T-Shirt Size Ratio Calculator
Split an apparel order across sizes without guessing, including the extended-size upcharges.
A client orders 250 shirts and says "just do a normal size run." Somebody has to turn that into a real size breakdown, and if the extended sizes are not priced separately, the upcharges come out of your margin.
Pick a curve, set the quantity, and get a size breakdown that adds up exactly, with the 2XL and up upcharges calculated as their own line. Adjust any percentage and the rest reconcile.
Split the size run
Pick a curve, set the quantity, adjust any percentage. The breakdown always adds up to your exact order.
Mixed adult audience, the ordinary starting point when nobody has collected sizes.
The order
Extended-size upcharges
Upcharges are per piece, on top of the base cost. Check the blank, they differ by brand and by style within the same brand.
Adjust the curve
Entered percentages total 100. They are normalized, so any total works.
Quote this when the client wants one price for every size
37 pcs at 2XL and up, $88.00 in upcharges
Size breakdown
| Size | Qty | Share | Upcharge | Line total |
|---|---|---|---|---|
| S | 25 | 10% | — | $162.50 |
| M | 50 | 20% | — | $325.00 |
| L | 75 | 30% | — | $487.50 |
| XL | 63 | 25.2% | — | $409.50 |
| 2XL | 25 | 10% | $2.00 | $212.50 |
| 3XL | 10 | 4% | $3.00 | $95.00 |
| 4XL | 2 | 0.8% | $4.00 | $21.00 |
The upcharge line is the one that disappears into a flat per-piece price. On a corporate run it is regularly one to two percent of the order value, paid entirely out of your margin unless you blend it in on purpose.
Percentages are normalized, so they do not have to total 100. Counts are distributed by largest remainder, which is why the sizes sum to your quantity exactly instead of coming up short at the printer.
How the math works
The curves
The presets are the ordinary starting points: a general adult run, a men-heavy run, a women-heavy run, a youth run, and a corporate office run that skews larger than event giveaways do. They are starting points, not truth. Your client list is the better data.
Reconciling to the exact total
Percentages rarely land on whole shirts. The calculator distributes by largest remainder, which means the breakdown always sums to your exact quantity instead of coming up two short at the printer.
Extended-size upcharges
Most blanks add cost at 2XL and again at 3XL and 4XL. Those upcharges get their own line here because they should get their own line in your quote too. A run with 18 percent extended sizes costs real money that a flat per-piece price silently eats.
Blended cost
The output shows the blended per-piece cost across the whole run, which is the number to quote from when a client wants one price for all sizes.
Questions, answered
A common general-population starting point is roughly 10 percent S, 20 percent M, 30 percent L, 25 percent XL, 10 percent 2XL, and 5 percent 3XL and up. Corporate and older audiences skew larger, event giveaways and youth-heavy audiences skew smaller. Treat it as a first draft you adjust with what you know about the group.
Other free tools
In-Hands Date Calculator
Give it the event date, get the last day the order can actually be placed.
Decoration Pricing Calculator
Screen print, embroidery, DTF, and laser priced the way suppliers actually bill it.
Promo Quote & Margin Calculator
Cost in, sell price out. Or a client budget in, and the margin it leaves you.
Kitting & Fulfillment Quote Widget
What a kitted box actually costs to assemble, before you quote it as "a few bucks each."
Merch Wit Generator
Merch copy that sounds like a person wrote it, for whatever niche you sell into.
Want this running inside your systems?
A calculator is the demo. The version I run reads the order, applies the rates, and produces the client document without anyone opening a spreadsheet. The teardown is free and I will tell you plainly whether it is worth automating.