How to Date Vintage Clothing by Labels

If you want to know how to date vintage clothing, the labels sewn inside it are the closest thing to a paper trail the garment carries. Union tags, registration numbers, care instructions, country of origin, and even the size format each changed in documented ways, and each change draws a line you can date against.

To date vintage clothing, read the tags sewn inside the garment: a union label such as the ILGWU tag brackets an era by its design and wording, an RN number gives an earliest-possible date, and sewn-in care instructions place a piece in the early 1970s or later. Start by finding every tag, then check each against documented label changes.

By the end of this guide you will be able to read a union label for its era, use RN numbers as an earliest-possible date, apply the early-1970s care-label dividing line, and back it all up with hardware and sizing clues so no single tag can mislead you.

Quick identification checklist

Find every tag in the garment: brand, union, fiber content, care, size, and lot all date independently.
Read any ILGWU union label closely; its design and wording narrow the era.
Treat detailed sewn-in care instructions as a sign of the early 1970s or later.
Check the zipper: metal suggests older, nylon coil spread from the late 1960s onward.
Use RN or WPL numbers as an earliest-possible date, never as the garment’s date.
Note sizing quirks; half sizes, odd junior sizes, and missing size tags are clues in themselves.

How to date vintage clothing with union labels

The classic American dating tool is the union label, especially the ILGWU tag of the International Ladies’ Garment Workers’ Union, which appears in huge numbers of US-made women’s garments from the early twentieth century into the 1980s. The label’s design changed over the decades, and the changes are well documented in collector references.

The most useful wording clue is the union federation name. Labels that mention the AFL belong to the era before the federations merged in the mid-1950s, while labels reading AFL-CIO came after. Later still, the familiar red, white, and blue ILGWU label with “union made” styling belongs broadly to the mid-1970s and 1980s. Union labels then fade out as production moved offshore, so their presence at all points to an American-made garment from before the 1990s. You do not need to memorize every variant; matching your label’s colors, shape, and wording to a dated example in a reference collection usually brackets the garment within a decade.

RN and WPL numbers: earliest-possible dates

Many American labels carry an RN number, a registration number identifying the company behind the garment. These numbers are issued sequentially, so lower numbers belong to companies registered earlier, and the modern series dates from the late 1950s. WPL numbers come from the older wool-products labeling system that began around 1940 and stopped being issued when the RN series took over, so a WPL number signals a company registered in that earlier window.

The critical caveat: these numbers date the company’s registration, not your garment. A maker registered in the 1960s could still be sewing the same label in the 1990s. Treat the number as an earliest-possible date, then look up the company to learn when it operated. That range, combined with the label’s typography and the garment’s construction, usually narrows things considerably.

The care-label line: a clean before-and-after

US regulators began requiring permanently attached care instructions in garments in the early 1970s, and that rule creates the cleanest dividing line in label dating. A garment with a sewn-in tag spelling out washing or dry-cleaning instructions is almost always from the early 1970s or later. A factory-made garment with no care instructions anywhere is usually earlier, though check the seams for a stub where a tag was cut out, and remember that home-sewn clothing never had one.

Fiber-content rules arrived earlier, around 1960, so a tag listing generic fiber percentages such as “100% polyester” already suggests that era or later, while older labels tend to use trade names and fabric descriptions instead.

Zippers and other hardware clues

Hardware backs up what the labels say. Metal zippers were standard through the 1960s; nylon coil zippers spread in the late 1960s and dominated by the mid-1970s, so a coil zipper in an otherwise old-looking dress argues for a later date or a repair. Placement matters too: side-seam zippers are typical of dresses from the 1940s and 1950s, while center-back zippers became the norm from the late 1950s onward. Snaps, hooks, and metal buttons with shank backs lean earlier; fused interfacing and serged (overlocked) seam finishes lean later.

Always ask whether the hardware looks original. A bright new zipper set into faded fabric is a repair, and it dates the repair, not the dress.

Country of origin, lot tags, and sizing quirks

Where a garment was made shifted in datable waves. Union-labeled “Made in U.S.A.” dominates mid-century. “Made in Japan” appears on postwar imports, followed by Hong Kong, Taiwan, and Korea through the 1960s to 1980s, with “Made in China” becoming common only from the late 1980s onward. A label reading “British Crown Colony of Hong Kong” predates the 1997 handover and usually signals the 1960s through 1980s. Separate small tags carrying lot or style numbers are an older manufacturing convention worth noting too.

Sizing is its own clue. Vintage sizes run small against modern ones because size standards have inflated over the decades, so never date or buy by the printed number. Half sizes such as 16½, designed mid-century for shorter figures, point to that era. Odd-number junior sizes, “sub-teen” ranges, and garments with no size tag at all, common on older and custom-made pieces, each lean earlier. Measure the garment flat and let the numbers be evidence rather than instructions.

The larger lesson runs through all of these sections: no single tag dates a garment. Labels get swapped, deadstock sits unsold for years, and repairs add new parts to old clothes. Confidence comes from stacking clues, with a union label era, an RN range, a care-label answer, and the hardware all pointing at the same decade.

Watch-outs and common mistakes

Labels can be cut out, swapped, or added; check that stitching matches the garment’s other seams.
Modern “vintage-style” brands imitate old label art; weigh construction and fabric alongside the tag.
Do not date by RN number alone, since companies keep the same number for decades.
A missing union label does not mean post-1990s; plenty of earlier garments came from non-union shops.
A replaced zipper or new buttons date the repair, not the garment.

Photo tips that improve identification

Shoot every tag straight-on, flat, and in focus, including the back of tags where extra numbers hide.
Photograph the zipper pull and teeth close up so metal versus coil is obvious.
Capture interior seams and finishes, since pinked, bound, or serged edges all carry date information.
Take a full flat-lay of the garment so silhouette and proportions support the label evidence.

Common questions

How do you look up an RN number on vintage clothing?

An RN number identifies the company that made or marketed the garment, and the numbers were issued sequentially, so lower numbers belong to earlier registrations. Searching the number in a registration database tells you when the company registered and often when it operated. Remember the result is an earliest-possible date for the garment, not its actual date, because companies keep the same number for decades.

What does an ILGWU label tell you about a garment’s age?

The ILGWU label appears in US-made women’s garments from the early twentieth century into the 1980s, and its design changed in documented stages. Labels mentioning the AFL predate the federation merger of the mid-1950s, while AFL-CIO wording came after, and the familiar red, white, and blue version belongs broadly to the mid-1970s and 1980s. Matching your label’s colors, shape, and wording to a dated reference example usually brackets the garment within a decade.

Is clothing without a care label always pre-1970s?

Usually, but not always. US regulators began requiring permanently attached care instructions in the early 1970s, so a factory-made garment with no care tag anywhere leans earlier. Check the seams for a stub where a tag was cut out, and remember that home-sewn clothing never had a care label in any era, so confirm the date with the zipper, sizing, and other label clues.

When to use the Antique Identifier app

Photograph the full garment on a hanger or flat, then take tight shots of every label, the zipper, and any distinctive buttons or hardware. The app can quickly narrow the likely era and style category, which tells you which label references to check first. If it suggests a rare designer piece or an unusually early date, treat that as a prompt to verify against documented label examples rather than a final answer.

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