How deep should an armhole be?

Standard armhole depth is 18-25cm for adults, depending on garment size and style. Measure from the underarm to the top of the shoulder. Closer-fitting garments have shallower armholes; drop-shoulder styles have deeper ones.

How many stitches do I bind off for the armhole?

The initial underarm bind-off is small — about 1.5-3.5cm of stitches (often only 4-8 sts), cast off across the first one or two rows. This is far less than the total armhole reduction. The remaining shaping is worked as gradual single-stitch decreases on right-side rows, not bound off, which gives a smooth curved armscye.

What is the difference between shaped and drop-shoulder armholes?

Shaped armholes curve inward with bind-offs and decreases, giving a fitted look. Drop-shoulder armholes are straight with no shaping - the sleeve hangs below the actual shoulder. Modified drop shoulders have minimal shaping.

How do I make armholes match on front and back?

Work the same bind-off and decrease sequence on both front and back pieces. Mark the beginning of armhole shaping with stitch markers and count rows carefully. For knitting in the round, place markers at both underarm points.

Should I adjust armhole depth for different sleeve types?

Yes. Set-in sleeves need a standard-depth armhole. Cap sleeves need a shallower armhole. Dolman or batwing sleeves need a very deep armhole extending nearly to the waist.

KnitCalcs

Armhole Calculator — Depth & Bind-Off Shaping

Calculate armhole depth, initial bind-off, and shaping decreases for fitted garments.

Chest Circumference

Finished garment chest measurement

Armhole Depth

Underarm to shoulder top

Stitch Gauge (per 10cm)

Stitches per 10cm from your gauge swatch

Row Gauge (per 10cm)

Rows per 10cm from your gauge swatch

How We Calculate This

This calculator estimates set-in armhole shaping from your chest circumference, desired depth and gauge. The per-side reduction is the difference between the body width and the cross-back (shoulder) width, halved.

The formula

Per-side reduction ≈ 4–5% of chest circumference (the body-to-cross-back difference, divided by two)

Initial underarm bind-off ≈ 30–40% of that reduction

Remaining stitches worked as gradual decreases every RS row

Frequently Asked Questions

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Last updated: February 2026

All calculations are estimates based on standard yarn weights and gauge. Results may vary with individual tension, yarn brand, and needle size.