A size recommender that says why
Shoppers enter their measurements and get one size, with the reason for each measurement and how sure it is. No account and nothing sent to us: it runs in their browser and remembers their size on every product. On every plan, the free one too.
Try it on a real chart
This is the size guide of the men’s T-shirts template. Open Find my size, enter a chest of 98 cm and a waist of 84 cm, then switch between snug, regular and loose.
One size, and the reason
Each measurement gets a line: “Chest 94 cm: M, middle of the range”. Shoppers see the size, how confident the answer is, and the next size when it is a real alternative.
Between two sizes
It says so, and which one to take, in the order of your sizes.
Never a wrong push
No size beyond your largest. A size out of stock is said as such, with the nearest one in stock.
Centimeters typed as inches
Spotted, with a button to switch units.
Snug, regular or loose
Shoppers pick the fit they like and the answer moves at once. Your chart’s fit scale, from runs small to roomy, is part of the answer, and so is the way it was measured.
Garment measurements
Charts measured on the garment, laid flat or around, are read with the ease published for each kind of garment.
Stretch and compression
A stretch or compressive fit changes the target, not your chart.
Set per chart
Body or garment, fit scale, fit preference on or off, with a live test in the editor.
Their size, on every product
Measurements stay on the shopper’s device and come back on every product page, “Your size: M”, without an account. Children’s measurements are kept apart from the parent’s.
Selects the variant
“Select this size” picks the matching option in your theme’s size selector.
Stays on the device
Nothing is sent to Ruban Size, nothing is stored on our side.
Height and weight, for shoppers with no tape Fit
Shoppers enter their height, weight and age. Ruban Size estimates their measurements with published body equations (ANSUR, Cheverud, Bozeman) and gives the chances of each size, like “M 55% · S 24% · L 19%”. Always shown as an estimate, never for under 18s.
Measured on 40,000 shoppers
We tested Find my size on 40,000 simulated shoppers whose measurements are drawn from published body surveys (NHANES 2015 to 2018, ANSUR II), against a plain lookup in the same charts.
- 65.8%got their exact size (a plain lookup: 49.2%)
- 94.5%got their size or the next one (a plain lookup: 72.1%)
- 64.5%exact on charts measured on the garment, where a lookup gets 9 to 14%
How it works
Use a chart with measurements
Chest, waist, foot length, head: any of your charts, or a template.
Find my size appears
In the size guide, as soon as the chart has measurements.
Tune it per chart
Fit scale, body or garment, fit preference, in the chart’s Fit tab.
Find my size: questions
Which charts get Find my size?
Every chart with measurements: 37 of the 39 templates have it. It recognizes 20 product categories, from tops and jeans to bras, shoes, rings and dogs, and the measurements that matter for each.
Do shoppers need an account?
No. Their measurements are kept in their browser, on their device, and never sent to us.
Is it a black box?
No. It reads your chart, applies published fit rules and says why for every measurement. The height and weight estimate on Fit uses published body equations and always says it is an estimate.
Is Find my size on the free plan?
Yes, on every plan. The estimate from height, weight and age is on Fit.
Try Ruban Size on your store.
Free for 5 size charts. Pro and Fit start with a 14-day free trial, billed by Shopify.