Parallelogram Perimeter Calculator
Find the perimeter of a parallelogram instantly: enter the base length and side length, and the calculator applies P = 2(a + b) to give the total boundary length.
units
units
P = 2 × (a + b)
- 1
Sum of base and side (a + b)
6 + 8 = 14 - 2
Perimeter = 2 × (a + b)
2 × 14 = 28
How does this calculator work?
Parallelogram perimeter = 2 × (base + side): P = 2(a + b). Opposite sides of a parallelogram are equal, so you only need two measurements. If a = b it is a rhombus (P = 4a); if angles are 90° it is a rectangle. No angle information needed for the perimeter.
Formula
How this is calculated
A parallelogram has two pairs of parallel, equal-length sides. The base pair has length b each, and the side pair has length a each. Adding all four sides gives the perimeter: b + a + b + a = 2(a + b). Because opposite sides are congruent by definition, you only need to measure two distinct edge lengths.
Notice that the perimeter depends only on the two side lengths — not on the slant angle or the interior height. Two parallelograms with the same a and b can look very different (one nearly flat, one nearly upright) and yet have identical perimeters. The area, by contrast, does depend on the angle because area = base × perpendicular height.
Special cases: if a = b, the parallelogram is a rhombus and P = 4a. If all angles are right angles, it is a rectangle or square with the same formula. This calculator works for any parallelogram regardless of angles.
Frequently asked questions
No. The perimeter P = 2(a + b) depends only on the two distinct side lengths, not on the slant angle. The angle affects the area and the diagonal lengths, but not the perimeter.
The base (b) is the horizontal bottom edge (and the parallel top edge). The side (a) is the slanted lateral edge that connects top and bottom. Both pairs of opposite sides are equal in length in any parallelogram.
Yes. A rhombus (a = b) has perimeter 4a. A rectangle has P = 2(length + width). Both are special cases of P = 2(a + b). A square with side s has P = 4s.
Also known as
TG we-Calculate Editorial Team. (2026). Parallelogram Perimeter Calculator [Online calculator]. TG we-Calculate. https://we-calculate.com/calculator/parallelogram-perimeter-calculator
TG we-Calculate Editorial Team. "Parallelogram Perimeter Calculator." TG we-Calculate. 2026. https://we-calculate.com/calculator/parallelogram-perimeter-calculator.
TG we-Calculate Editorial Team, "Parallelogram Perimeter Calculator," TG we-Calculate, 2026. [Online]. Available: https://we-calculate.com/calculator/parallelogram-perimeter-calculator
@misc{wecalculate_parallelogram_perimeter_calculator, title = {Parallelogram Perimeter Calculator}, author = {{TG we-Calculate Editorial Team}}, howpublished = {\url{https://we-calculate.com/calculator/parallelogram-perimeter-calculator}}, year = {2026}, note = {TG we-Calculate} }
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