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What does this converter do?
Dress size converter: convert your bust and waist measurements between US, UK, EU, and Italian dress sizes instantly. Free, private, runs in your browser.
- US to UK is +4 (US 8 = UK 12); US to EU is +30 (US 8 = EU 38).
- Vanity sizing means a modern US 8 matches a 1968 US 14.
- Bust, waist, hip in cm are the only stable reference across brands.
How this calculator works
Formula
US/UK/EU dress sizes step by bust circumference: US 8 = UK 12 = EU 38 ≈ 91.5 cm bust. Letters (XS-XL) compress two numeric sizes each and vary most between brands.
Sources
Sources support the method, terminology, or planning context. Editable assumptions remain your responsibility.
Assumptions to verify
- Manufacturer charts vary; conversion outputs are the standard-mapping midpoint.
- Measurements are body measurements unless the tool labels them as garment measurements.
- Between-size results round per the rule stated in the FAQ.
Frequently asked questions
Why is my size different at every store?
Letter and number labels are brand conventions mapped onto real body measurements. Charts that print actual cm ranges are the only comparable layer, which is what this converter uses.
What if I fall between sizes?
Round the direction that matches use: clothing and shoes generally round up.
Cite this tool
BoringToolsKit. “Dress Size Converter.” boringtoolskit.com/dress-size-converter/ (reviewed 2026-09-20). Free to reference in articles, syllabi, and answer posts with a link.
Privacy: Inputs and results stay in this browser. Conversion runs locally in your browser; review the output before relying on it.
Worked example: US 8 on the tape
The conversion is two fixed offsets, so it works the same for every input. Take US 8, the middle of most brand size charts. EU = 8 + 32 = 40. UK = 8 - 2 = 6. So a US 8 shopper in Paris asks for a 40, and in London asks for a 6. Check it the other way: a UK 12 is US 14 (12 + 2), which is EU 46 (14 + 32). The offsets point in opposite directions because EU numbering runs about 32 sizes higher than US while UK runs 2 lower.
A second example shows why the displayed text handles the low end specially. Enter US 0: EU = 0 + 32 = 32, but UK = 0 - 2 = -2, and there is no negative UK dress size. The result panel prints UK '0 (US 0/2)' instead, reflecting that UK charts usually start at 4 and that a US 0/2 customer wears roughly a UK 4. The arithmetic stays exact; only the UK display is clamped.
Sanity-check against the extremes: US 24 maps to EU 56 and UK 22, both of which appear on extended size charts. US 12 maps to EU 44 and UK 10. Every value in the accepted 0 to 24 range produces a valid pair under the same two offsets, so the formula itself never bends. The offsets are the whole mechanism.
Where the offsets break down
The formula accepts US 0 through 24 only. Type -2 or 30 and it rejects the entry and asks for 0 to 24, so there is no invented output at the boundaries; the cap is a data statement, not a soft suggestion. Within the range, a US 0 produces the odd UK situation above, and a US 2 maps to UK 0, which real UK charts rarely print. That is honest: the offsets cannot produce a chart-perfect UK label at the very bottom of the scale.
The bigger limit is that dress sizes are not a single number system with clean offsets. Brands drift by 1 to 2 sizes in both directions; a 'US 8' at one fast-fashion label can measure like a US 6 or a US 10 elsewhere. EU 40 on one brand can fit like a 38 or 42 on another. The offsets give the right starting point for a fitting room, not a guarantee about any specific garment.
Practical use: treat the EU number as the label to look for first, then adjust by fit history. If you already know an EU 40 runs small for you, ask for the 42 rather than re-deriving anything here. Sizing charts on the product page and a waist or bust measurement in centimetres settle what the converted number cannot. The converter tells you which rack to walk to; the tape and the mirror decide.