Why a 20% discount isn't a 20% cut
The intuition almost everyone starts with is that taking 20% off the price costs 20% of what you were making. It doesn't, and the gap between those two things is where sale seasons quietly go wrong.
Your costs don't move. The wax, the jar, the box, the hours at the bench, the postage — all identical whether the buyer paid full price or used a code. So the discount doesn't come out of the whole price. It comes out of the profit, which is the only part that can move.
On a $28 product with $16.21 of cost, $6.50 of shipping charged against $8.20 of real postage, and typical marketplace fees, full price leaves about $5.67. Take 20% off and it leaves about $0.72. The price fell by a fifth; the profit fell by nearly seven eighths.
The volume nobody calculates
Sales are usually justified by volume — you make less per item but sell more of them. That's sound in principle, and the question is simply how many more. Divide profit at full price by profit at the discount and you have it.
For the numbers above that's $5.67 ÷ $0.72, or roughly eight times the volume to end the month where you'd have ended it anyway. Not 20% more. Eight times. A sale that doesn't come close to that ratio didn't lose you money in an obvious way — it just replaced a quiet month with a busy one that paid the same.
The point where it turns
Past a certain discount the arithmetic stops being about volume at all, because there's no profit left to multiply. Every additional sale then costs you money, and selling more makes it worse.
That threshold is usually far lower than sellers expect, because fees and shipping shortfalls don't shrink when you discount. The calculator marks it, and on a typical handmade product with a healthy-looking margin it often lands somewhere in the low twenties of a percent.
Discounts that don't cost the same
If the goal is to move stock or reward repeat buyers, some levers are cheaper than a straight percentage off. Free shipping thresholds ("free postage over $45") lift order value instead of cutting margin. Bundles spread one shipping cost and one set of flat fees across several items. A small gift with purchase costs its materials rather than a share of every sale.
None of that means discounts are wrong — they're a legitimate tool. It just means running one at a number you picked because it sounded good is expensive, and checking first costs nothing.
Common questions
Should I just never run sales?
No. Sales clear slow stock, bring back past buyers and help a listing's ranking. The point isn't to avoid them — it's to choose the number deliberately and know what volume it needs to work.
A 10% code you can sustain beats a 30% one that costs you money on every order.
What about Etsy's own sale features?
Run them through this the same way. A percentage is a percentage regardless of who's offering it, and marketplace fees are charged on the discounted total — which does soften the blow slightly, since a lower price means a smaller fee. The calculator accounts for that.
Why is my safe discount so low?
Usually one of two things. Either the item was underpriced to begin with, so there was little margin to give away — the pricing calculator will show that. Or postage is losing money separately, which eats the room a discount would otherwise have.
Are my numbers stored anywhere?
No. Everything runs in your browser, there's no account, and nothing is uploaded.