To estimate your yearly voucher savings, multiply the orders you place in a year by your average basket, by the share of those orders where you actually find a working code, by the average discount. Two £60 orders a month with a code on most of them might save somewhere around £85 to £145 a year, depending on how often a code really applies. The calculator above does the sums for you; this guide explains how to choose sensible inputs.
The annual voucher savings formula
Orders per year × average basket × share of orders with a code × average discount = estimated yearly saving.
The third figure is the one most estimates skip. Plenty of orders have no code, or the code excludes what you are buying, or the minimum spend is out of reach. Being honest about that share keeps the result believable.
This page is about shopping savings from vouchers and deals. It is not a bank savings or interest calculator, so there is nothing here about ISAs or interest rates.
Worked examples
| Shopper | Orders a year | Average basket | Orders with a code | Average discount | Yearly saving |
|---|---|---|---|---|---|
| Occasional | 12 | £70 | 50% | 10% | £42.00 |
| Regular | 24 | £60 | 60% | 10% | £86.40 |
| Frequent, smaller baskets | 36 | £45 | 40% | 12% | £77.76 |
How the regular shopper's figure works
Twenty-four orders at £60 is £1,440 of spending. A code on 60% of orders covers £864. At 10% off, that is £86.40.
If you assumed a code on every order, you would get £144, which is about two-thirds higher. That gap is why the "share with a code" input matters.
Percentage off or pounds off?
A fixed amount off is worth more on small baskets, and a percentage is worth more on big ones. £10 off £50 is 20%, but £10 off £100 is only 10%. When you have a choice, the Voucher Comparison Calculator shows which is better for your basket.
If a sale price and a code can be combined, the Stacked Discount Calculator works out the final price. To check a single deal, use the Discount Calculator.
Add the extras that vouchers often sit alongside
- Cashback: if a retailer also pays cashback, it comes on top of the code. As an illustration, 10% off a £60 basket leaves £54, and 3% cashback on that is £1.62. Check how it works in the Cashback & Voucher Calculator.
- Delivery: avoiding a delivery charge is a real saving. See the Free Delivery Calculator for threshold maths.
- Sales: reductions you get from sale prices can be logged in the Sale Savings Calculator, so you can see total savings across the year.
- Unit prices: for groceries and household basics, the Price Per Unit Calculator shows whether a deal is genuinely cheaper.
When a saving is not really a saving
A discount only helps if you would have bought the item anyway. Say a code gives 10% off when you spend £80, and your basket was £60. Adding £20 of extras saves £8, but you now pay £72 instead of £60. You have spent £12 more than planned.
The same applies to chasing a free delivery threshold. Before topping up a basket, compare the extra spend with the delivery fee you would avoid.
How to get realistic inputs
- Count your orders: check your email receipts or bank statements for the last 12 months.
- Use your real basket size: the median order is better than your biggest one.
- Be cautious on the code share: start at 40% to 50% and raise it only if you can show you regularly find codes.
- Track actual savings: note the amount saved on each order for a few months, then replace the estimate with your own average.
Putting the estimate to use
Build a habit of checking for a code before you pay. Codes are usually restricted by minimum spend, product exclusions, new-customer rules or expiry dates, so read the terms before you rely on one. You can browse offers by store or category on PrimeVoucher, then run the numbers here to see whether a deal is worth the effort.
All figures above are illustrations built from the formula, not averages or promises. Your own result depends on what you buy and the offers available at the time.