Banana Republic and Primark rarely share a wardrobe budget, but they often share a shopper — and the sizing handoff between them is stranger than the price gap suggests. Banana Republic sizes in US numerics (00–16) under its letters and is the tailored, true-to-size member of the GAP family. Primark sizes in UK numbers, where US size = UK size minus four, and has a well-earned runs-small reputation.
Here's the surprise: align the two charts by US size and they're broadly comparable — Primark trims a little smaller at the petite end, and actually edges larger around UK 14–16. The real difference isn't the chart, it's what the garments do with it. Below are both charts aligned by body measurement, the men's chart where the brands nearly agree, and the rules for switching without a return.
The short answer
The charts are close — but in the fitting room, Primark runs smaller
By the tape, this pair is more aligned than their reputations suggest. At a US 8, Primark's UK 12 fits a 91 cm (36") bust against Banana Republic's M at 36–37"; at a US 12, Primark's UK 16 (102 cm · 40") lands at the top of BR's L (38.5–40"). Only at the petite end does Primark cut clearly smaller — its UK 8 (83 cm · 32.5" bust) reads closer to BR's XS than to the S that a US 4 implies.
The garments are another matter. Banana Republic delivers its chart: true to size, tailored, with predictable quirks (roomy blouses, generous blazer shoulders, snug non-stretch trouser waists). Primark tends to run small against its own chart — sizing up in jeans, fitted dresses, and tailored shirts is standard advice, even from staff — and garment-to-garment consistency is loose. So convert your BR size to UK by adding four, then expect to go up one more in anything fitted at Primark.
Banana Republic vs Primark at a glance
| Banana Republic | Primark | |
|---|---|---|
| Sizing system | US numeric (00–16) mapped to alpha sizes | UK numeric (US size + 4); alpha sizes for men |
| Overall fit | True to size — tailored, standard-US cut | Runs small, sharpest in denim and fitted styles |
| Consistency | Reliable — chart and garment agree | Famously loose — identical items can fit differently |
| Where to adjust | Size down in flowy blouses and knits; blazers run generous in the shoulder | Size up in jeans, fitted dresses, and formal shirts |
| Chart coverage (women) | US 00–16 (XS–XL) | UK 4–20, i.e. US 0–16 |
Women's bust side by side, aligned by US size
Rows align by body measurement through each brand's published US conversion (Primark's UK size = US + 4; BR letters span two US sizes). Formats follow each source chart.
| US size | Primark size · bust | BR size · bust |
|---|---|---|
| 2 | UK 6 · 79 cm · 31" | XS (00–2) · 31–33" · 78.5–84 cm |
| 4 | UK 8 · 83 cm · 32.5" | S (4–6) · 34–35" · 86.5–89 cm |
| 6 | UK 10 · 87 cm · 34.5" | S (4–6) · 34–35" · 86.5–89 cm |
| 8 | UK 12 · 91 cm · 36" | M (8–10) · 36–37" · 91.5–94 cm |
| 10 | UK 14 · 96 cm · 38" | M (8–10) · 36–37" · 91.5–94 cm |
| 12 | UK 16 · 102 cm · 40" | L (12–14) · 38.5–40" · 98–101.5 cm |
Women's waist side by side, aligned by US size
Same alignment as above. Primark sits below BR at the small end and slightly above it from US 10 up.
| US size | Primark waist | BR waist |
|---|---|---|
| 2 | 62 cm · 24.5" | 24–26" · 61–66 cm |
| 4 | 66 cm · 26" | 27–28" · 68.5–71 cm |
| 6 | 70 cm · 27.5" | 27–28" · 68.5–71 cm |
| 8 | 74 cm · 29" | 29–30" · 73.5–76 cm |
| 10 | 79 cm · 31" | 29–30" · 73.5–76 cm |
| 12 | 85 cm · 33.5" | 31.5–33" · 80–84 cm |
Men's tops side by side
Chest measurements by letter — BR publishes body measurements, Primark publishes to-fit ranges. The two charts nearly mirror each other; BR runs slightly wider at L and XL.
| Size | BR chest | Primark chest |
|---|---|---|
| XS | 34–35" · 86.5–89 cm | up to 36" · 90 cm |
| S | 36–37" · 91.5–94 cm | 36–38" · 91–96 cm |
| M | 38–40" · 96.5–101.5 cm | 38–40" · 97–102 cm |
| L | 41–44" · 104–112 cm | 41–43" · 103–108 cm |
| XL | 45–48" · 114.5–122 cm | 44–46" · 112–117 cm |
Switching between Banana Republic and Primark
- Converting BR → Primark (women): add four to your US number for the UK label, then go up one more in Primark jeans, fitted dresses, and tailored shirts — that's where it runs small.
- Converting Primark → BR: subtract four from your UK size, and take BR at face value — its chart is honest. Just size down in flowy blouses and knits if you like a closer fit.
- Petite shoppers, take note: below roughly a US 6, Primark's chart genuinely runs smaller than BR's, so the runs-small effect compounds at the small end.
- Men can keep their letter at both stores — the chest charts nearly match — but Primark's garment-to-garment variation means checking the label measurements is still worth it.
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 Banana Republic size guide and the Primark size guide.
Banana Republic vs Primark sizing FAQs
Which runs smaller, Banana Republic or Primark?
In practice, Primark. The published charts are surprisingly close once you convert UK to US sizes, but Primark garments tend to run small against their own chart — especially denim and fitted pieces — while Banana Republic is reliably true to size. Add Primark's loose consistency and the safe bet is sizing up there, not at BR.
What Primark size should I buy if I wear a Banana Republic 8?
Start with a Primark UK 12 — that's the direct conversion, and its 91 cm (36") bust matches BR's M (36–37"). For Primark jeans, fitted dresses, or formal shirts, take the UK 14 instead; sizing up in those is standard advice.
How do UK and US sizes convert between these brands?
UK sizes run four numbers above US: Primark's UK 8 is a US 4, UK 12 is a US 8, UK 16 is a US 12. Banana Republic's letters then group the US numbers — XS is 00–2, S is 4–6, M is 8–10, L is 12–14, XL is 16.
Are the men's sizes the same at Banana Republic and Primark?
Very nearly. Both brands' M covers a 38–40" chest, and S, L, and XL line up within an inch or two — BR runs slightly wider at the top (its XL reaches 48" versus Primark's 46"). Keep your letter; the difference you'll feel is BR's tailored cut versus Primark's variable one.
Why does Primark fit unpredictably when its chart looks fine?
Consistency, not the chart, is Primark's weak spot — manufacturing tolerances vary across factories and batches, so two copies of the same garment can measure differently. Banana Republic's production is far more uniform. At Primark, when fit matters, check the actual measurements on the label rather than trusting the size.
