Perimeter and Circumference

Calculate perimeter for common 2D shapes including square, rectangle, triangle, parallelogram, rhombus, trapezoid, regular polygon, and circle circumference.

Calculate triangle perimeter from three sides, one equilateral side, equal side and base, or two right-triangle legs with triangle inequality checks.

Calculate square perimeter from side, diagonal, area, known perimeter, inradius, or circumradius, with side, diagonal, and area shown for checking.

Calculate rectangle perimeter from length and width, side and diagonal, side and area, or side and known perimeter.

Calculate rhombus perimeter from side length, diagonals, side and height, or side and area, with unit conversion and validation.

Calculate parallelogram perimeter from adjacent sides, diagonals, side with height and area, or side with diagonal and angle.

Calculate trapezoid perimeter from all four sides, isosceles trapezoid inputs, right trapezoid inputs, or bases and height.

Calculate circular sector perimeter from radius and angle, radius and arc length, diameter and angle, or arc length and angle.

Calculate regular polygon perimeter from side length, circumradius, apothem, or area and a whole number of equal sides.

Calculate circle circumference from radius, diameter, or area, and optionally find an arc length from a central angle.