You are about to knock money off your price to win a client or move more stock. Before you do, you need two numbers: the discount percentage you are offering, and what that discount costs you in profit. They are never the same number, and the second one is always worse. This guide shows you how to calculate both, with a worked example and a table that tells you exactly how much extra work each discount forces on you.
What does a discount percentage actually measure?
A discount percentage measures how much of your price you give away: the price reduction divided by the original price, times 100. It does not measure what the discount costs you in profit. That cost is always larger, because the full amount you cut comes straight out of profit, never out of costs.
This distinction is the whole reason discounts go wrong. Your costs stay exactly where they were when the price drops. A subcontractor still charges you the same day rate, your software subscriptions do not get cheaper, and materials still cost what they cost. The discount comes entirely off the top of your profit.
Searchers usually arrive here with one job: they are about to offer a discount and want to know exactly what percentage they are giving away and what it costs them, so they can price the discount without working for free. This guide answers that job in order.
How do you calculate a discount percentage?
The short answer: divide the amount you are cutting by the original price, then multiply by 100. The formula is simple:
Discount % = (original price – sale price) / original price x 100
Say your list price is 120 pounds and you agree to charge 96 pounds. The reduction is 24 pounds. Divide 24 by 120 and you get 0.2, so the discount is 20 percent. Working the other way, a 20 percent discount on a 250 pound invoice takes 50 pounds off, leaving a sale price of 200 pounds:
Sale price = original price x (1 – discount / 100)
Stacked discounts do not add up the way people expect. Two discounts of 20 percent and then 10 percent are not a 30 percent discount. The second discount applies to the already-reduced price: 0.80 x 0.90 = 0.72, so you are giving away 28 percent in total. Whenever you combine offers, promo codes, or a negotiated cut on top of a seasonal sale, multiply the remainders and check the real total before you agree to anything.
Tip: work in decimals when you stack discounts. A 20 percent discount leaves 0.80, a 10 percent leaves 0.90, and 0.80 x 0.90 = 0.72 of the original price. It takes five seconds on your phone and stops a painful surprise.
Why does a discount shrink profit faster than price?
Because profit is the thin slice on top of your costs, and the discount eats that slice first. A 20 percent discount on a job with a 40 percent margin does not cut your profit by 20 percent. It cuts it in half.
Here is the worked example with every step shown. Assumptions: UK freelancer, a fixed-price project, costs known in advance, and the discount is a straight price cut with no change to the scope or costs.
You quote 2,500 pounds for a project. Your costs are 1,500 pounds: a subcontractor at 1,100 pounds plus 400 pounds of software and overhead. Your profit is 2,500 – 1,500 = 1,000 pounds, a margin of 40 percent.
- Client asks for 20 percent off: 2,500 x 0.80 = 2,000 pounds sale price
- Costs stay at 1,500 pounds, nothing about the job changed
- New profit: 2,000 – 1,500 = 500 pounds, down from 1,000 pounds
- Profit lost: 500 / 1,000 = 50 percent of your profit, from a 20 percent discount
- New margin: 500 / 2,000 = 25 percent, down from 40 percent
Half the profit is gone, and you still do the same work. For contrast, a 10 percent discount on the same job: 2,500 x 0.90 = 2,250 pounds, profit 750 pounds, margin 33 percent. A 10 percent discount took 25 percent of the profit. The pattern is the same every time: the discount percentage and the profit percentage lost are different numbers, and the profit one is always bigger.
This faster-than-price shrinkage is called margin erosion: your margin percentage falls much harder than the discount percentage, which is why a promotion can leave you busier while paying you less.
The general rule is short enough to remember. The fraction of your profit a discount destroys equals the discount divided by your margin. A 20 percent discount on a 40 percent margin wipes out 20/40 = half the profit. The same 20 percent discount on a 20 percent margin wipes out 20/20 = all of it. If you are unsure whether you are thinking in margin or markup, our guide to profit margin vs markup sorts the two out with worked formulas.
Watch out: never confuse “discount percent off the price” with “margin points lost”. If your margin is 30 percent and you give 10 percent off, you lose a third of your profit, not a tenth. Freelancers who price by feel almost always underestimate this.
How much extra work does a discount force you to do?
Every discount has to be paid for somehow. If the discount brings you new volume, the extra work can cover it. If it does not, you just earn less for the same hours. The question to answer before you agree is: how much more do I need to sell to end up with the same money?
The formula uses the same two numbers, margin and discount:
Extra work needed (%) = discount / (margin – discount) x 100
If the discount equals your margin, the bottom of the fraction is zero and no amount of extra work ever covers it. That is the mathematical version of “you are working for free”.
The table below shows the answer for common margins and discounts. Every figure comes from the formula above, so you can read off your own situation. Row = your margin before the discount, column = the discount you are thinking of offering. LancerBill’s profit margin calculator gives you your margin in seconds if you have not worked it out yet.
| Your margin | 5% discount | 10% discount | 15% discount | 20% discount |
|---|---|---|---|---|
| 20% | 33% more work | 100% more work | 300% more work | Never breaks even |
| 30% | 20% more work | 50% more work | 100% more work | 200% more work |
| 40% | 14% more work | 33% more work | 60% more work | 100% more work |
| 50% | 11% more work | 25% more work | 43% more work | 67% more work |
Read the 20 percent margin row again. On a 20 percent margin, a 20 percent discount means you work for nothing, and a 10 percent discount halves your profit, forcing you to do twice the work to stand still. Thin-margin work simply cannot carry big discounts.
Use this table as a sanity check in negotiations. When a client pushes for 15 percent off and your margin is 40 percent, you now know the price of yes: 60 percent more work to end up in the same place. If the client cannot bring 60 percent more business, the answer is a smaller discount or a narrower scope.
What is the biggest discount you can safely offer?
The absolute ceiling is your margin. If your margin is 40 percent, a 40 percent discount leaves you at zero profit, and anything bigger means you are paying to do the work. The formula:
Maximum discount = 1 – (costs / price)
On the worked example above: 1 – (1,500 / 2,500) = 0.40, so 40 percent is the point of zero profit. In practice you want a floor, not a ceiling. If you need a minimum margin of 25 percent on every job, the biggest discount you can offer is:
Maximum discount = 1 – (costs / (price x (1 – minimum margin)))
For the same job with a 25 percent minimum: 1 – (1,500 / (2,500 x 0.75)) = 1 – (1,500 / 1,875) = 0.20. So 20 percent off is the most you can give while keeping a 25 percent margin, and it lands exactly at that floor. Set your floor before the negotiation starts, not during it.
Tip: write your floor discount on a sticky note before every pricing call. Clients negotiate; a number you set in advance negotiates less badly than one you invent under pressure. Run any proposed price through LancerBill’s discount calculator before you say yes.
Which discounts earn their keep and which quietly cost you?
Not every discount is a mistake. The test is whether the discount buys you something worth more than the profit it destroys. If you have not priced your floor yet, LancerBill’s freelance rate calculator gives you the number you are defending. Run each discount through this decision framework before you offer it.
Early-payment discounts. Offering 2 percent off for payment within 10 days (the classic 2/10 net 30) trades a small, known cut for faster cash flow. It is usually worth it when clients pay late anyway. Our guide to invoice payment terms explains how 2/10 net 30 works and when it pays off.
The repeat-client trap. This is the discount that keeps costing. A client who got 10 percent once opens the next conversation from the discounted price, so the discount quietly becomes your new rate for that client. The cost is not one job, it is every job after it. If you discount for a returning client, put the full price on the invoice and show the discount as a separate line marked “one-time loyalty discount”. Paperwork like that resets expectations.
Introductory offers for new business. A discount can win a first project that leads to full-price work. Price it as a marketing cost: the profit you give up is what you are paying to acquire the client. If the client stays at the discounted rate forever, you bought nothing.
Stacked discounts. A seasonal 15 percent plus a 10 percent promo code is not 25 percent, it is 23.5 percent, and nobody audits the combination until the margin is gone. Check the real total with the stacking method above before you launch a promotion.
Retainer discounts. Cutting your rate in exchange for a guaranteed monthly retainer can be the best trade in freelancing, because it replaces unpaid pitching and dry months. But discount the rate only against real, signed, recurring volume, never against a promise of “lots of work coming”. When you are deciding what rate to protect, the framework in how much to charge as a freelancer helps you set your floor first.
One more hidden discount to watch: platform fees. If a marketplace takes 10 percent of your invoice, that is a discount you did not choose. Our freelance platform fee comparison shows what each platform really takes, so you can price it in instead of absorbing it.
Watch out: “we will make it up on volume” is a plan with a specific volume in it, and that volume is usually larger than anyone guesses. Make the client name the extra business before you give the discount, then check it against the table above.
Key takeaways
- Discount % = (original price – sale price) / original price x 100. Stacked discounts multiply, they do not add: 20% then 10% is 28%, not 30%.
- A discount always costs you more in profit than in price. The profit destroyed equals discount / margin, so 20% off on a 40% margin halves your profit.
- Extra work needed (%) = discount / (margin – discount) x 100. On a 20% margin, a 10% discount forces you to do twice the work to stand still.
- Your maximum discount is your margin. Set a minimum-margin floor before negotiations, not during them.
- Show one-off discounts as a separate invoice line so they never become your permanent rate, and audit stacked promos for their real total.
Frequently asked questions
How do you calculate a discount percentage from the original and sale price?
Subtract the sale price from the original price, divide by the original price, and multiply by 100. If an item was 120 pounds and now sells for 96 pounds, the discount is (120 – 96) / 120 x 100 = 20 percent. LancerBill’s discount calculator runs this instantly for any two prices.
Is a 20 percent discount the same as losing 20 percent of your profit?
No. A discount comes entirely out of profit because your costs do not fall when the price does. The profit you lose equals the discount divided by your margin. On a 40 percent margin, a 20 percent discount destroys half your profit. On a 20 percent margin, the same discount wipes it out completely.
How many extra sales do I need to cover a discount?
Use: extra work needed (%) = discount / (margin – discount) x 100. A 10 percent discount on a 40 percent margin needs 33 percent more sales to leave you with the same total profit. On a 30 percent margin, the same discount needs 50 percent more sales. If the discount equals your margin, no amount of extra sales ever covers it.
What is the maximum discount I can offer without losing money?
Your margin is the ceiling: 1 – (costs / price). Beyond it, you are paying to do the work. Set a minimum-margin floor and compute the maximum discount that preserves it, and never offer a discount without knowing both numbers.
Do stacked discounts add up?
No. Each discount applies to the already-reduced price, so you multiply the remainders. A 20 percent discount followed by 10 percent gives 0.80 x 0.90 = 0.72 of the original price, which is a 28 percent total discount, not 30 percent.
Should I give repeat clients a discount?
Only as a clearly one-off gesture. A discount that repeats becomes your new rate for that client, costing you profit on every future job. Put the full price on the invoice and show the discount as a separate “one-time loyalty discount” line, so the original price survives the negotiation.
This guide is for general information only and is not financial, tax or legal advice.