Dart intake is the total width of fabric taken in by the dart at its widest point (the seam line). For a bust dart, this is typically 2–4cm. The intake is divided equally on each side of the dart centreline.

How long should a dart be?

Bust darts typically end 2.5cm before the bust point. Waist darts on a bodice are 8–12cm long; on a skirt, 10–15cm. The dart should point toward the fullest body point but stop short of it.

How do I sew a smooth dart?

Sew from the widest point to the tip, tapering to nothing. Do not backstitch at the tip — instead, tie off the threads. Press bust darts downward and waist darts toward centre front/back.

SewCalcs

Dart Calculator — Dart Dimensions & Shaping

Calculate dart width, length and angle for bodice, skirt and trouser darts.

Dart Intake

Total width at widest point

Dart Length

Dart Type

How We Calculate This

Dart dimensions are calculated from the intake (width) and desired length.

The formula

Half-width = Dart intake ÷ 2

Dart angle = 2 × arctan(Half-width ÷ Length)

Frequently Asked Questions

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Last updated: February 2026

All calculations are estimates. Always verify quantities before cutting or purchasing fabric.