Boot Sizes: Shaft Height, Calf Circumference and How Boots Should Fit
Boots use the same length sizes as shoes, but the shaft adds two measurements that shoes do not have: how tall it is and how wide it is at the calf. Here are the standard figures for each boot style and how to size boots that are worn with thick socks or safety toes.
Boot shaft heights, measured from the arch to the top edge, are typically 3-6 in (8-15 cm) for ankle boots, 8-12 in (20-30 cm) for mid-calf boots, 14-18 in (36-46 cm) for knee-high boots and 20 in (51 cm) or more for over-the-knee boots. Boot length sizes follow the same UK, EU and US scales as shoes.
- Ankle boot shaft
- 3-6 in (8-15 cm)
- Mid-calf shaft
- 8-12 in (20-30 cm)
- Knee-high shaft
- 14-18 in (36-46 cm)
- Standard calf width
- 14-15 in (36-38 cm)
On this page
Boot shaft heights by style
Retailers list shaft height from the arch (where the sole of the foot starts to rise at the heel) to the top of the boot opening. Heel height is not included, so a 15 in shaft on a 3 in heel stands about 18 in tall on the floor.
| Style | Shaft height (in) | Shaft height (cm) | Where it ends on an adult |
|---|---|---|---|
| Ankle boot / bootie | 3-6 | 8-15 | At or just above the ankle bone |
| Chelsea and chukka | 4-6 | 10-15 | Just above the ankle |
| Work boot "6-inch" | about 6 | about 15 | Lower shin |
| Work and military "8-inch" | about 8 | about 20 | Above the ankle, below the calf |
| Mid-calf | 8-12 | 20-30 | Below the widest part of the calf |
| Western / cowboy | 10-13 | 25-33 | Mid-calf, under jeans |
| Rain boot (tall) / wellington | 12-16 | 30-41 | Upper calf |
| Knee-high | 14-18 | 36-46 | One to two fingers below the knee |
| Over-the-knee | 20-24 | 51-61 | Lower to mid thigh |
| Thigh-high | 25+ | 64+ | Upper thigh |
The same style ends at different points on different legs. A 15 in shaft is knee-high on someone 5 ft 2 in (157 cm) but ends at the upper calf, a few inches below the knee, on someone 5 ft 10 in (178 cm). Before buying tall boots, measure your own leg: sit with your foot flat and measure from the floor at the heel to the back of the knee, then subtract about 1 in (2.5 cm) so the top does not dig in when you bend the knee.
Calf circumference: standard, wide and extra-wide
Tall boots list the circumference of the shaft at its widest point, usually the top opening. Measure your calf at its widest part, standing, and add room for the trousers or socks you will tuck in.
| Calf fit | Shaft circumference (in) | Shaft circumference (cm) |
|---|---|---|
| Slim / narrow calf | 12-13.5 | 30-34 |
| Standard | 14-15 | 36-38 |
| Wide calf | 16-17.5 | 41-44 |
| Extra-wide calf | 18-20+ | 46-51+ |
These are the ranges most brands use, not a standard, and circumference rises a little with foot size inside one model. Allow about 0.5-1 in (1-2.5 cm) over your calf for leggings or tights, and 1-1.5 in (2.5-4 cm) for jeans tucked in. Stretch leather, elastic gores and back zips with gussets add roughly an inch of give.
Boot size conversion
Boot lengths use the same scales as shoes. The quick rules: US men's = UK + 1, US women's = UK + 2 (or + 2.5 at brands that set women's 1.5 above men's), and EU = roughly UK + 33 to 34.
| UK | EU | US men's | US women's | Foot length |
|---|---|---|---|---|
| 4 | 37 | 5 | 6 | 22.9 cm / 9.0 in |
| 5 | 38 | 6 | 7 | 23.7 cm / 9.3 in |
| 6 | 39-39.5 | 7 | 8 | 24.6 cm / 9.7 in |
| 7 | 40.5-41 | 8 | 9 | 25.4 cm / 10.0 in |
| 8 | 42 | 9 | 10 | 26.2 cm / 10.3 in |
| 9 | 43 | 10 | 11 | 27.1 cm / 10.7 in |
| 10 | 44.5 | 11 | 12 | 27.9 cm / 11.0 in |
| 11 | 45.5-46 | 12 | 13 | 28.8 cm / 11.3 in |
| 12 | 47 | 13 | 14 | 29.6 cm / 11.7 in |
| 13 | 48-48.5 | 14 | 15 | 30.5 cm / 12.0 in |
Every half size between these rows and the full EU lookup are in the shoe size chart; children's winter boots follow the kids' shoe size chart.
How boots should fit, by type
Hiking boots
Leave about ½ in (12 mm) between the longest toe and the end, enough that toes do not hit the front on a steep descent. With the boot unlaced, you should just fit a finger behind the heel. Fit them with hiking socks, late in the day, and expect most people to land half a size above their street shoe.
Work and safety-toe boots
Safety toe caps (tested to ASTM F2413 in the US and ISO 20345 in Europe) do not stretch or mold. The toes must have clearance inside the cap while standing and while crouched, so do not size down expecting the boot to give. Work boots commonly come in D (medium) and EE or EEE (wide) for men; if the toe cap presses on the little toe, choose a wider fitting rather than a longer size.
Western and cowboy boots
The instep should feel snug and the ball of the foot should sit at the widest part of the sole. New cowboy boots normally let the heel lift about ¼-½ in (6-12 mm) when walking; this reduces as the stiff sole breaks in. A heel that lifts more than that, or toes touching the end, means the wrong size.
Rain boots and wellingtons
Most come in whole sizes only. If you are a half size, go up and add a thicker sock or an insole. Measure your calf too: rubber does not stretch, and standard tall rain boots typically fit calves up to about 15-16 in (38-41 cm).
Ski and snowboard boots
Ski boots are sized in Mondopoint, the foot length in cm (ISO 9407). A 26.5 ski boot fits a 26.5 cm foot, roughly a UK 8.5 or US men's 9.5. Shells usually cover two half sizes, such as 26.0/26.5. Snowboard boots normally use US sizes. Both should fit tighter than street shoes, with toes lightly touching the front when you stand straight. The ski size guide covers ski lengths.
Measuring tips before you buy boots online
- Measure foot length standing, in the socks you will wear with the boots. Thick wool socks add 2-4 mm all round, which can be half a size.
- Measure the calf at its widest point and, for over-the-knee styles, the thigh at the height where the boot ends.
- Measure your leg height from the floor to the back of the knee if you want a knee-high boot to sit in a particular place.
- Check the instep. Pull-on boots without laces or zips have to slide over the instep (the top of the foot). A high instep is the usual reason a Chelsea or western boot will not go on even when the length is right.
- Compare with the listing. Product pages give shaft height, heel height and opening circumference for one reference size (often US women's 7 or 8 or men's 9); larger sizes are slightly taller and wider.
A boot that fits with a thin sock can be half a size short with a winter sock or an aftermarket insole. If you plan to use either, take them to the fitting. The sock size guide lists sock heights that clear each boot shaft, and the insole guide explains how much volume an insole takes up.
For boot-cut jeans, the leg opening needs to be about 16-18 in (41-46 cm) around to sit over a western or work boot shaft; see the jeans size guide for cut measurements.
Frequently asked questions
How high are mid-calf boots?
Mid-calf boots usually have a shaft of 8-12 in (20-30 cm) measured from the arch. On an adult that ends between the top of the ankle bone and the widest part of the calf. On a big kid (around youth size 5) a mid-calf winter boot is typically 7-9 in (18-23 cm) tall.
What is the difference between a three-quarter (calf-high) boot and a knee-high boot?
A three-quarter or calf-high boot stops below the widest part of the calf, usually 10-13 in (25-33 cm) of shaft. A knee-high boot reaches to just below the knee, usually 14-18 in (36-46 cm). The difference is about 4-5 in (10-13 cm).
Should boots be a size bigger than shoes?
Not as a rule. Fashion boots worn with thin socks take your shoe size. Winter, hiking and work boots worn with thick socks often need half a size more, and some work-boot brands already cut their lasts roomy. Try them on with the socks you will wear.
Are UK and US boot sizes converted the same way as shoes?
Yes. UK boot sizes are 1 below US men's and 2 below US women's, and UK 12 is about EU 47. Western and work boots are almost always sold in US sizes with a width letter.
How do over-the-knee boots fit the thigh?
Over-the-knee boots are sized by thigh as well as calf. Check the listed top-opening circumference against your thigh measured at the height where the boot ends, and look for stretch panels or a back lace if your thigh is above about 20 in (51 cm).