How do I measure for weft extensions?

Measure the head circumference from ear to ear across the back of the head. A full head sew-in typically needs 3 rows of wefts at different lengths — the bottom row is widest (about 80% of circumference), middle row about 60%, and top row about 40%. The total weft length is the sum of all rows.

What is the difference between machine and hand-tied wefts?

Machine wefts have a thicker, more durable base made by machine sewing. Hand-tied wefts have a thinner, flatter base created by hand-tying individual strands. Hand-tied wefts lie flatter against the head and are less detectable, but they are more delicate and expensive. Both are sewn onto braided cornrow tracks.

How many rows of wefts do I need?

A full head sew-in typically uses 3 rows of wefts. A three-quarter head uses 2 rows. Half head or volume only uses 1 row. Rows are placed horizontally from ear to ear, leaving a gap at the hairline and parting area so natural hair covers the attachment points.

How much do sew-in weft extensions weigh?

A full head of sew-in extensions weighs approximately 100-200g depending on the length and density of the hair. Longer extensions (55cm+) weigh more per centimetre of weft. The weight should be distributed across multiple rows to prevent tension on any single braid track.

CutCalcs

Weft Length Calculator — Sew-In & Clip-In Measurements

Determine weft lengths and quantities needed for sew-in or clip-in extensions.

Head Circumference

Measure ear to ear across back

Coverage

Weft Type

Extension Length

Cost Per cm of Weft

Optional

How We Calculate This

This calculator determines the total weft length needed based on head circumference, desired coverage and weft type, then estimates the number of individual weft pieces required.

The formula

Total weft length = Sum of row lengths based on head circumference

Weft count = Total length / Individual weft width

Bottom row: 80% of effective circumference
Middle row: 60% of effective circumference
Top row: 40% of effective circumference

Frequently Asked Questions

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Last updated: February 2026

All calculations are estimates. Always perform a strand test before chemical services.