You wear M in one brand.
What is their M?
Measure one garment that already fits you. Read any brand's size chart against it and see the difference in centimetres.
We never ask for your measurements. We compare a garment you already own against theirs.
- Body figures held
- 0
- Garments to measure
- 1
- Unit of the answer
- cm
The drift ruler
Your benchmark garment is pinned at zero. Their sizes sit where their real centimetres put them. Change the chart and watch the ladder move — no account needed.
Chart C lists body measurements. Chart D states neither its type nor its unit, so no recommendation is produced for it at all.
Your benchmark shirt measures 54.0 cm at the chest, laid flat. The scale above is drawn in true centimetres.
The figures describe the clothing laid flat. Directly comparable with your benchmark.
- Cut. A slim block and a relaxed block can share a chest measurement and sit completely differently.
- Fabric stretch. A knit gives where a woven does not, and no chart records that.
- Shrinkage after washing. Cotton moves after the first wash and the chart is measured before it.
| Size | Their measurement | Difference | Reading |
|---|---|---|---|
| XS | 48.0 cm | −6.0 cm | 6.0 cm narrower than your benchmark |
| S | 51.0 cm | −3.0 cm | 3.0 cm narrower than your benchmark |
| M | 54.5 cm | +0.5 cm | 0.5 cm wider than your benchmark |
| L | 58.0 cm | +4.0 cm | 4.0 cm wider than your benchmark |
| XL | 61.5 cm | +7.5 cm | 7.5 cm wider than your benchmark |
Three measurements, one screenshot,
and a number you can act on.
01Measure one garment you already own
Pick the shirt you keep reaching for. Lay it flat and measure across the chest, seam to seam at the shoulder, and down the back. Four figures, once. This is your benchmark.
Nothing about you is recorded. The tape only ever touches the clothing.
02Photograph their size chart
Screenshot the chart on the brand's product page, or photograph the printed one. We read the table structure, pull the figures, and work out two things before anything else: the unit, and whether the chart lists a body or a garment.
Photographs of people are not accepted at the upload step.
03Read the difference
Your benchmark sits at zero. Every size on their chart is placed at its true distance from it, in centimetres. You get a size, a signed difference, and — when you are caught between two — what each side costs you.
A difference in centimetres. Never a promise that it will fit.
A sheet of numbers and a card you can carry.
Both outputs are drawn from figures, not from photographs of anyone. The service holds no images of people, produces none, and would have nothing to draw them from.
One returned parcel costs more than a year of this.
The free plan carries one benchmark garment and five comparisons a month — enough to get through one shopping decision. Paying lifts the limit that actually bites: one benchmark only covers one category. A shirt's chest tells you nothing about a trouser waist.
Free
Enough to get through one shopping decision.
- 1 benchmark garment
- 5 chart comparisons per month
- Chart type and unit verdict always shown in full
- Decision card carries a watermark
Fit
Most chosenOne benchmark only covers one category. This lifts that.
- Unlimited benchmark garments
- Unlimited chart comparisons
- No watermark on comparison sheets or decision cards
- Brand history: what you bought last time, and in which size
- Export comparison sheets and decision cards
Rack
For a household measuring more than one wardrobe.
- Everything in Fit
- Multiple profiles in one account
- Category partitions: shirts, trousers, jackets, knitwear kept apart
- Priority processing queue
Credits are a service allowance, nothing else. They are not money, they hold no cash value, they cannot be redeemed, transferred or refunded, they do not carry over from one period to the next, and there are no top-up packs. Every plan renews automatically until you cancel, and cancelling takes the same number of clicks as subscribing did. Full plan detail
The things worth asking before you pay.
Anything not covered here, write to support@onewayparis.com. The full terms live in the CGV and the AI notice.
Do I have to measure myself?
No. Not once, not optionally, not at any point. There is no field on this site for a body measurement and no column for one in the database behind it. What you measure is a garment you already own, laid flat on a table. That is the whole method: a garment compared against a garment. A body measurement compared against a garment measurement has an unknown amount of ease sitting between them, which is precisely the gap that makes size labels unreliable in the first place.
What happens to my data, and is it used for training?
Your benchmark figures and the chart images you upload are used to answer your own comparisons and nothing else. They are not used to train any model, ours or anyone else's. Delete your account and they are deleted with it. We do not accept photographs of people or of bodies at the upload step, so no such image is ever held.
How accurate is this, and what is the service actually claiming?
The service reports a difference in centimetres between two measured garments. That arithmetic is exact and runs in your browser. What it is not is a prediction about how something will feel on. Cut, fabric stretch and shrinkage after washing all change the outcome and none of them appear on a size chart. Read the difference as information, not as a verdict.
What if I follow the difference and it still does not fit?
That can happen, and the service says so before you buy rather than after. What you get is a signed difference against a garment you already own — never an assurance of fit. Two garments can share a chest measurement to the millimetre and hang completely differently because the block underneath them is different. When you are caught between two sizes, we tell you what each side costs you and leave the choice where it belongs.
Why does the recommendation sometimes not appear at all?
Because we could not determine whether the chart lists body measurements or garment measurements, or could not determine whether the figures are centimetres or inches. Comparing the wrong type is the main cause of sizing errors, so in that case we show the verdict and stop. We would rather give you nothing than give you a confident number built on the wrong premise.
How do cancellation and the right of withdrawal work?
You may cancel a subscription at any time from your billing page; the cancellation link sits in the same place and takes the same effort as subscribing did. Access continues until the end of the period already paid for. Under French consumer law you also hold a fourteen-day right of withdrawal on digital services, which lapses early only if you expressly asked for immediate performance and expressly acknowledged losing it — two separate boxes at checkout, neither of them pre-ticked.
Do credits roll over, and can I buy more?
No, and no. Credits are an allowance attached to a period. Unused credits expire at the end of that period, there is no top-up pack, and no stored balance exists on this site. If you consistently run out, the answer is a higher plan, not a purchase of credits.
Is there an age restriction?
The service is offered to adults. If you are a minor you may use it only with the agreement of a parent or legal guardian, who accepts the terms on your behalf. We do not knowingly hold an account for a child under fifteen.
Measure once. Read every chart after that.
One benchmark garment, five comparisons a month, no card. Enough to get through the next thing you were going to gamble on.