Size charts your way
Build from templates or a CSV. Per product, collection, tag, or store-wide — in a fast, responsive storefront modal.
Size Chart & Fit Finder for Shopify
Fewer wrong-size returns — and the dollars you saved, in plain sight.
Shoppers find their size in two taps — no tape measure — and never enter it again: pick the size they usually wear and how they like it to fit, and every product on your store shows their size instantly. Then watch SizeFit estimate the returns you avoided.
Coming soon to the Shopify App Store See how it works
Launching soon · Free plan + Pro at $14/mo with a 14-day free trial.
Free plan, no shopper lockouts No customer data stored Your data, exportable in one click
The one promise
Wrong-size purchases are the #1 controllable return reason in fashion.
Every wrong-size return burns margin twice — the reverse shipping and the lost sale. SizeFit attacks that single problem: help shoppers pick the right size the first time, then prove it paid for itself.
How it works
Live in minutes, no developer needed
1
Create a chart
Start from a template (tops, bottoms, shoes, rings, generic) or import a CSV. Switch cm/inch automatically.
2
Assign it
Apply a chart store-wide, by collection, by product, or by tag. New products in a collection pick it up automatically.
3
Turn on Fit Finder
One click generates a starter size rule from your chart. “Find my size” becomes the primary button on your product page — preview the exact shopper experience live, fine-tune, save.
4
See the dollars saved
The returns-avoided dashboard estimates the returns and dollars you saved — with every assumption shown.
What you get
Everything to size right and prove it
Two-tap Fit Finder
Shoppers pick the size they usually wear and how they like it to fit — or enter a couple of measurements — and get a confident size. When they're between two, it tells them which way to round and how it will feel, from rules you set and can explain. Not AI.
Returns-avoided analytics
Turn matched recommendations into an estimated number of returns avoided and dollars saved — clearly labelled an estimate, assumptions shown.
One-click data export
Export every chart and rule to CSV or JSON whenever you want — on every plan, including Free. No lock-in, ever.
Speaks your shopper's language — automatically
The size chart, Fit Finder, and recommendation display in 6 languages — English, Spanish, French, German, Italian, and Portuguese — matched to your storefront's active language with no setup. (The labels you type into your own charts stay exactly as you wrote them.)
Privacy-first & fast
Anonymous fit sessions — no customer names, emails, or PII stored. The widget loads asynchronously and never blocks your product page.
Lead with the result
Most sizing apps give you a widget. SizeFit shows you the business result.
The returns-avoided dashboard multiplies matched fit recommendations by your own AOV and baseline return rate to estimate the returns and dollars you saved — so you can see whether it's working. Always an honest estimate, never a guaranteed refund figure.
Estimated
$2,140 saved
≈ 71 wrong-size returns avoided this month
Illustrative example. Real numbers come from your store's matched recommendations, AOV, and baseline return rate — with every assumption shown inline.
Pricing
One flat price. No per-shopper fees.
Unlimited fit recommendations on a flat $14/mo — your bill is the same whether the Fit Finder runs ten times or ten thousand.
Free
$0/ forever
Everything you need to start showing size charts.
- Up to 3 size charts
- Core chart templates + CSV import
- Automatic cm / inch switching
- 6-language storefront widget
- One-click data export (CSV / JSON)
- SizeFit watermark on the widget
Coming soon
Most popular
Pro
$14/ month
14-day free trial. Flat price — no volume or per-shopper fees.
- Everything in Free
- Unlimited size charts
- Fit Finder — unlimited recommendations
- Returns-avoided analytics dashboard
- No watermark
- Founder-run support
Coming soon
Free is always active — a billing gap never hides your existing size charts from shoppers.
Why merchants pick SizeFit
Honest pricing. Your data. A result you can see.
Two taps, then remembered everywhere
Shoppers pick the size they usually wear and how they like it to fit — no tape measure — and get a confident size. Enter it once and every other product on your store shows their size instantly, kept anonymously in their own browser.
Flat $14/mo, no usage fees
No per-shopper fees, no metered "credits", no order-volume charges. Apps that cap recommendations or scale price with your order volume cost more exactly as you grow — SizeFit doesn't.
Your data, exportable forever
Every chart and rule exports to CSV or JSON in one click — on every plan, including Free. No lock-in and no holding your charts hostage.
Recommendations you can explain
Every size suggestion comes from rules you set and can see. No black-box guessing — you always know why a shopper was shown a size.
Privacy by design
The Fit Finder takes anonymous measurements for a single session. SizeFit stores no customer names, emails, or identifiable data.
SizeFit vs. most sizing apps
Same job, done the way that's easier — and honest about the result.
Clear size charts and a fit finder, but easier for both sides of the counter, with no caps and a result you can actually see.
| Feature | SizeFit | Most sizing apps |
|---|---|---|
| Fit finder usage | Unlimited — flat $14/mo | Capped per month, or metered per recommendation |
| Price as you grow | Same flat price at any volume | Often rises with your order volume |
| Find your size | Two taps, then remembered on every product — no tape measure | Re-enter on each product, or a capped quiz |
| Your data | Free CSV/JSON export on every plan, including Free | Export paywalled — or refused |
| Proof it works | Honest, labelled returns-avoided ($) dashboard | Usage stats, not the business result |
| How it decides | Rules you set and can explain — no black box | “AI” you can't audit |
Built in the open
A new app, built carefully — and run by a founder who answers.
SizeFit by Instafluff is brand new, so we won't show you fabricated review counts or invented metrics. What we will promise: a tool that does one job well, honest "estimated" numbers with the assumptions in plain sight, and founder-run support — email us and a real human (often the founder) replies and works the problem until it's solved.
Cut wrong-size returns. Start free.
Add a clear size chart and a confident fit recommendation to your product pages — and see the dollars you saved.
Coming soon to the Shopify App Store Read the FAQ