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 proof of the dollars you saved.
Shoppers pick the size they usually wear and how they like it to fit. No tape measure. Every product on your store shows their size instantly, and SizeFit estimates the returns you avoided.
Free plan available. Pro is $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
Help shoppers pick the right size, then prove it paid for itself.
Wrong-size guesses are one of the biggest controllable return reasons in apparel. Every one burns margin twice, the reverse shipping and the lost sale. SizeFit attacks that single problem, then estimates the returns and dollars you saved.
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.
See it in action
A closer look at SizeFit
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 recommendations display in 6 languages, matched to your storefront's active language with no setup. English, Spanish, French, German, Italian, and Portuguese.
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
See the business result, not just a widget on the page.
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, illustrative example
$2,140 saved
About 71 wrong-size returns avoided this month
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
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
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.
Who builds it
Made by Instafluff.
SizeFit is built by Raphael Mun, Instafluff. Principal Software Engineer at Microsoft by day, indie app and game developer by night, shipping one focused, well-made tool at a time.
What you are signing up for
Free plan. Export anytime. No lock-in.
The Free plan is always on
Your size charts keep showing to shoppers even if a payment fails. We never hold your storefront hostage.
Your data leaves whenever you do
One click exports every chart and rule to CSV or JSON, on every plan including Free.
One flat price
Pro is $14 a month whether the Fit Finder runs ten times or ten thousand. No per-shopper fees, no surprise bills as you grow.
No customer data stored
The Fit Finder uses anonymous measurements for a single session. No names, no emails, nothing identifiable.
Every recommendation has a reason you can read
The size logic is rules you set, not a black box.
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.