Shoe Size Calculator
Convert your foot length or shoe size across US, UK, EU and cm sizing systems for men and women, free in your browser.
Your foot measurements
Measure heel to longest toe. If your feet differ, use the larger foot.
Widest part of the forefoot — used for narrow/standard/wide guidance only.
Your estimated shoe size
Enter your foot length and press Estimate shoe size. Foot length gives the most reliable starting point; width and brand vary.
Before you rely on this: Use this as a quick guide and check the result against your own working before you rely on it.
How to use this calculator
- Choose adult or kids, then (for adults) men's or women's labelling.
- Measure heel to longest toe and enter your foot length — use the larger foot if they differ.
- Optionally add foot width for narrow/standard/wide guidance, pick the system to show, and press Estimate shoe size.
How it works
The Shoe Size Calculator estimates your shoe size from foot length and converts it across US, UK, EU, AU, JP/CM and Mondopoint, with optional width guidance.
Foot length in millimetres is the most reliable basis for sizing — it is the Mondopoint system. We map your length to the nearest size in each system and use foot width only as a narrow/standard/wide hint, because last shape and brand fit vary too much to predict exactly.
Worked example
280 mm foot length. A 280 mm foot is Mondopoint 280, about EU 44, UK 10 and US Men 11 (US Women ~12.5). Width changes whether a standard or wide fitting feels best.
Tips
- Measure later in the day when feet are at their largest.
- If you are between sizes, try half a size each way and consider the width.
Frequently asked questions
How do I measure my foot length?
Stand on a sheet of paper with your heel against a wall, mark the tip of your longest toe, and measure from the wall to the mark. Measure both feet and use the larger one, ideally at the end of the day.
Why do shoe sizes differ between brands?
Each brand uses its own last (the foot-shaped mould), so the same labelled size can fit differently. Foot length gives a reliable starting point but always check brand-specific guidance.
How accurate are these size results?
They are a helpful starting point, not a guarantee. Brand sizing, garment cut, fabric stretch, body shape and measurement technique all change the best fit, so we show a recommended size plus adjacent sizes rather than one exact answer.
What is Mondopoint?
Mondopoint is an international sizing system based on foot length in millimetres, which makes it a stable anchor for converting between US, UK, EU and other systems.
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Cite this tool
Zerdly. (2026). Shoe Size Calculator. Retrieved from https://www.zerdly.com/tools/shoe-size-calculator/
Tip: Enter any known values to calculate the remaining results.
All calculations run in your browser. Your inputs are never saved or transmitted.