About Citrus Carton
Checkout maths, done properly: what a discount really saves, what a deal really costs, and what's tax.
What it is
Citrus Carton is six small calculators for the sums that come up when you shop: percent off, discounts stacked on top of each other, buy-one-get-one-free and other multi-buys, the original price behind a sale price, sales tax and VAT, and tips split between friends. Each page shows its formula and a worked example, so you can check the answer yourself.
How it works
Everything runs in your browser. The formulas are part of the page, so nothing you type is sent anywhere, and once a page has loaded it keeps working without a connection. There are no accounts, cookies or ads.
What it is not
It is not a price checker or a tax adviser. It doesn't know what any shop charges or which tax rate applies to your purchase: it works with the numbers you enter. The tax rates on the sales tax page are published standard rates given as examples, with links to the tax authorities; rates change, so check the current one before you rely on it.