Suit Size Calculator

What size suit am I? Enter your height, weight, and build to instantly estimate your US jacket size, shirt size, and trouser waist.

Quick answer

US suit sizes combine your chest measurement in inches with a length letter: S (short) for heights under 5'8", R (regular) for 5'8"–6'1", L (long) for 6'1"–6'4", and XL for 6'4"+. A 5'10", 170 lb man with regular build typically wears a 40R jacket, 34" trousers, and 15.5" neck shirt. Enter your details below for an instant estimate.

Free · No sign-up · Based on standard US menswear sizing conventions · Trusted by 434+ Nathan Tailors clients

Your details

Height

Weight

Age

Build

Your estimated size

40R

or 42R for a looser cut

Chest

40"

102 cm

Waist

34"

86 cm

Neck / Sleeve

15" / 32"

38 cm / 81 cm

Jacket length

Regular

Style tips for regular build

— Classic fit flatters most balanced proportions.
— Notch lapels and single-breasted work well.
— Medium-weight fabrics (260–320g wool) hang best.

Estimate only. Off-the-rack sizes still require tailoring for most bodies. For a suit that fits perfectly everywhere, we recommend custom.

Book a fitting How to measure yourself

How suit sizing works

US suit sizes are written as a number + letter (40R, 42L, 38S). The number is your chest measurement in inches. The letter is the jacket length:

S (Short) — heights under 5'8" (173 cm)
R (Regular) — heights 5'8" to 6'1" (173–185 cm)
L (Long) — heights 6'1" to 6'4" (185–193 cm)
XL (Extra Long) — heights over 6'4" (193+ cm)

Trouser waist is typically 6 inches smaller than chest for average builds (the “drop”), but can range from 4 inches (larger build) to 8 inches (athletic build). Our calculator adjusts for this automatically.

Common sizes by height and weight

Height	Weight	Regular build	Athletic build
5'8"	150 lb	38R	36R
5'10"	170 lb	40R	38R
6'0"	185 lb	42R	40R
6'0"	200 lb	44R	42R
6'2"	200 lb	44L	42L
6'3"	230 lb	46L	44L

When a calculator isn't enough

Height and weight get you within one size for most bodies. But suits fail on fit, not on size number. What the calculator can't see:

Shoulder width — wider or narrower than average
Posture — forward, upright, or swayback
Chest-to-waist drop — athletic V-shape vs. straight
Arm length relative to torso
Thigh circumference for trouser break

For off-the-rack, use the calculator and expect tailoring. For a perfect fit, skip the compromise and go custom — book a fitting or see all 8 measurement guides.

US to European suit size conversion

US	EU	UK	Chest (inches)
36R	46R	36R	36"
38R	48R	38R	38"
40R	50R	40R	40"
42R	52R	42R	42"
44R	54R	44R	44"
46R	56R	46R	46"

Frequently asked questions

How accurate is a suit size calculator?

A good one gets 80% of people within one size. It's a starting point, not a replacement for measurement.

What does 40R mean?

40-inch chest, regular length jacket (heights 5'8"–6'1").

What size suit for a 5'10", 170 lb man?

Regular build typically 40R jacket, 34" trouser, 15.5" neck shirt. Athletic build usually 38R-40R.

What size suit for a 6'0", 200 lb man?

Regular build typically 44R with 38" trouser. Athletic V-shape is notoriously hard off-the-rack — the chest fits but the waist gapes.

Does this work for women's suits?

This calculator is tuned for US men's tailoring conventions. Women's sizing uses a different system — contact us directly for women's custom suits and bridal separates.

Can I order a custom suit with just these numbers?

No — we need 12+ measurements for a custom build. The calculator narrows down your size; our measurement kit handles the rest.

Why does my size feel different between brands?

Different brands use different fits (slim, modern, classic) at the same nominal size. A 40R can vary by 1-2 inches across brands. Custom eliminates the problem.