Is That Sale a Good Deal?
“40% off then another 20% — is that better than 50% off?”
40% off and then another 20% at the till is 52% off, not 60% — because percentages multiply rather than add. Stack up the offers, the voucher, the delivery and the tax, and get the one number that leaves your account.
- Stacked percentages worked out properly, with the gap from the sign spelled out
- Buy-one-get-one, three-for-two and multi-buys turned into a real per-item price
- Delivery and free-delivery thresholds counted, because they undo small discounts
- Tells you when the order the shop applies a voucher in is costing you money
- Compares against a price elsewhere, all in, like for like
Opens in a new tab. Downloading is optional — do it if you want it on your machine for good.
- The whole tool — not a trial or a cut-down version
- Works offline forever once it's on your machine
- Nothing you type is stored, sent, or tracked
- If it's useful, the other 47 are $9 each
Three steps, then you're done
And how many you're really buying.
Percentages, vouchers, multi-buys.
What you'll actually pay, not what you'll 'save'.
Questions
Do I need to install anything?
No. Each tool is a single file. Double-click it and it opens in Chrome, Edge, Safari or Firefox — whichever you already have. No account, no password, no software.
Does anything get uploaded?
No. Your numbers and files never leave your computer — the tools have no way to send them and no internet connection is needed to run them. You can switch your wi-fi off and they still work.
I'm not good with computers. Is this too hard?
The first thing every tool does is walk you through it in five short screens with pictures. Then there's a button that fills it with example numbers so you can watch it work before touching anything.
Will it work on my phone?
Yes. Email yourself the file and open the attachment, or drop the files in iCloud Drive, Dropbox or Google Drive and open them from there — then they're on every device you own.