Isosceles Trapezoid Area Calculator
This isosceles trapezoid area calculator will help you deal with these very particular trapezoids. Recall that we say that a trapezoid is isosceles if its legs have the same length. You'll experience no trouble using Omni's isosceles trapezoid area calculator, but we know that life is hard and you sometimes have to calculate with pen and paper. Don't worry — we will teach you how to find the area of an isosceles trapezoid with the help of dedicated formulas.
What is the area of an isosceles trapezoid?
There are several dedicated isosceles trapezoid area formulas:

bases
a,b
and heighth
given:A = (a + b) * h / 2

bases
a,b
and legc
given: computeh
via the Pythagorean Theorem (h
is the square root ofc²  (ab)²/4
) andA = (a + b) * h / 2

bases
a,b
and angleα
given: computeh
astan(α) * (ab)² / 4
and thenA = (a + b) * h / 2

base
a
, legc
and angleα
given: computeh
asc * sin(α)
andb
asa  2 * c * cos(α)
, thenA = (a + b) * h / 2
Choose the isosceles trapezoid area formula that suits the data that is available (for notation, see the picture below). Or just use our isosceles trapezoid area calculator!
Useful trapezoid resources
Besides the isosceles trapezoid area calculator, Omni has a vast collection of trapezoidrelated tools. Make sure to take a look at:
 Trapezoid calculator
 Area of a trapezoid calculator
 Trapezoid perimeter calculator
 Trapezoid side calculator
 Trapezoid angle calculator
 Trapezoid height calculator
 Midsegment of a trapezoid
 Isosceles trapezoid calculator
 Right trapezoid calculator
 Right trapezoid area calculator
 Area of an irregular trapezoid calculator
FAQ
How do I compute the area of an isosceles trapezoid given diagonal?
You can compute the area of an isosceles trapezoid as:
A = 0.5 × d² × sin(φ)
where:
A
is the area of the trapezoid;d
is the length of a diagonal; andφ
is the angle between the diagonals.