average of bases × height. FAQ Right trapezoid? Same formula. Related calculators Trapezoid Area Calculator Find the area of a trapezoid. Parallelogram Area Calculator (Alias) A = b × h. Triangle Area Calculator Find a triangle's area from its base and height.