Old Navy and Banana Republic sit at opposite ends of the same family. Both are Gap Inc. brands, both use US alpha sizing, and their women's bust charts are nearly carbon copies — Old Navy's M fits a 36–37" bust and so does Banana Republic's. If sizing were only about charts, you could swap labels between the two stores without a second thought.
You can't, because the garments tell a different story. Old Navy is the budget arm with the family's most generous cut — finished pieces frequently measure a size or more over the label — while Banana Republic is the dressed-up sibling with the most tailored, standard-US fit of the group, mostly delivering exactly what its chart promises. Here are the charts side by side and the adjustments that actually matter when you move between them.
The short answer
Banana Republic fits smaller — the charts nearly match, but Old Navy's generous cut and BR's tailoring pull the garments apart
On the women's side, the published body measurements are almost interchangeable: identical bust ranges from XS through M, near-identical hips, with Banana Republic allowing about an inch more waist per letter (its M fits a 29–30" waist against Old Navy's 28–29"). The difference you feel in the fitting room comes from the cut: Old Navy sizes generously — independent tests have found garments measuring well over the label — while Banana Republic's tailored blocks run true to size.
On the men's side, even the charts diverge: Old Navy's letters sit a chest size higher across the board — its M covers 39–41" against Banana Republic's 38–40", and its L covers 43–45" against BR's 41–44". Net effect in both departments: the same letter is the roomier garment at Old Navy, and the safest conversion is to trust your measurements, not the shared family name.
Old Navy vs Banana Republic at a glance
| Old Navy | Banana Republic | |
|---|---|---|
| Place in the Gap family | Budget arm — the most generous cut of the three sisters | Dressed-up arm — the most tailored of the three |
| Overall fit | Runs large; garments often measure over the label | True to size; delivers what the chart promises |
| Chart vs reality | Vanity sizing is real — fitted pieces run a size big | Charts are detailed and map cleanly to numeric sizes |
| Where to size down | Fitted tops, dresses, and jeans — for a fitted look | Flowy blouses, knits, and blazers (generous shoulders) |
| Watch out for | Stretch denim that relaxes further with wear | Non-stretch tailored trousers running snug at the waist |
Women's bust and waist side by side
Body measurements from each brand's published chart, compared at the same letter. Bust ranges are near-identical; Banana Republic allows roughly an inch more waist per letter. Hips match almost exactly through L.
| Size | Old Navy bust | Banana Republic bust | Old Navy waist | Banana Republic waist |
|---|---|---|---|---|
| XS | 31–33" · 78.5–84 cm | 31–33" · 78.5–84 cm | 23–25" · 58.5–63.5 cm | 24–26" · 61–66 cm |
| S | 34–35" · 86.5–89 cm | 34–35" · 86.5–89 cm | 26–27" · 66–68.5 cm | 27–28" · 68.5–71 cm |
| M | 36–37" · 91.5–94 cm | 36–37" · 91.5–94 cm | 28–29" · 71–73.5 cm | 29–30" · 73.5–76 cm |
| L | 38.5–40.5" · 98–103 cm | 38.5–40" · 98–101.5 cm | 30.5–32.5" · 77.5–82.5 cm | 31.5–33" · 80–84 cm |
| XL | 42.5–45" · 108–114.5 cm | 41.5" · 105.5 cm | 34.5–37" · 87.5–94 cm | 34.5" · 87.5 cm |
Banana Republic's numeric equivalents
Banana Republic publishes a clean alpha-to-numeric mapping; Old Navy's published chart lists alpha sizes with body measurements only. Use this to translate an Old Navy letter into BR's numeric sizes via the shared bust ranges above.
| BR size | US size | Bust |
|---|---|---|
| XS | 00–2 | 31–33" · 78.5–84 cm |
| S | 4–6 | 34–35" · 86.5–89 cm |
| M | 8–10 | 36–37" · 91.5–94 cm |
| L | 12–14 | 38.5–40" · 98–101.5 cm |
| XL | 16 | 41.5" · 105.5 cm |
Men's tops side by side
Body chest measurements at the same letter. Unlike the women's charts, the men's charts genuinely diverge — Old Navy's letters sit one to two inches higher per size.
| Size | Old Navy chest | Banana Republic chest |
|---|---|---|
| S | 37–38" · 94–96.5 cm | 36–37" · 91.5–94 cm |
| M | 39–41" · 99–104 cm | 38–40" · 96.5–101.5 cm |
| L | 43–45" · 109–114.5 cm | 41–44" · 104–112 cm |
| XL | 47–49" · 119.5–124.5 cm | 45–48" · 114.5–122 cm |
Switching between Old Navy and Banana Republic
- Don't carry your size between the sisters on trust: if you size down at Old Navy for a fitted look, switch back to your true size at Banana Republic — its tailored cut already fits close.
- Going from BR to Old Navy, drop a size in anything fitted — tops, dresses, jeans — and keep your usual size only in basics like tees and sweats.
- Men should compare chest numbers, not letters: an Old Navy M (39–41") overlaps Banana Republic's M and L, so check BR's chart before assuming the letter carries over.
- At Banana Republic specifically, go down a size in blazers if you're between sizes (the shoulders run generous) and check the waist measurement on non-stretch trousers, which run snug.
Measurements are based on each brand's published size charts and may vary by garment, fabric, and region. For the full charts and fit notes, see the Old Navy size guide and the Banana Republic size guide.
Old Navy vs Banana Republic sizing FAQs
Which runs smaller, Old Navy or Banana Republic?
Banana Republic, in practice. The women's charts are nearly identical on paper, but Old Navy cuts the most generously of the Gap Inc. sisters — garments often measure a size or more over the label — while Banana Republic is the most tailored and runs true to size. The same letter fits noticeably slimmer at BR.
Do Old Navy and Banana Republic use the same size chart?
Almost, for women: identical bust ranges from XS through M, with Banana Republic allowing about an inch more waist per letter. The men's charts differ more — Old Navy's M covers a 39–41" chest versus BR's 38–40", and the gap widens at L and XL.
I wear M at Old Navy — what size am I at Banana Republic?
Start with M — both brands' M fits a 36–37" bust, and BR's maps to a US 8–10. But because Old Navy garments run big, some shoppers who wear M at Old Navy are really an S body; if your fitted Old Navy pieces feel roomy, check your measurements against BR's chart before ordering.
Should I size down at Banana Republic like I do at Old Navy?
Not by default. Banana Republic runs true to size in suiting, dresses, and most pants, so take your true size there. The exceptions are its flowy blouses and knits, which are cut roomy through the body, and blazers, where going down a size gives a cleaner shoulder line.
Is GAP sizing the middle ground between these two?
Yes — within the family, Old Navy cuts most generously, GAP sits in the middle, and Banana Republic is the most tailored. The published charts look similar across all three, but the same label size feels progressively slimmer as you move up the price ladder.
