Free calculator
Is Black Friday worth it for your online shop?
Put in the numbers for one product. You'll see what you actually keep at your Black Friday price, and how many you'd need to sell just to make the same profit as one sale at full price.
Your numbers
Your normal full price, e.g. a rain jacket at €100.
Check your last invoice for this product. Don't know it? Try 60% of the price.
Add your other costs (optional)
Leave at 0 if the customer pays for delivery.
Check your Shopify Payments or card provider rate.
What you spend on ads and promotion, divided by the sales it brings in. Only counts on discounted sales.
What you keep
Each Black Friday sale makes you €20 instead of €40.
In 2025, more than three in four UK independent retailers sat out Black Friday, up from 69% the year before. Many said their margins were already too thin to cut. (British Independent Retailers Association)
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How to use it
Pick one product you'd put in a Black Friday sale. Put in what you sell it for, what you paid your supplier, and the discount you're thinking of. That's it. If you want the full picture, open "Add your other costs" and put in delivery, card fees and what you'd spend on ads.
Why a small discount takes a big bite
Say you sell a rain jacket for €100 and you paid the supplier €60. You keep €40.
Take 20% off and you sell it for €80. It still cost you €60, so now you keep €20. You've knocked a fifth off the price and lost half your profit. You'd have to sell two jackets to make what one used to make.
Your profit on one €100 jacket
| You paid the supplier | Sold at €100 | Sold at €80 (20% off) | Sold at €70 (30% off) |
|---|---|---|---|
| €70 | €30 profit | €10 profit | €0 profit |
| €60 | €40 profit | €20 profit | €10 profit |
| €50 | €50 profit | €30 profit | €20 profit |
| €40 | €60 profit | €40 profit | €30 profit |
How many jackets you need to sell to make the same profit as one at €100
| You paid the supplier | Sold at €80 (20% off) | Sold at €70 (30% off) |
|---|---|---|
| €70 | 3 jackets | Impossible |
| €60 | 2 jackets | 4 jackets |
| €50 | Nearly 2 | 2 and a half |
| €40 | 1 and a half | 2 jackets |
And every one of those discounted jackets still has to cover delivery, card fees and the ads you ran to promote the sale.
Margin is not markup
If you add 40% on top of what you paid, your margin isn't 40%. A jacket that cost you €60 and sells for €84 has a margin of about 29%. That's the number that matters here, and the calculator works it out for you from the two prices.
What the result means
If the calculator says you need to sell three for every one, ask yourself honestly whether Black Friday will triple your sales of that product. A lot of the extra orders come from people who'd have bought anyway, just later and at full price.
One study of Black Friday in German retail found demand drops for about three weeks beforehand as shoppers hold off, and across the whole period sales went up by only about 7%.
What to do instead
You don't need a big discount to have a good November. Some of the Irish shops we work with are promising their prices won't drop on Black Friday, so customers have no reason to wait. Others offer free delivery, longer returns or early access to the January sale instead of a price cut.
The long game is traffic that doesn't need a discount at all: people finding you on Google because you have exactly what they're searching for. That's what we build for Irish Shopify stores.
