Size Guide
Gap & Old Navy Size Chart & Fit Guide: Does Gap & Old Navy Run Small?
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Quick verdict
Gap and Old Navy tend to run big. Both are classic American vanity-sized brands cut with generous ease, and Old Navy is commonly reported as the roomier of the two. Most shoppers can take their usual US size at Gap, while many go one size down at Old Navy — especially in stretch denim, which relaxes further with wear.
How Gap & Old Navy fits by category
Tops & sweaters
Both brands cut to a relaxed American block, and vanity sizing is part of the house style: a Gap medium commonly measures more generous than a medium at slimmer European labels. Old Navy tees and sweaters are widely reported as the roomier of the two, with extra ease through the chest and waist, so shoppers who want a trimmer line often drop a size there while staying true to size at Gap.
Denim & pants
Gap denim tends to run comfortable at the labeled waist, and because most washes carry stretch, jeans commonly relax further after a few wears. The frequent advice from repeat buyers is to take the snugger of two sizes in stretch denim and let it break in. Old Navy jeans tend to start out even roomier, so many shoppers report going down a full size from their Gap number, especially in high-stretch fabrics.
Dresses & outerwear
Dresses, chinos-adjacent skirts, and outerwear follow the same generous pattern. Gap jackets are cut with layering room built in, so sizing up is rarely necessary unless you want an oversized look. Old Navy's dresses and coats tend to be the loosest-fitting pieces in either lineup. Many shoppers find flowy Old Navy styles wear best a size below their usual.
Size conversion charts
The tables below are standard international conversions, not Gap & Old Navy-specific garment measurements. Cuts and fabrics vary between styles, so check Gap & Old Navy's official size chart for exact garment measurements before you order.
Women's clothing: standard international conversion
Standard conversions; individual brands vary by cut and fabric.
| Alpha | US | UK | EU |
|---|---|---|---|
| XS | 0–2 | 4–6 | 32–34 |
| S | 4–6 | 8–10 | 36–38 |
| M | 8–10 | 12–14 | 40–42 |
| L | 12–14 | 16–18 | 44–46 |
| XL | 16–18 | 20–22 | 48–50 |
| XXL | 20–22 | 24–26 | 52–54 |
Men's tops: standard international conversion
US and UK men's sizes use the same chest-inch base; EU adds roughly 10.
| Alpha | Chest (US/UK, in) | EU |
|---|---|---|
| XS | 32–34 | 42–44 |
| S | 34–36 | 44–46 |
| M | 38–40 | 48–50 |
| L | 42–44 | 52–54 |
| XL | 46–48 | 56–58 |
| XXL | 50–52 | 60–62 |
How to choose your size at Gap & Old Navy
- Treat the two brands separately: a Gap medium and an Old Navy medium are cut from different blocks; many shoppers wear a size smaller at Old Navy.
- Buy stretch denim snug: jeans with stretch commonly loosen at the waist and seat within a few wears, so take the tighter of two sizes.
- Between sizes? Go down: with generous vanity sizing, the smaller size is usually the safer bet at both brands.
- Check the fit name, not just the size: both brands sell the same size across slim, straight, and relaxed cuts, and the cut changes the fit more than one size step does.
Gap & Old Navy sizing FAQ
Does Old Navy run big?
It has that reputation, yes. Old Navy is commonly reported to run roomier than most US brands, and often roomier than sister brand Gap in the same labeled size. If you're between sizes at Old Navy, the smaller one is usually the safer pick.
Does Gap run big or small?
Gap tends to run big relative to European and Asian brands, a legacy of classic American vanity sizing, though it's commonly reported to sit a touch closer to true-to-size than Old Navy. Most shoppers can take their usual US size at Gap without surprises.
Is Gap and Old Navy sizing the same?
They're sister brands under the same parent company, but their fit blocks aren't identical. Old Navy is the budget line and tends to cut with more ease, so a medium at Old Navy commonly fits looser than a medium at Gap. Many shoppers wear one size at Gap and the size below at Old Navy.
Should I size down in Gap jeans?
In stretch denim, many shoppers do. Gap's stretch jeans commonly loosen through the waist and seat with wear, so buyers who take the snugger size on day one tend to be happier after a week of wearing. Rigid, non-stretch washes hold their shape, so stay true to size in those.
Do Old Navy jeans stretch out?
High-stretch styles commonly do: shoppers frequently report the waist and thighs relaxing noticeably after a few wears without washing. Since Old Navy denim also tends to start out generous, going down one size in stretch fits is the advice most repeat buyers give.
Keep reading
- Levi's size chart & fit guide
- Uniqlo size chart & fit guide
- Vanity sizing explained: why labels keep getting bigger
- International size conversion charts
- How to measure yourself at home
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