Z-plasty Calculator
Length gain by limb angle, with an interactive diagram.
Central limb along the vertical scar, lateral limbs at 60° to it. Dashed: the new central limb after transposition; right: the transposed Z with its central limb now horizontal, lengthening the scar axis by 75%.
Theoretical length gain
75%
Resulting length along the axis
35.0 mm
20 mm + 15.0 mm gain
Theoretical gains (30°→25%, 45°→50%, 60°→75%, 75°→100%, 90°→120%). Actual gain is usually less due to skin elasticity; wider angles raise closure tension. Education only.
Z-plasty length gain
A Z-plasty transposes two triangular flaps to lengthen and reorient a scar or contracture. The theoretical longitudinal length gain depends on the angle of the lateral limbs to the central limb.
Length gain by limb angle
Classic theoretical gains are 25% at 30°, 50% at 45°, 75% at 60°, 100% at 75° and 120% at 90°. Sixty degrees is the common compromise — wider angles give more length but raise closure tension.
When Z-plasty is used
Z-plasty releases linear scar contractures, breaks up straight scars across the relaxed skin tension lines, and realigns or lengthens tissue in reconstructive and aesthetic surgery.
Actual length gain is usually less than the theoretical value because of skin elasticity. Education only — plan to the patient's tissue and tension.