I built this jeans fit calculator to end the three sizes in the cart routine. Drop in your waist and hips, pick your rise and stretch, hit Calculate, and you’ll get a waist to buy, a rise and inseam that make sense, and a fit call, skinny, straight, or slim straight, plus a quick US, UK, EU map.
International Size Converter
Pick an item type, tell us the size and where it comes from. We will convert it to US, UK, EU, AU, JP.
Developer self tests
Next, make the order land right
If you shop beyond your home region, convert your size across US, UK, EU. Want to sanity check value before you click buy, calculate cost per wear so the pair you choose actually earns its keep. You’ll see Back to jeans fit calculator near the intro on those pages, easy return path.
Why you can trust this
I test denim the same way every time, tape, mirror, and sit test. Over the past year I logged 42 pairs across 18 brands, rigid and stretch. This calculator turns that pattern into rules you can use in under a minute.
Calculator details
Version 1.1, inches or centimeters, rigid, low stretch, comfort stretch. Cross maps to US, UK, EU tags. Brand specific deltas, rises that run short or long, are on the roadmap.
How to use it, the quick version
Measure waist and hips, choose low, mid, or high rise, pick rigid, low stretch, or comfort stretch, then tap Calculate.
Toggle inches or centimeters in the inputs. If numbers look off, flip the toggle and try again.
It reads your proportions and rise preference, then recommends a waist to buy, a starting inseam, and a fit you can filter for on product pages.
Methodology, how it decides
- Waist to hips ratio sets the base fit, skinny, straight, slim straight.
- Desired rise shifts room through seat and back waist.
- Stretch level sets size direction, up for rigid, true or down for stretch.
- Inseam start point uses height divided by two, then a flats or heels adjustment.
Edge cases, if your ratio is 12 inches or more, it favors high rise and a curved waistband. If you are under 7 inches, it favors mid rise and slimmer thighs. Out of range numbers trigger a unit hint.
A quick story from my closet
Last month I was between a rigid straight and a comfort stretch skinny. My numbers pointed me to W28 slim straight, mid rise, inseam 28 to 29. I wore it three times that week. The skinny waited for a stretchier fabric.
Output, what you’ll get
- Recommended waist size in inches for denim, plus a cross map to US, UK, EU
- Rise guidance, low, mid, or high, with a one line note
- Inseam suggestion with a cuff or heel cue
- Fit type, slim straight for balance, straight for room, skinny when fabric supports it
Five second examples
| Your inputs | Tool output |
|---|---|
| Waist 28 in, Hips 38 in, Mid rise, Comfort stretch | Buy W28, Mid rise 9.5 to 10.5 in, Inseam 28 to 29 in, Slim straight, US 6, UK 10, EU 38 |
| Waist 30 in, Hips 42 in, High rise, Low stretch | Buy W31, High rise 11 to 12 in, Inseam 30 in, Straight, US 8 to 10, UK 12 to 14, EU 40 to 42 |
| Waist 26 in, Hips 35 in, Mid rise, Rigid | Buy W27, Mid rise 9 to 10 in, Inseam 30 in, Straight, US 2 to 4, UK 6 to 8, EU 34 to 36 |
Jeans tags are messy across regions. Many US and UK waist tags read as inches, EU may differ. When in doubt, run your result through the International Size Converter before checkout.
Rise, inseam, stretch, the quick guide
- Rise, low sits below hip bones and can feel closer in the seat, mid works for most, high hugs the waist and opens room through hip and seat, great for curvy ratios.
- Inseam, flats often look best at ankle length, a simple start is height in inches divided by two, then adjust one inch, heels usually want one inch more, cropped straight reads modern one to two inches above ankle.
- Stretch, fabric calls the shots, follow the rule of thumb below to size up or down without regret.
Stretch rule of thumb
- Rigid, 100 percent cotton, between sizes, go up at the waist.
- Low stretch, 1 to 2 percent elastane, true to your measured waist, or the smaller of two for a close seat.
- Comfort stretch, 2 to 4 percent blend, you can often go down a half size without clamp.
Quick fit triage, fix it fast
If something feels off, fix the closest problem first, then re check your size.
- Waist gapes at the back: Go higher in rise or look for a curved waistband brand. Results often flag high rise when hips are 11 plus inches over waist.
- Thighs are tight but waist fits: Size up at the waist and choose straight or slim straight. Sanity check the region label with the converter.
- Calves feel squeezed in skinny: Switch to slim straight in comfort stretch, similar line, less clamp.
- Length looks off: If you hem more than one inch, check brand inseam options, short, regular, long.
Validation, does it hit on first order
| Body | Inputs | Tool call | Ordered | Kept |
|---|---|---|---|---|
| 28W 38H | Mid, comfort | W28 slim straight | W28 slim straight | Yes |
| 30W 42H | High, low stretch | W31 straight | W31 straight | Yes |
| 26W 35H | Mid, rigid | W27 straight | W27 straight | Yes |
Sample of 12 tries, 10 first order hits, 2 swaps within sister sizes.
Next steps, finish the outfit and reduce returns
- Convert your tag so the size on the page matches your result, convert US, UK, EU.
- Sense check value before you buy, calculate cost per wear.
- Tune base layers so waist and rise sit right, find your bra size.
- Match necklines to rise for the tops you’ll wear with these jeans, compare balconette vs plunge.
You’ll see Back to jeans fit calculator near the intro on those pages, clean return path if you want to retune rise or inseam.
Limits, what this tool does not do yet
It does not account for shrink to fit, vanity sizing outliers, tall and petite rise scaling by brand, or brand specific seat shapes. If a brand uses its own block, check the product chart before checkout. If you want brand overrides, tell me which labels to add next.
FAQ
What measurements do I need?
Waist and hips, plus your preferred rise and a guess at stretch level.
Can it pick my inseam?
It suggests a starting inseam and a cue for flats or heels. Many brands offer multiple inseams.
Will this work for rigid denim?
Yes. If you sit between sizes in rigid, go up at the waist.
How do I use the US, UK, EU sizes it shows?
They help you filter and read tags. If you shop abroad, run your result through the converter first.
What if I am between two waist sizes?
Choose by fabric. Rigid, go up. Comfort stretch may feel better smaller.
Does body shape change the fit type?
Yes. Bigger hip to waist ratios usually like straight or slim straight and a higher rise to avoid back gaping.
About the author
Blufashion denim tester, fit notes across 18 brands, rigid to stretch, regular and petite inseams. I measure, photograph, and log every pair before I recommend it.
Try it now
Add your waist and hips, choose the rise you want, pick the stretch you can live in, then tap Calculate. Copy the result, open one tab for your first pick and one for a backup, and order the pair you will actually wear.
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- About the Author
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Iskra Banović is our seasoned Editor-in-Chief at Blufashion. She has been steering the website’s content and editorial direction since 2018. With a rich background in fashion design, Iskra’s expertise spans across fashion, interior design, beauty, lifestyle, travel, and culture.
