Buying shoes online shouldn’t be a guessing game. That is why at Equiplix we dedicated a whole section to sports footwear. While both Adidas and Nike dominate the market, their fit philosophies are worlds apart.
The Quick Answer: * Which is more true to size? Adidas generally aligns closer to standard US sizing.
- Which runs narrower? Nike is notorious for a narrow, snug fit, especially in the midfoot.
- Which runs smaller? Nike typically runs 1/2 size smaller than Adidas.
- When to size up? Always size up 1/2 size in Nike running and training shoes. Stay true to size in most Adidas models, except for specific narrow lifestyle silhouettes.
QUICK VERDICT
Best for narrow feet: Nike
Best for wide feet: Adidas
Best true-to-size: Adidas
Brand that runs smaller: Nike
Who should size up: Nike buyers and runners needing toe room.
Who should stay true to size: Most Adidas buyers (except in Samba/Gazelle).
BRAND FIT AT A GLANCE
| Feature | Adidas | Nike |
| Length Fit | True to standard | Often runs short |
| Width Fit | Medium to Wide | Narrow to Medium |
| Toe Box Room | Generous/Square | Shallow/Pointed |
| Arch Fit | Neutral/Moderate | Higher/Snug |
| True-to-Size Accuracy | High | Low (Size up often) |
| Best for Wide Feet | Yes | No (Unless “Wide” version) |
| Best for Narrow Feet | No | Yes |
| Running Shoe Fit | Relaxed/Standard | Performance/Tight |
| Lifestyle Sneakers | Varies (Samba is narrow) | Generally Narrow |
SIZING BREAKDOWN
Adidas Sizing Explained
Adidas uses a more consistent, slightly wider last (the foot mold). If you wear a US 10 in dress shoes, a US 10 in an Adidas Ultraboost or Duramo will likely fit perfectly. However, their lifestyle “Terrace” shoes like the Samba and Gazelle have a lower volume and narrower profile. If you have wide feet, these specific models may require a half-size increase.
Nike Sizing Explained
Nike designs for a “locked-in” feel. This performance-first approach means shoes like the Nike Pegasus and Nike Revolution wrap tightly around the foot. Most users find that Nike runs small across the board. If you are transitioning from Adidas to Nike, expect to go up at least a half size to achieve the same internal length.
Does Adidas Run Bigger Than Nike?
Yes. In a direct Adidas vs Nike shoe size comparison, Adidas almost always offers more internal volume. An Adidas size 9 is physically larger than a Nike size 9. This is why many shoppers feel they “size down” for Adidas, when in reality, they are simply wearing their actual size, while Nike requires “sizing up.”
Which Brand Fits Narrow vs Wide Feet Better?
- Wide Feet: Adidas is the clear winner. The Adidas Ultraboost knit upper and wider sole flare provide a stable, non-constrictive base.
- Narrow Feet: Nike is the gold standard. Models like the Nike Metcon or Nike Air Force 1 provide the lateral support narrow-footed athletes need without excessive sliding.
COMPARISON OF POPULAR MODELS SIZING
| Model | Runs Small/Large/True | Best Foot Type | Size Recommendation |
| Adidas Ultraboost (see prices) | True to Size | Wide / Neutral | Buy your normal size |
| Adidas Samba (see prices) | Runs Narrow | Narrow | Size up 1/2 for wide feet |
| Nike Air Force 1 (see prices) | Runs Large | Wide / Neutral | Size down 1/2 |
| Nike Pegasus (see prices) | Runs Small | Narrow | Size up 1/2 |
| Nike Metcon (see prices) | Runs Narrow | Narrow | Size up 1/2 |
| Adidas Duramo (see prices) | True to Size | Wide | Buy your normal size |
HOW TO CHOOSE YOUR PERFECT SIZE
- Running Shoes: Your feet swell during runs. In Nike vs Adidas running shoe fit, always prioritize a thumb’s width of space in the toe box. This usually means sizing up 1/2 in Nike.
- Training Shoes: For lifting (like the Nike Metcon), you want a snug fit for stability. Don’t go too large or your heel will slip.
- Wide Feet: If you must buy Nike, look specifically for “Extra Wide” (4E) versions. Otherwise, stick to Adidas.
- Sock Thickness: If you wear thick cushioned socks, Adidas’s extra volume will accommodate them better than Nike’s slim profile.
Best Nike for True-to-Size Fit: Nike Air Force 1
- Quick Verdict: The rare Nike that doesn’t run small; in fact, it runs a bit big.
- Pros: Iconic style, durable leather.
- Cons: Heavy, can feel clunky.
- Who it’s for: Casual wearers and those with slightly wider feet.
Best Adidas for Wide Feet: Adidas Ultraboost
- Quick Verdict: The king of comfort with a stretchy Primeknit upper.
- Pros: Massive energy return, accommodates wide feet easily.
- Cons: Expensive.
- Who it’s for: Runners and people on their feet all day.
Best Budget Nike: Nike Revolution
- Quick Verdict: Great entry-level runner, but fits very tight.
- Pros: Lightweight, affordable.
- Cons: Very narrow midfoot.
- Who it’s for: Narrow-footed beginners. Sizing Tip: Size up 1/2 full size.
WHICH ONE SHOULD YOU PICK?
It will depend on 2 factors: whether you want a reliable, true-to-size fit with room for your toes to breathe. The other factor is whether you have narrow feet or prefer a snug, athletic wrap. Here is the final take:
Choose Adidas if…
- You have wide feet or prefer a roomier toe box.
- You want to buy your “true” size without guessing.
- You prefer a softer, more flexible upper (Primeknit).
Choose Nike if…
- You have narrow or “standard” feet.
- You prefer a snug, performance-locked feel.
- You don’t mind sizing up 1/2 size to get the right length.
FAQs
Yes, typically by a half size. A Nike US 10 usually feels like an Adidas US 9.5.
Only in lifestyle models like the Samba or Gazelle if you have wide feet. Most Adidas performance gear is true to size.
Generally, yes. Nike uses a narrower last, making them better for slim feet and worse for wide feet.
Nike uses different “lasts” for different sports. A basketball shoe will fit tighter than a lifestyle sneaker even in the same size.
