How to fit insoles into trainers (and other footwear)

A gel insole only does its job when it sits flat inside the shoe, in the right place and at the right length. Fitting one into a pair of trainers takes a couple of minutes, but the details matter: take the original insole out first, use it as a template, and trim a little at a time along the cutting guide. Here is the process step by step, plus what to do about boots, close-fitting shoes and footwear with no removable insole.

In this article

1. Before you start: check the footwear
2. Fitting an insole into trainers, step by step
3. Trimming to size with the cutting guide
4. Boots, tight shoes and footwear with a fixed insole
5. Signs the insole is not sitting right
6. Common mistakes and a quick checklist

Before you start: check the footwear

Not every shoe will take an extra insole comfortably. Before you trim anything, look at the footwear you intend to use it in.

• Does the shoe have a removable insole? If it lifts out, you have both the space you need and a ready-made template.
• How much room is there in front of the toes? Press down on the toe box with the shoe on: there should still be a little space at the end.
• Can you adjust the fit? Laces, straps and buckles give you some margin. A slip-on shoe gives you none, and a shoe that is already snug with your usual socks is unlikely to take a gel insole.
• Is the footbed glued down? Some trainers and most smart shoes have a fixed footbed, which changes the approach.

One thing worth settling now: Footgel insoles are made in European (EU) sizes, and each one has a cutting guide with marked lines at the toe end so you can take it down to the length you need. The size on the packaging is your starting point; the cutting guide gives you the final fit. You can see the full range in the Footgel catalogue.

Fitting an insole into trainers, step by step

1. Take the original insole out

Loosen the laces completely and open the shoe as far as it will go. Lift the original insole from the heel end and pull it forward; if it resists at the front it may be lightly tacked down, so work it free gently. Keep it: it is your template.

2. Check the shoe takes the new insole without tightening the fit

Drop the new insole into the shoe before you do anything irreversible. Put the shoe on with your usual socks, lace it as normal and stand up. You are after a fit that feels supported rather than compressed, with room to move your toes and the heel sitting down in the back of the shoe. If it feels tight straight away, stop there: trimming the length will not solve a lack of height or width.

3. Use the original insole as a template

Lay the original insole on top of the new one, heel against heel and lined up down the centre, then draw around its toe end with a pen. Only the front is ever marked: the heel and the arch section are never trimmed.

Then cut along the line that matches your EU size, or the one you have just drawn, as described in the next section.

4. Seat it flat and check for creases

Slide the insole in heel first, push it back until it meets the back of the shoe, then press it down along the arch and towards the toes. Run a finger round the edge: it should lie flat, with no ridge riding up the side and no fold under the ball of the foot. An insole that refuses to lie flat is usually still a touch too long.

5. Walk on it

Fit both shoes, even if only one foot bothers you, and walk on a hard floor for a few minutes. Your heel should stay down as you step, your toes should have room, and nothing should rub. Then try the stairs: that is where a badly seated insole gives itself away.

Trimming to size with the cutting guide

The cutting guide is a set of lines marked across the toe end, each corresponding to a size. Find the one that matches your EU size and cut along it. A few rules make the difference between a clean fit and a wasted insole.

• Trim a little at a time. Cutting cannot be undone, so it is better to remove two millimetres twice than four millimetres once.
• Cut from the toe end only. The heel cup and the arch section are shaped to sit under particular parts of the foot.
• Follow the curve of the line rather than cutting straight across. A square toe end pushes into the front of the shoe and lifts the insole.
• Use sharp scissors and cut in long, continuous strokes. Short snips leave a jagged edge that catches inside the shoe.
• Put the insole back in the shoe between cuts and stand up. Checking twice saves you from over-trimming.

If your foot falls between two lines on the cutting guide, start with the longer one. A few millimetres too long can always be trimmed again; too short leaves a gap at the front and the insole slides forward.

Everyday comfort, step by step

An everyday gel insole for men, designed to bring greater comfort and cushioning to your everyday footwear and to relieve pain in the feet and joints.

• Tested by UMANA Biomecánica
• Made in Spain

View Footgel Daily Use Men

Boots, tight shoes and footwear with a fixed insole

Footwear with no removable insole

When the footbed is glued in, you can still lay the new insole on top, but you are adding height without taking any away. In roomy footwear, such as work boots worn with thick socks, that is often fine. In anything close-fitting it makes the shoe too tight, and a pair with a removable insole is the better choice.

Walking boots, work boots and other high-cut footwear

Tall boots are easier than they look, as long as you open them properly. Unlace them down to the bottom eyelets, fold the tongue forward and slide the insole in heel first, pushing it back with a long-handled shoehorn. Then check the heel end is flat rather than folded against the back of the boot. For long shifts on hard floors, Footgel Works is designed for work boots and safety footwear, while Footgel Trekking is made for long routes and uneven ground.

Very close-fitting footwear

Football boots, cycling shoes, smart shoes and anything with a narrow toe box leave very little spare volume. Always take the original insole out first, and accept that some pairs will not take an extra layer at all: a shoe that presses on the top of the foot does not become comfortable through use.

Two insoles at once: don't

Stacking a gel insole on top of the original one is a common shortcut and a poor idea. It raises the foot so far that the heel lifts out of the shoe, the toes press into the front and neither layer sits flat. One insole per shoe, original removed.

Signs the insole is not sitting right

Take the shoe off and look again if you notice any of the following.

• Your toes press against the end of the shoe, or curl up when you stand.
• Your heel lifts out of the shoe as you walk, even with the laces done up firmly.
• You feel rubbing or a hot spot, usually on the top of the foot or around the heel.
• The insole creases under the ball of the foot, or slides forward during the day.
• You get pins and needles, or keep loosening the laces.

Nearly all of these have one of two causes: the insole is still slightly too long, or the footwear has no spare volume. Trim again in small steps for the first, change to a roomier pair for the second.

How long does it take to get used to a new insole?

A new insole changes how your foot sits inside the shoe, so it is sensible to build up gradually: a few hours a day at first, then longer walks or a full shift once it feels natural. Being aware of the insole under your arch in the first days is normal; sharp pain or rubbing is not, and means something needs adjusting. If discomfort continues once the insole is fitted correctly, or you have foot pain that does not settle, it is worth speaking to a healthcare professional.

Common mistakes and a quick checklist

• Leaving the original insole in the shoe. This is the most common reason a correctly sized insole feels too tight.
• Cutting before trying, cutting straight across, or cutting anywhere but the toe end.
• Fitting one shoe only. An insole in one shoe alone leaves you standing unevenly.
• Wearing them for a full day straight away instead of building up.

The short version: original insole out, new insole in, heel pushed right back, edges flat, no creases, toes with room, heel staying down as you walk. If you are choosing an insole for a particular activity or for long hours on your feet, the Footgel catalogue groups the models by use.