Percentages into whole pieces
A size curve arrives as percentages and an order has to be whole garments. Rounding each size independently is how you end up a piece or two above or below the total you meant, which either breaks a case quantity or quietly changes what you are paying. The largest remainder method avoids that: take the floor of every size, count how many pieces are still unassigned, and hand them out to the sizes with the biggest fractional parts. The rows then sum to the total by construction, every time.
The percentages do not have to add to 100. They are normalised against whatever they add to, so you can type the raw counts from a sign-up sheet, an old invoice or a team roster straight into the fields and get the same answer.
The identity worth knowing
When the order total is fixed, the number of pieces left over always equals the number of orders you could not fill. This is not a coincidence and it is not an approximation — the pieces have to come from somewhere, so every one you put into a size that did not sell is one missing from a size that would have. It is the reason a curve error is not a rounding problem. The same wrong guess bills you twice, once as stock in a box and once as revenue that never happened.
Upcharges
The larger sizes usually cost more, and the calculator takes those as separate figures on top of the base rather than folding them into an average. Averaging is what makes a curve heavy in extended sizes look cheaper than it is, and it hides the fact that guessing those sizes low is the mistake with the fewest substitutes — somebody who wants a 3XL will not take an XL, while the reverse trade happens all the time.
Related
Cost each piece before it reaches this page with the setup and break-even calculator for a printed job or the embroidery run time calculator for a stitched one. For the reordering rhythm of stock you hold continuously rather than a one-off order, see the inventory order calculator. Body measurements and finished garment sizes are a different question — the clothing size converter and the blanket and garment size calculator cover those.
Questions people ask
Where do I get a demand curve if this is a first order?
From whatever list you already have. A sign-up sheet with sizes on it is the best source and it costs nothing to circulate before you order. Failing that, a previous order from the same group, or the sizes that sold through last time. If you genuinely have nothing, leave the demand row empty and the calculator will just give you the split without the comparison rather than pretending to know.
Why do the percentages not have to add to 100?
Because normalising is free and typing raw counts is easier than converting them. Twenty three people asking for L and eleven asking for M can go in as 23 and 11, and the curve comes out the same as if you had worked out the percentages first. It also means you can adjust one size without having to rebalance the other five.
What if I want to order extra rather than exactly the total?
Put the padded number in the total. The calculator splits whatever total you give it, so ordering 130 against 120 of demand shows you the extra spread across the curve and the leftovers it produces. That is a legitimate strategy when running short is worse than holding stock, and seeing the cost of the padding next to the cost of the shortfall is the point.
Does the leftover figure assume I never sell them?
Within this order, yes. It costs them at what you paid, which is the money currently sitting in a box. If you expect to sell some later at a discount, the real cost is somewhere between that figure and zero, and the calculator does not guess where. It gives you the upper bound, which is the honest number to plan against.
Should the upcharge be what my supplier charges or what I charge?
What you pay. The selling price field is separate and applies to every size at the same figure, which is how a lot of shops sell — one price for the shirt, upcharges absorbed. If you charge extra for the big sizes too, this page will understate your revenue on those rows; run the extended sizes separately if that difference matters to the decision.