Race boots are cut far closer than a trainer, on a thin sole, so half a size makes a real difference to how the pedals feel. Start with a tape measure rather than the size you take on the high street.
Measure your foot
Two minutes with a sheet of paper gets you closer than any conversion chart.
1Stand on paper against a wallHeel touching the skirting, weight on the foot. Sitting down gives you a shorter reading than standing.
2Mark the longest toeNot always the big toe. Mark the paper, then measure heel to mark in centimetres.
3Do both feetMost people have one foot a few millimetres longer. Work from the bigger one.
4Wear the socks you will drive inNomex socks are thicker than everyday ones and they take up real room in a boot cut this close.
Foot length to size
This is the anchor. Sparco and OMP both publish foot length against their sizes and the two never disagree by more than three millimetres, so a 28.3 cm foot is an EU 43 either way.
Alpinestars, Sabelt and MOMO do not publish foot lengths. Use the EU column here to get into the right area, then read your UK size off the cross-brand table below.
The same UK size, five different EU numbers
Sparco, OMP, Sabelt and MOMO all run the same ladder. Alpinestars run their own, with four extra half steps (40.5, 42.5, 43.5 and 45.5) that the others do not have. From UK 7 upwards their EU numbers stop lining up.
A dash means that brand does not make that size, not that it is out of stock. Sparco and OMP go to EU 48, Alpinestars to EU 49 on the Radar V2, Sabelt to EU 48 and MOMO to EU 46 on the boots we carry.
So which number do you order by?The UK size. It is the one we have checked against each brand’s own ladder for every product on the site, and it never varies by more than half a size between them. The EU number printed on the box will not always match across brands for the same UK size, because Alpinestars carry half sizes the others do not. If you have been looking at Alpinestars’ own website, note that their UK column runs half a size above the UK convention every UK retailer uses, ours included.
Full charts by brand
SparcoEU 36 to 48. Foot length published for every size.▼
OMPEU 36 to 48. Same UK ladder as Sparco.▼
AlpinestarsEU 37 to 49. Their own ladder, with four half sizes the others do not offer.▼
EU and US are Alpinestars’ own figures. The UK column is the UK retail convention, checked against three UK retailers, and it is what our listings carry. Alpinestars’ own website labels each of these half a size higher in UK.
SabeltEU 38 to 48. Same ladder as Sparco and OMP.▼
Sabelt do not publish a UK conversion table. They state their sizes follow the EU standard, and the UK labels on all four Sabelt boots we stock match Sparco’s and OMP’s ladder exactly.
MOMOEU 38 to 46 on the boots we carry.▼
From the chart published by Brown & Geeson, MOMO’s UK distributor.
How a race boot should fit
Snug, not roomy
You want your toes close to the end with no sliding at the heel. A boot with growing room moves on the pedal, and you feel it on a heel and toe downshift long before you feel it walking to the car. If you land exactly between two sizes, take the larger one and let a thicker sock take up the difference.
The sole is meant to be thin
There is no cushioning or arch support in the way a trainer has, because the whole point is feeling the pedal through the sole. A race boot that feels flat and hard standing in the showroom is doing its job. It is not a walking boot and it will not become one.
Wide feet
A knitted upper gives more than a stiff leather one. Alpinestars build the Supertech on a fully knitted upper specifically so it takes the shape of the foot, and that is the one to look at first if a leather boot has pinched you across the ball before. Tell us if width is your problem and we will point you at the right shells.
Buying boots and a suit together?Measure in one session, in your fireproof underwear and socks. It is the same half hour and it stops the two orders disagreeing with each other.
Sparco from sparco-official.com. OMP from the size chart on their Tecnica shoe product page. Alpinestars EU and US from their Supertech product page, UK from the UK retail convention checked against three UK retailers on 1 August 2026. MOMO from Brown & Geeson, their UK distributor. Sabelt from the ladder on the boots we stock. All checked 2 August 2026. If a chart in the box disagrees with this page, the box wins and we would like to know.
