Convert Nike to Adidas Sizing Without Guessing

For most adults switching between Nike and adidas, start with the same US size in the same gender category. A Nike men’s 9 generally corresponds to an adidas men’s 9, and a Nike women’s 8 generally corresponds to an adidas women’s 8. Treat that as a chart-based starting point rather than a promise that every Nike and adidas model will fit alike.

Choose your gender category and Nike US size to see the adidas starting size and any available international-label comparison.

The Same US Size Is Usually the Right Starting Point

Nike and adidas assign similar measured foot lengths to the same US adult sizes. That is why a same-number conversion works better than trying to match the brands by reputation or by a UK or EU number printed on the box.

Your Nike Size	Adidas Starting Size
Men’s 7	Men’s 7
Men’s 8	Men’s 8
Men’s 9	Men’s 9
Men’s 10	Men’s 10
Men’s 11	Men’s 11
Men’s 12	Men’s 12
Women’s 6	Women’s 6
Women’s 7	Women’s 7
Women’s 8	Women’s 8
Women’s 9	Women’s 9
Women’s 10	Women’s 10
Women’s 11	Women’s 11

This does not require adding or subtracting a half size merely because the brand changes. If your established size is a Nike men’s 10, begin with an adidas men’s 10. If it is a Nike women’s 7, begin with an adidas women’s 7. Adjust only when the specific model, your foot width or the fit of the actual pair gives a reason to do so.

The brands’ official charts support that approach. Nike assigns men’s US 8 to a 10-inch foot, while adidas assigns men’s US 8 to a 25.5-centimeter foot. Those measurements are effectively the same after rounding. At men’s US 10, both charts correspond to about 27.1 centimeters. The complete ranges appear on the official Nike men’s footwear chart and adidas men’s footwear chart.

The women’s charts align in the same way at the cited example size. Women’s US 8 corresponds to approximately 24.6 centimeters at both brands. The official Nike women’s footwear chart and adidas women’s footwear chart provide their full ranges.

Foot length is the common reference behind the conversion. Brand names alone do not supply enough information to decide whether a shoe should be longer, shorter, wider or narrower. Start with the shared US-size position, then evaluate the shape and fit guidance for the model you intend to buy.

Matching UK Numbers Produces the Wrong Conversion

The same-number rule applies to US sizing within the same gender category. It does not carry over to UK labels. Nike and adidas attach different UK numbers to corresponding US men’s sizes.

US Men’s Size	Nike UK / EU	Adidas UK / EU
8	UK 7 / EU 41	UK 7.5 / EU 41 1/3
9	UK 8 / EU 42.5	UK 8.5 / EU 42 2/3
10	UK 9 / EU 44	UK 9.5 / EU 44
11	UK 10 / EU 45	UK 10.5 / EU 45 1/3

For example, Nike men’s US 9 is labeled UK 8 and EU 42.5. The corresponding adidas men’s US 9 is labeled UK 8.5 and EU 42 2/3. Matching the UK 8 labels instead would compare different positions in the two brands’ charts.

The EU labels do not follow one simple offset either. At men’s US 10, both brands use EU 44 even though Nike lists UK 9 and adidas lists UK 9.5. At men’s US 8, Nike uses EU 41 while adidas uses EU 41 1/3. A rule derived from one row cannot safely be applied to every other row.

For an overseas or resale listing, first identify three pieces of information: the brand, whether the number is US, UK or EU, and whether the listing uses men’s, women’s or youth sizing. A bare “9” does not identify a usable size system. A bare “42” identifies an EU-style label but still does not establish an identical Nike and adidas fit. The Italian and EU size 42 guide covers that distinction in more detail.

Use the US row or measured-foot-length row as the bridge between the brands. Do not find a Nike UK number and automatically order the same adidas UK number. In the cited men’s rows, the adidas UK label is a half size above the Nike UK label at the corresponding US size.

Box CM and JP Labels Are Not Foot Measurements

Centimeter information can look like a universal conversion, but the wording of the row matters. Nike explicitly warns that the CM/JP value printed on its boxes and labels differs from measured foot length. That means the number printed beside CM or JP should not automatically be treated as the physical length of the wearer’s foot.

adidas also separates “JP” from “heel-to-toe” in its chart. Those are distinct rows serving different labeling purposes. Copying a JP box value into a foot-length comparison can therefore put two unlike measurements side by side.

Measure the foot and use the row identified as foot length or heel-to-toe. If you are reading a box, resale photo or marketplace description, confirm whether the seller transcribed a regional label or supplied an actual foot measurement. The word “centimeters” by itself does not resolve that difference.

This distinction explains why the official US charts are more useful than comparing loose labels across brands. Nike men’s US 8 and adidas men’s US 8 align by the cited foot measurements even though the surrounding UK, EU and label conventions differ. The measurement row verifies the same-size starting point; the box label alone may not.

Men’s-To-Women’s Conversion Changes With the Brand

Keeping the same US number works only when the gender category also stays the same. Nike’s chart pairs men’s US 8 with women’s US 9.5, a 1.5-size difference. adidas pairs men’s US 8 with women’s US 9, a one-size difference.

That brand-specific difference matters for unisex releases and resale listings. A conversion remembered from a Nike pair should not be carried over automatically to an adidas pair. For the cited size, Nike men’s 8 converts to Nike women’s 9.5, while adidas men’s 8 converts to adidas women’s 9.

A listing described only as “size 8” is therefore incomplete when the shoe may be sold in men’s, women’s or unisex sizing. Find the category used on the original label or product page before comparing it with your own pair. The brand-level same-number rule does not repair a category mismatch.

Youth sizing adds another label system. Check whether a listing is marked GS rather than assuming that its number follows an adult men’s or women’s chart. The guide to what GS means and how GS sizes convert explains that category separately.

Air Force 1 Fit Can Override the Chart Conversion

Nike says the Air Force 1 generally runs big because of its roomy toe box. Its guidance recommends going half a size below your usual Nike size for many wearers. Someone who normally wears a Nike men’s 9 would therefore consider a men’s 8.5 in that model under Nike’s general recommendation, rather than treating every Nike 9 as interchangeable.

Nike gives a different starting point for wearers with wide feet: they can begin at their usual size. The company also notes that upper materials and editions can change the fit. The recommendation is model-specific and qualified, not evidence that every Nike shoe runs half a size large. Those details appear in Nike’s official Air Force 1 sizing guide.

This matters when an Air Force 1 is the pair being used as the reference for an adidas purchase. If your Air Force 1 is already half a size below your usual Nike size, copying the number printed on that shoe could make the adidas starting point too small. Recover your usual US size first, then consult the adidas model guidance.

For example, the useful question is not simply whether the number inside an Air Force 1 matches the number inside an adidas shoe. It is whether the Air Force 1 number reflects Nike’s model-specific downsize and whether the adidas model is intended to fit true to size. The two labels can differ even when both pairs fit the same wearer correctly.

Ultraboost Guidance Depends on the Version and Foot Width

adidas describes the Ultraboost 5 as true to size. Its guidance also says the Ultraboost 1.0 and 2.0 fit true to size for most people, while suggesting half a size up for wider feet. Other Ultraboost versions have their own notes in the official Ultraboost sizing guide.

That creates a different decision from the Air Force 1 recommendation. A wearer moving from a normally sized Nike model to an Ultraboost 5 can start with the same US size. A wearer using a downsized Air Force 1 as the reference should not necessarily copy the number printed in that shoe. A wearer considering an Ultraboost 1.0 or 2.0 and needing more width has adidas’s model-specific suggestion to consider.

None of those examples establishes that Nike runs larger than adidas overall. They show that Air Force 1 versus Ultraboost is a model comparison, not a reliable brand-wide conversion. The official chart determines the baseline; the model guidance determines whether that baseline should be adjusted.

Version names matter as well. Guidance for the Ultraboost 5 does not automatically establish the recommendation for every shoe carrying the Ultraboost name. Check the complete model designation in the listing rather than relying on a shortened family name.

Check Width and Volume Before Choosing a Longer Shoe

Once the chart and model guidance establish a starting size, judge the actual pair in separate areas: toe room, forefoot width, pressure over the top of the foot and heel hold. Those fit signals do not all point to the same remedy.

A shoe can have enough length while still feeling tight across the forefoot or over the top of the foot. Moving to a longer size may add space where it is not needed without resolving the shape mismatch. Conversely, a roomy toe box can make one model feel large even when another shoe from the same brand fits at the chart size.

Heel movement should also be considered separately from toe space. A pair that holds the forefoot but allows unwanted heel movement is not necessarily fixed by adding length. Evaluate the actual pair rather than reducing the decision to whether Nike or adidas supposedly “runs big.” The sneaker fit checklist provides a structured check for those areas.

The practical sequence is specific: match the US size within the same gender category, verify measured foot length if the regional labels differ, read the exact model’s fit guidance, and then assess the pair’s width, volume and heel hold. For most adult Nike-to-adidas switches, the first number to try remains the same US size.