Biren Size Guide: Finding Your Perfect Fit
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Biren's t-shirts run unisex and true to size across both fits — Regular and Oversized — from XS to 3XL. The fastest way to find your size is to measure a tee you already own and compare it against the chest width and body length in the chart for the fit you're buying, since Regular and Oversized use different measurements even at the same labeled size.
How Do I Measure Myself for the Right Size?
Skip the tape measure on your body — measuring a shirt you already own and like the fit of is more accurate, since it accounts for how you actually like a tee to sit.
Lay the shirt flat and measure:
- Body length — from the top of the shoulder seam straight down to the bottom hem
- Chest width — flat across the chest, about one inch below the armhole
- Sleeve length — from the shoulder seam to the edge of the sleeve
Compare those three numbers against the size chart for the fit you're ordering. If you're between two sizes, sizing up gives a slightly more relaxed result on the Regular fit.
Regular Fit Size Chart (Inches)
| Size | Body Length | Chest Width | Sleeve Length |
|---|---|---|---|
| XS | 27.0" | 16.5" | 8.6" |
| S | 28.0" | 18.0" | 8.9" |
| M | 29.0" | 20.0" | 9.2" |
| L | 30.0" | 22.0" | 9.5" |
| XL | 31.0" | 24.0" | 9.7" |
| 2XL | 32.0" | 26.0" | 10.0" |
| 3XL | 33.0" | 28.0" | 10.4" |
Regular fit sizing runs true, with roughly ±1.5" of natural variance between individual pieces.
Oversized Fit Size Chart (Inches)
| Size | Width | Length |
|---|---|---|
| XS | 18.75" | 26.25" |
| S | 19.75" | 27.25" |
| M | 20.75" | 27.75" |
| L | 22.75" | 28.75" |
| XL | 24.75" | 29.75" |
| 2XL | 26.75" | 30.25" |
| 3XL | 28.75" | 31.25" |
The Oversized fit is cut wider and boxier than the Regular fit, with a shorter, dropped-shoulder silhouette. Sizing runs true to the oversized cut, with roughly ±1" of natural variance between individual pieces.
Should I Size Up, Down, or True to Size?
For most people, ordering true to size works best for both fits — the two size charts already reflect the intended fit of each cut, so sizing up on the Oversized chart usually adds more looseness than the silhouette is designed for.
The one exception is Regular fit if you're between two sizes: sizing up there gives a slightly more relaxed result without changing the overall pattern the way it would on the Oversized cut.
What's the Difference Between the Two Size Charts?
The Regular chart measures three points — body length, chest width, and sleeve length — because the fit follows your natural shoulder line, where sleeve length affects how the shirt sits. The Oversized chart measures width and length only, since the dropped-shoulder cut doesn't follow your natural shoulder point the same way, making sleeve length less relevant to how the fit reads.
Frequently Asked Questions
Are Biren t-shirts unisex?
Yes. Every Biren tee — Regular and Oversized — is built as a single unisex fit rather than separate men's and women's cuts, sized from XS to 3XL.
What if I'm between two sizes?
On the Regular fit, size up for a slightly more relaxed result. On the Oversized fit, order your true size — the cut is already built with extra room, so sizing up tends to add more looseness than intended.
Do Regular and Oversized use the same size chart?
No. The two fits use different measurements at the same labeled size — an Oversized Medium, for example, measures wider and differently than a Regular Medium. Always check the chart for the specific fit you're ordering.
How much size variance is normal between individual shirts?
Regular fit runs with roughly ±1.5" of natural variance between individual pieces, and Oversized fit with roughly ±1". This is standard for garment production and isn't a sign of a sizing error.
What's the best way to measure myself without a tape measure?
Lay a tee you already own and like the fit of flat on a table, then measure its body length, chest width, and sleeve length directly. Comparing those numbers to the chart is more reliable than measuring your body, since it reflects how you actually like a shirt to sit.
Check the full interactive charts on our Regular Size Guide and Oversized Size Guide pages, or browse the T-Shirt Collection to shop both fits.