Best Fit Calculator for Online Shoppers
This is a fit calculator, not a size chart. The difference: a size chart says 'a size 8 is 36-inch bust'. This calculator factors fit mode (slim, regular, relaxed), brand calibration, and your actual measurements to predict whether the garment fits — not just what the label number is. Use the calculator below to get your exact fit in 30 seconds.
How it works
Measure yourself
Take your bust, waist, and hips with a soft tape. See the full measurement guide.
Enter the numbers
Type your measurements into the calculator above. Pick inches or cm — the tool converts both ways.
Get your size
Match the result against the brand's chart and order with confidence.
Women's tops & dresses — bust-driven sizing
| Size | US | UK | EU | Bust |
|---|---|---|---|---|
| XS | 0–2 | 4–6 | 32–34 | 31–33" |
| S | 4–6 | 8–10 | 36–38 | 33–35" |
| M | 8–10 | 12–14 | 40–42 | 35–37" |
| L | 12–14 | 16–18 | 44–46 | 38–40" |
| XL | 16–18 | 20–22 | 48–50 | 41–43" |
| XXL | 20–22 | 24–26 | 52–54 | 44–46" |
Frequently Asked Questions
How is this different from a regular size chart?
A size chart maps a body measurement to a size number. A fit calculator predicts whether the garment will fit, factoring brand calibration, fit mode (slim/regular/relaxed), and stretch fabric.
Does the calculator remember my measurements?
It runs in your browser session — no data stored on a server. For persistent measurements, use the calculator embedded in your favorite brand's product page (powered by Tailor Size Guide).
Can the calculator predict fit across categories?
Yes. Bust, waist, and hip drive most categories. Add inseam for bottoms, shoulder for tailored tops, neck for dress shirts.
Is the calculator free?
Yes — no signup, no payment, no email. The free version is what you're using now. Brands embed a customized version on product pages via the Tailor Size Guide app.
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Run a fashion store on Shopify?
Add this calculator to your product pages. Per-product size charts, instant fit recommendations, and 30%+ reduction in sizing-driven returns.