Insole Sizes: Length by Shoe Size, Trimming, Thickness and Arch Height
Replacement insoles have to match two things: the inside length of your shoe and the room left over for your foot once the insole is in. This page gives standard insole lengths for every adult size, explains trim-to-fit ranges, and shows how thickness and arch height change the fit.
An insole is about as long as the shoe's last, roughly 1.7 cm (⅔ in) longer than the foot. A men's US 9 / women's US 10 (UK 8, EU 42) insole is about 11 in (27.9 cm) long, and each full size adds ⅓ in (8.5 mm). Trim-to-fit insoles cover a range of sizes and are cut down to match your existing insole.
- Men's US 9 insole
- 11 in (27.9 cm)
- Women's US 7 insole
- 10 in (25.4 cm)
- Per full size
- +⅓ in (8.5 mm)
- ¾-length insole
- about 72% of foot
On this page
Insole length by shoe size
The lengths below are standard last lengths, which is what a full-length insole should match. Measure your shoe's own insole if you can; pointed toes and roomy work boots run longer, rounded athletic shapes close to these figures.
| US men's | US women's | UK | EU | Insole length (in) | Insole length (cm) |
|---|---|---|---|---|---|
| 4 | 5 | 3 | 35.5 | 9.33 | 23.7 |
| 5 | 6 | 4 | 37 | 9.67 | 24.6 |
| 6 | 7 | 5 | 38 | 10.0 | 25.4 |
| 7 | 8 | 6 | 39-39.5 | 10.33 | 26.2 |
| 8 | 9 | 7 | 40.5-41 | 10.67 | 27.1 |
| 9 | 10 | 8 | 42 | 11.0 | 27.9 |
| 10 | 11 | 9 | 43 | 11.33 | 28.8 |
| 11 | 12 | 10 | 44.5 | 11.67 | 29.6 |
| 12 | 13 | 11 | 45.5-46 | 12.0 | 30.5 |
| 13 | 14 | 12 | 47 | 12.33 | 31.3 |
| 14 | 15 | 13 | 48-48.5 | 12.67 | 32.2 |
Each insole is about 1.7 cm (⅔ in) longer than the foot it fits, the usual allowance between foot and last. So a quick check is foot length plus 1.7 cm. The size conversions match the shoe size chart; US women's here is UK + 2, and brands that use UK + 2.5 shift the women's column by half a size.
Trim-to-fit size ranges
Most over-the-counter insoles are sold in ranges and cut down at the toe. Ranges span anything from about two full sizes to six, and each insole is made at the length of the largest size in its range and trimmed for the smaller ones.
- Pick the range that contains your size near its upper end if you can. You then trim little or nothing, and the arch sits where the maker intended.
- Be wary of trimming a shaped arch insole by more than about 1.5 cm (⅝ in), or two sizes. Its arch is placed for the longest size in the range, so heavy trimming leaves the arch peak too far forward for your foot. Flat cushioning insoles can be cut down further.
- Unisex ranges are usually labeled in men's sizes with women's alongside, for example "men's 7-9 / women's 8-10".
- Remove the original insole from the shoe. If it is glued in, see the ¾-length option below.
- Align the heels of the old and new insoles, one on top of the other, and press them together.
- Trace the toe outline of the old insole onto the new one with a pen.
- Cut about 2 mm outside the line with sharp scissors, test in the shoe, then trim further if the insole buckles or rides up at the toe.
- Check both shoes: left and right originals are not always identical, and your feet may differ too.
Full-length, ¾-length and heel inserts
The ball of the foot sits about 72% of the way from the heel to the toe tip (the "arch length" on a Brannock Device). Partial insoles stop just behind it.
| Type | Length | Example length | Best for |
|---|---|---|---|
| Full length | Whole shoe | 11 in (27.9 cm) | Athletic shoes and boots with a removable insole |
| ¾ length | Heel to just behind the ball | about 7.4 in (19 cm) | Dress shoes, snug shoes, fixed insoles |
| Heel cup / heel pad | Rear third of the foot | about 3-4 in (8-10 cm) | Heel cushioning, slight lift, heel slip |
| Metatarsal pad | Small pad behind the ball | about 2 in (5 cm) | Spreading pressure under the forefoot |
A ¾-length insole for other sizes is about 72% of the foot length: 6.7 in (17 cm) for a women's US 7 and 7.9 in (20 cm) for a men's US 11.
Insole thickness and shoe volume
Every millimeter of insole takes room from the foot. Shoe makers' own insoles are typically a few millimeters thick, and many replacements are thicker, especially under the heel.
| Profile | Forefoot thickness | Heel thickness | Fits in |
|---|---|---|---|
| Low volume / slim | 1-3 mm | 3-6 mm | Dress shoes, cycling and soccer boots, tight trainers |
| Medium volume | 3-4 mm | 6-9 mm | Running and walking shoes |
| High volume / cushioned | 4-6 mm | 9-12 mm | Hiking and work boots with room to spare |
Compare the new insole with the one it replaces, not with nothing. If the new one is 2-3 mm thicker at the forefoot, a shoe that was just right will feel tight over the toes; that is about the difference between two widths. Thick insoles also raise the heel in the heel counter, which can cause rubbing at the back of low-cut shoes.
Replacement insoles go in place of the shoe's insole, not on top of it. Stacking two insoles is the most common reason a new insole feels too tight or pushes the heel out of the shoe.
Arch height: low, medium and high
- Low arch: the wet footprint shows almost the full width of the foot through the middle. Look for a low or medium arch support with a firm heel cup; very tall arches press uncomfortably.
- Medium arch: about half the width of the midfoot shows. Most "neutral" insoles are built for this.
- High arch: the footprint shows a thin band, or heel and forefoot with a gap between. A higher, contoured arch fills the space under the foot and spreads the load.
Persistent foot pain, diabetes-related foot problems or a large difference between the feet call for a podiatrist rather than an off-the-shelf insole. Custom orthotics are made from a cast or scan of the foot and are built to fit the shoe they go in.
Insoles in boots, sandals and kids' shoes
- Boots: winter and work boots usually have room for a medium or high-volume insole. Check toe clearance inside a safety toe cap after fitting one; the boot sizing guide covers this.
- Sandals: loose insoles do not stay in open footwear. Choose a sandal with a contoured footbed instead (see sandal sizes).
- Children: insoles for kids are sold in children's sizes; trim them to the shoe's original insole, which is also the best way to check growing room. See the kids' shoe size chart.
- Socks: switching from thin to thick socks uses about as much room as a thin insole. Fit new insoles with the socks you will wear.
Frequently asked questions
Should I buy insoles in my shoe size?
Yes, buy the range that includes your shoe size, then trim to the shape of the insole that came with the shoe. Shoe interiors differ by up to about 1 cm between brands of the same size, so the original insole is a better template than the size marking.
Do I need a bigger shoe size for insoles?
Only if the new insole is thicker than the one it replaces. A cushioned or high-arch insole that adds 3-5 mm under the forefoot can make a snug shoe tight; half a size up, or a wider fit, restores the room.
How do I trim insoles to the right size?
Take out the shoe's original insole, lay it on top of the new one with the heels aligned, and draw around the toe. Cut a little outside the line, test in the shoe and trim again. Trim only the toe end; the heel cup and arch must stay where they are.
What is a ¾-length insole for?
A ¾ insole supports the heel and arch and stops just behind the ball of the foot, so it adds no thickness in the toe box. It suits dress shoes, tight-fitting shoes and shoes whose original insole cannot be removed.
How do I know my arch type for insoles?
Wet your foot and stand on a piece of card or a dark tile. A footprint that is almost full width through the middle suggests a low arch; a thin band or a gap suggests a high arch; about half the width is a medium arch.