Conversion Formulas

Quick math to derive a size from a body measurement — and the rule-of-thumb offsets that approximate them.

How to Measure Sizing Systems Explained Conversion Formulas Quick Lookup — Master Tables Sources

Women (Dresses & Suits)Men (Suits)Shoes Offsets Cheat-Sheet

Women (Dresses & Suits)

Sizes are derived from bust circumference b.

Rule of thumb (women)

UK = US + 4 · EU = US + 30 · EU = UK + 4 · IT = EU + 4 · FR ≈ EU

Women's formulas by region

Region	Formula (b = bust cm, or per note)
US	s = b − 28 (b in inches)
UK	s = b − 24 (b in inches)
IT	s = b/2 (cm)
FR	s = (b − 8)/2 (cm)
DE	s = (b − 12)/2 (cm)

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Men (Suits)

Rule of thumb (men)

jacket EU = UK/US chest(in) + 10 · trouser EU = waist(in) + 16 · collar cm = collar in × 2.54

Men's suit formulas by region

Region	Formula (b = chest cm)
FR	s = (b + 1)/2
DE	s = (b − 1)/2

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Shoes

Shoe conversions

Conversion	Formula
US men vs UK	US = UK + 0.5
US women vs UK	US = UK + 2
UK vs EU	UK ≈ EU − 33
EU from foot	EU ≈ (foot cm + 1.2) ÷ 0.667 (includes ~13–17 mm wiggle)
JP/Mondopoint	= foot length in mm

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Offsets Cheat-Sheet

Always confirm with cm/in

Every offset above is a close approximation and drifts at the extremes and with vanity sizing. Where fit matters, read across the cm/in column, not just the offset.

Rule-of-thumb offsets by category

Category	Rule
Women	UK = US + 4 · EU = US + 30 · IT = EU + 4 · FR ≈ EU
Men jacket	EU = UK/US chest(in) + 10
Men trouser	EU = waist(in) + 16
Dress shirt	collar cm = in × 2.54
Shoes	USm = UK+0.5 · USw = UK+2 · UK ≈ EU−33 · Mondo = foot mm
Kids	EU = height cm · UK/US/AU = age
Bra band	EU = US/UK + 32 (approx)
Units	1 in = 2.54 cm · 1 cm = 0.394 in

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