Price & marginFree
Black Friday Calculator
Shows whether your Black Friday promotion makes a profit. Compares a normal month with the Black Friday scenario (discounted price, volume multiplier and remaining margin), lists scenarios from 10% to 50% off side by side and points out the deepest sustainable discount.
- No sign-up
- Runs in your browser
Normal month
Black Friday scenario
How to estimate the volume multiplier
- Impulse purchases (fashion, beauty): 5× to 10× on Black Friday
- Planned purchases (electronics, furniture): 3× to 6×
- Recurring purchases (supplements, pet): 2× to 4×, because consumption is already steady
If you have run Black Friday before, use your history. If it is your first time, stay at the low end of the range: overestimating volume is the most common mistake.
Costs this calculator does not consider
- Extra media spend (use the ROAS calculator)
- Operating costs (staff, extra packaging)
- Opportunity cost (stock reserved instead of other channels)
- After-Black Friday effect (customers get used to the discount)
How it works
How to calculate Black Friday profit
The calculator compares your normal month (baseline) against the Black Friday scenario. For each discount it runs: BF profit = (discounted price − cost) × projected units, where units rise by a volume multiplier. The discounted price is full price × (1 − discount), and the residual margin is what's left after the cut. That shows whether the extra volume covers the margin you gave up.
Example: a R$ 200 product costing R$ 120 leaves R$ 80 of margin. With 30% off, the price drops to R$ 140 and margin becomes R$ 20 per unit. If you sold 100 a month and volume triples to 300 during BF, profit goes from R$ 8,000 (baseline) to R$ 6,000: you sold more and earned less. Only with 4x volume (400 units) do you match the original profit.
That's why the tool lays out the 10% to 50% off scenarios side by side and flags the maximum sustainable discount: the one where a realistic volume multiplier still keeps profit above baseline. Discounts that demand impossible volume (5x, 6x) usually mean burning margin for nothing; better to hold at 20% to 30% and protect your cash.
FAQ
Frequently asked questions
What is the Black Friday Calculator?
It's a free tool that shows whether your Black Friday promotion will actually be profitable. It compares your monthly baseline against the BF scenario (discounted price × volume multiplier × residual margin) and runs 100% in the browser, no signup.
How do I calculate whether a Black Friday discount is worth it?
BF profit = (discounted price − cost) × expected volume. The calculator applies this across 10% to 50% off scenarios side by side, factoring in the volume multiplier each discount drives, and pinpoints the deepest discount that still protects your margin.
What's the difference between the shelf discount and residual margin?
The shelf discount is the % the customer sees (e.g. 30% off); residual margin is what's left per sale after cost and the discount. A steep discount can sell a lot yet still melt your residual margin — the tool shows both side by side.
What's the maximum discount I can offer on Black Friday?
The maximum sustainable discount is the deepest % off that still keeps the BF scenario more profitable than your monthly baseline. The calculator finds that point automatically by weighing the extra volume against the margin you give up at each tier from 10% to 50%.
Is the Black Friday Calculator free?
Yes, it's 100% free and runs right in your browser, with no login or install. You enter cost, price, margin and expected volume, and instantly see the discount scenarios compared against your baseline.
Blog
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