When going out with friends to a restaurant, often times one person will pay for the whole group and the rest will have to pay them back. There is often confusion regarding how to split the tax and tip accurately, fairly, and consistently among the group.

This app will help you quickly calculate how much of the tax and tip you owe, as well as the final amount you need to pay back the friend who picked up the tab.

The app uses a formula that allocates tax, tip, and other fees proportionally based on the relative size of your purchase, which is the fairest way to split bills (as opposed to, for example, splitting the tax and tip evenly across the group, which would result in people who ordered less subsidizing people who ordered more).

For example, if the items you bought form 10% of the bill subtotal (price sum of all items bought by everyone, before tax, tip, and other fees), then you would also pay 10% of the tax, tip, and other fees, which amounts to paying 10% of the bill total.

The app uses the formula below to help you quickly calculate how much you owe, without relying on a calculator, which reduces mistakes.

Amount owed = ( ( your item 1 + your item 2 + your item 3 + ... ) / bill subtotal ) * bill total

To make sure everyone is on the same page, tell the group that you will be using this app to calculate the amount you will pay back. If everyone in the group uses this app to calculate the amount they owe, this will ensure the host will get paid back correctly, and no one will overpay or underpay.

You can also use the app for splitting bills other than restaurant bills, like itemized shopping receipts, groceries, travel, and other expenses.

The app also provides a tip calculator.