Men's Suit Size Conversion: UK, US, EU

For men's suit size conversion, UK and US jacket sizes are the same number, and EU sizes are 10 higher. A UK or US 40 jacket is an EU 50, according to the Primark men's suits, jackets and blazers chart (checked November 2026).

The number alone does not guarantee a fit, because brands cut differently. Stores that want fewer wrong-size orders can use AI size recommendation for fashion stores to match a shopper's body to their own chart.

What is the suit size chart for UK, US and EU?

The table below is an example chart from Primark's men's suits, jackets and blazers page. Primark says actual measurements vary slightly by style and the chart is for reference only, so check your brand's own chart.

UK / US	EU / IT
34	44
36	46
38	48
40	50
42	52
44	54
46	56
48	58

How do you convert a suit size quickly?

Use one rule each way:

• UK or US to EU: add 10. A 42 becomes EU 52.
• EU to UK or US: subtract 10. An EU 50 becomes a 40.

This holds for the chart above. It may not hold for other brands, especially those with their own fit grids.

What does EU 50 mean in UK suit sizes?

EU 50 is a UK and US 40 on this chart. If you were fitted in a UK 40 jacket, look for EU 50 on a European site.

Why does the same size fit differently?

Three things change the fit even when the number matches:

• Cut. Slim, regular and relaxed cuts allow different amounts of room.
• Length. Many brands add a length code, such as short, regular or long. Check whether your brand does.
• Fabric. Structured wool holds its shape, while stretch fabric forgives a small mismatch.

Because charts vary, the safest step is to compare your own chest and waist with the brand's measurements. If you are also converting shirts or trousers, see US to EU men's size conversion.

How do you check a suit jacket size before buying?

1. Measure your chest at the fullest point, over a thin shirt, arms relaxed.
2. Find the brand's size chart and look for the chest range that includes your number.
3. Check the fit note: slim, regular or relaxed.
4. If you are between sizes, choose the larger for a tailored cut that you may want to adjust.
5. Keep the return policy in view, since a wrong fit usually means a return.

For where fit returns come from, read fit-related returns and how to cut them.

What if you are between two suit sizes?

Many men fall between sizes, with shoulders in one size and a waist in another. Use the jacket as your main guide, since shoulders are hard to alter.

A tailor can often take in a jacket that is slightly large. Letting out a jacket that is too small is harder, because there is limited seam allowance. If you can use a tailor, choose the size that fits the shoulders and ask for adjustments.

How do trousers and jackets differ in a suit?

A suit is two pieces, and each has its own size. Jacket sizes use the chest number. Trousers use a waist measurement, and the labels may differ from the jacket.

When a suit is sold as a set, the trousers often come in a matching size. Some brands sell them separately so you can mix sizes. Check whether the store allows this before you order.

What are common mistakes when converting suit sizes?

• Converting shirt sizes with the suit rule. The 10-point rule is for jackets.
• Ignoring length. A 40 jacket can come in short, regular or long.
• Measuring over a heavy layer. Measure over a thin shirt.
• Trusting one chart for every brand. Check the brand's own table.
• Forgetting the fit name. Slim cuts feel smaller than classic cuts at the same number.

A quick worked example

A shopper in Germany has an EU 52 jacket and wants to buy from a UK store. Subtract 10 and look for a UK 42. Then check the store's chest range for a 42 against the shopper's own chest measurement. If it fits inside the range, order. If not, go by the measurement.

What should stores show on a suit page?

Show your own measurements, not only a converted label. A table with chest in centimeters and inches, plus the UK/US and EU labels, removes most guessing.

With ZeDaq.ai, a merchant enters their own size chart for tops and outerwear, and a 30-second body scan from one photo plus height recommends a label from it. Sizing is covered by the free plan's 3 measurements a month for testing.

Children's sizes follow different rules, so see kids clothing size conversion separately.

FAQs

Is a UK 40 the same as a US 40 suit?

Yes. UK and US jacket numbers match on the Primark chart above. Cut can still differ by brand.

What is a 50 EU suit size in the US?

It is a US 40 on this chart. Add or subtract 10 to move between the two systems.

Does the 10-point rule work for shirts?

Not reliably. Shirt sizes often use collar measurements or letters, so use the brand's own chart.

Should I size up in a suit jacket?

Not automatically. Compare your chest measurement with the chart, then use fit notes on cut and fabric.