What Is Sizing Like at Ralph Lauren?

By Ella Blake — Fashion Stylist | Tellar Fashion Hub — Always honest, unbiased & unsponsored

The honest answer to Ralph Lauren sizing is: it depends entirely on which line you're buying from, and getting those mixed up is one of the most common — and most expensive — mistakes in premium shopping. As a general rule, Lauren Ralph Lauren (the mainline womenswear) runs generously and you may want to size down; Polo Ralph Lauren is closer to true to size with a slim, modern cut; and Ralph Lauren Collection, the luxury tailoring line, runs small and is sized more like high-end French or Italian designer. One brand, three completely different answers. I've been shopping Ralph Lauren for years and I still pause before ordering anything new, because picking the wrong line's size logic will cost you a return every single time.

Understanding the Ralph Lauren Universe

Ralph Lauren isn't one brand — it's a constellation of labels sitting under one roof, each with a distinct aesthetic, price point, and, crucially, sizing philosophy. Before you even look at a size chart, you need to know which label you're actually shopping. Here's a quick breakdown:

Lauren Ralph Lauren — The main women's ready-to-wear line. Think polished casual, occasion dresses, knitwear, and classic separates. This is what most people are referring to when they say "Ralph Lauren." It runs slightly generous — the brand's own guidance says you may want to select one size smaller than usual.
Polo Ralph Lauren — The iconic preppy sport and casualwear line: polo shirts, Oxford shirts, chinos, knitwear, and casual dresses. Designed for a slim, modern fit. Generally true to size, but with a leaning towards the slimmer end — size up if you're between sizes or broad through the shoulders.
Ralph Lauren Collection — The luxury, runway-adjacent line. Structured blazers, silk dresses, and precision tailoring. This one runs genuinely small in the shoulders, chest, and waist. Treat it like European designer sizing and always check the measurements.
Double RL (RRL) — Vintage-inspired workwear and Western pieces. These vary significantly by garment — check individual measurements carefully.

💡 Before anything else: check the label name on the product page, not just "Ralph Lauren." Lauren, Polo, and Collection all have different size charts — and applying the wrong one is a very easy mistake to make when browsing online.

Ralph Lauren Women's Size Conversion Table

The table below applies to Lauren Ralph Lauren mainline womenswear — the most widely shopped women's line. Ralph Lauren uses US sizing, which maps to UK sizes as follows. Remember, Lauren runs generous, so many shoppers go one size down from their usual UK equivalent.

US SizeUK Size (equiv.)EU Size (equiv.)Bust (inches)Waist (inches)Hip (inches)XS / 0–263432–3324–2535–36S / 4–68–1036–3834–3626–2837–39M / 8–10124037–3929–3140–42L / 12–1414–1642–4440–4232–3443–45XL / 16–18184643–4535–3746–48

For Polo Ralph Lauren womenswear, these conversions hold but the fit runs slimmer — true to size or one down. For Ralph Lauren Collection, always measure your bust and shoulders specifically, as tailored pieces can run a full size smaller than the chart suggests.

Garment by Garment: What to Actually Expect

Even within a single line, Ralph Lauren garments behave differently depending on fabric and cut. Here's the honest breakdown:

Polo shirts (Polo RL) — Classic Fit runs quite generously; Custom Slim Fit is trim and close to the body; Slim Fit sits in between. If you want the relaxed, preppy-tucked look, Classic is your friend. If you want something more fitted and contemporary, go Custom Slim. Don't assume all polo shirts size the same — they genuinely don't.
Oxford & dress shirts — True to size overall, but the slim-fit versions run narrow through the shoulders and chest. If you have broader shoulders or a larger bust, size up in any fitted shirt style. The fabric on classic Oxfords has very little stretch, so there's no forgiveness if the shoulder seam isn't sitting right.
Knitwear & jumpers — This is where Lauren runs most generously. Their cashmere and merino pieces are beautiful, but they're cut with a relaxed American ease that can feel oversized if you're used to more fitted European knitwear. Sizing down by one in knitwear is very common, especially in the Lauren mainline. In Polo knitwear, true to size tends to work well.
Dresses (Lauren line) — The brand specifically notes that Lauren is cut for comfort and that sizing down may be appropriate, particularly in jersey and occasion dresses. I'd always recommend checking the waist measurement carefully — the Lauren line can be generous through the body but more fitted through the waist on structured styles, which catches people out.
Tailored blazers & Collection pieces — These are the most sizing-critical pieces in the entire Ralph Lauren stable. Collection blazers and structured jackets run slim through the shoulder and chest, and the quality of the construction means there is no ease built in beyond what's intentional. Get your shoulder width measured and cross-reference it with the product measurements before ordering anything at this level.
Trousers & chinos — Polo chinos are generally true to size, sitting at a natural waist with a classic leg. Their jeans are sized by waist measurement, which is more reliable than the label sizing. Always double-check the rise length — some styles can feel long through the leg for shorter frames.
Outerwear & coats — True to size across both Lauren and Polo lines. The Lauren line's guidance specifically notes to choose your true size for outerwear, even though you might size down in the ready-to-wear. Leave room to layer a thicker knit underneath if you're buying for winter.

My Honest Stylist Verdict on Ralph Lauren

Ralph Lauren is one of those brands that rewards knowing it well. Once you've worked out which line fits your body and your lifestyle, it becomes genuinely one of the most reliable wardrobes you can build — classic, beautifully made, and with a consistent design identity that means pieces bought five years apart still look intentional together. The polo shirts are iconic for a reason. The knitwear is some of the best at the price point. And a well-fitted Lauren blazer or Polo Oxford shirt has a relaxed authority that's almost impossible to replicate at lower price points.

The frustration is entirely in the shopping experience before you get to that point — the multiple sub-labels, the different fit philosophies, the US sizing. But once you've cracked your personal Ralph Lauren code, it's genuinely one of the most satisfying brands to wear.

Similar Brands Worth Knowing

If you love the Ralph Lauren world — that classic, considered, American-heritage aesthetic — here's where else I'd point you, across every budget:

High street picks for the classic, heritage-minded shopper:

Gant — The most natural Ralph Lauren neighbour on the high street. Same Ivy League, East Coast heritage energy, same love of Oxford shirts and cotton knitwear, and sizing that is broadly consistent and true to UK standard. If you're between RL purchases, Gant fills the gap beautifully.
Boden — Brilliantly underestimated for the classic, colour-rich end of the Ralph Lauren aesthetic. Their cotton shirts, striped knitwear, and tailored trousers are excellent quality for the price, and their sizing is among the most honest and detailed on the British high street.
Barbour — For the outdoor, country-house end of the RL wardrobe. Their waxed jackets and quilted gilets are the British answer to the RL equestrian look, and their sizing is reliable and well-documented. A permanent fixture for any wardrobe in this space.
Banana Republic — The American answer to RL's classic preppy tailoring, at a more accessible price. Their workwear and smart-casual separates are particularly well regarded, and sizing is consistent and uses US sizing (same as RL) so your reference point transfers directly.
Crew — J.Crew is the definitive American equivalent. Bright knitwear, Oxford shirts, tailored trousers, and the same relaxed-but-considered approach to dressing. Their sizing runs close to true US standard, and their quality at the price is excellent.
The White Company — For the quieter, pared-back end of the RL classic wardrobe. Exceptional quality basics, beautiful linen and cotton pieces, and sizing that is clear, detailed, and consistent. Their knitwear in particular is outstanding.
Hobbs — For the polished, occasion-ready end of the classic dressing spectrum. Their tailoring is precise, their sizing is predictable, and their aesthetic shares RL's love of heritage-influenced, structured dressing. A very reliable alternative for workwear and smart occasions.

Premium picks:

Tommy Hilfiger — The direct American heritage competitor. Shares RL's DNA almost entirely — nautical stripes, classic shirts, clean tailoring — but often at a slightly lower price point. Their sizing is clear and their womenswear is consistently well-reviewed.
Massimo Dutti — For a more European take on the same classic, quality-driven aesthetic. Their tailoring is impeccable and their sizing is detailed and accurate. Particularly strong on shirts, trousers, and structured knitwear.

Luxury alternatives:

Max Mara — The European luxury equivalent for the Ralph Lauren woman who wants impeccable tailoring and a wardrobe built to last decades. Their camel coats are iconic for exactly the same reasons as RL's classic pieces. Runs on the smaller side — check measurements carefully.
Loro Piana — For the quiet-luxury, quality-first end of the Ralph Lauren Collection customer. Exceptional fabrics, understated design, and a similar philosophy of investing in fewer, better pieces. Sizing is European and runs precise.

Two independent picks you won't find everywhere:

Sunspel — A British independent with over 160 years of heritage and a reputation for the finest quality cotton basics on the market. Their polo shirts, T-shirts, and lightweight knitwear are the discerning alternative to Polo RL — quieter, more understated, and with an exceptional quality of fabric that you notice immediately. Sizing is clear, true to UK standard, and detailed on their site.
Rowing Blazers — An American independent label that has built a devoted cult following by doing exactly what RL does, but with more irreverence and wit. Regimental blazers, fun rugby shirts, classic knitwear — it's heritage dressing with a sense of humour. Their sizing is US-standard and detailed per garment. If you love the RL preppy aesthetic but want something with a bit more personality, this is the brand to know.

Ralph Lauren Has Three Different Size Logics — Tellar Handles All of Them

Lauren, Polo, Collection — each sub-label sizes differently, all use US sizing, and none of them map cleanly to UK standard without knowing your measurements. Tellar takes the guesswork out completely, matching your actual measurements to your size across 1,500+ brands, including every Ralph Lauren line, in seconds. Free, always.

📏 Enter your bust, waist and hip — or a brand size you already trust
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