Tip calculator and bill splitter

The math, and shortcuts for your head

Tip = bill × tip percent ÷ 100. Total = bill + tip. Each pays = total ÷ people. For a $120 bill, a 15% tip and four people, the tip is $18, the total $138, and each pays $34.50.

Without a calculator, start from 10%, which is the bill with the decimal point moved one place to the left:

• 10% of $86.40 is $8.64.
• 20% is double that: $17.28.
• 15% is 10% plus half of it: $8.64 + $4.32 = $12.96.
• 18% is 20% minus a tenth of 20%: $17.28 − $1.73 = $15.55.

Another quick habit is to work out the total with tip and round it up to a whole dollar: $86.40 with 15% is $99.36, so leave $100. In Octoolo's calculator the percent key does the whole split in one line: (120 + 15%) ÷ 4 gives 34.5.

Before tax or after tax?

Etiquette guides commonly suggest tipping on the subtotal before tax, since tax is not part of the service. The difference is usually small. On an $80 meal in New York City, where sales tax is 8.875%, tax adds $7.10: a 20% tip is $16.00 on the subtotal or $17.42 on the total with tax.

To tip on the subtotal but split the whole check, enter the subtotal as the Bill and note the Tip, then add the tax to the Total yourself and divide by the number of people. With the numbers above and four people, that is ($96.00 + $7.10) ÷ 4 = $25.78 each.

Check the receipt for a service charge or automatic gratuity first, which many restaurants add for large groups. If it is there, set Tip to 0, or to whatever extra you want to leave.

Splitting fairly when orders differ

An even split is quick and fair when everyone ordered about the same. When they did not, share the tax and the tip in proportion to what each person ordered: if Sam's dishes were $30 of a $90 subtotal, Sam pays a third of the tax and tip as well.

The quickest way is to multiply each person's items by one number. With 8% tax and a 20% tip on the subtotal, everyone pays their items × 1.28. Sam owes 30 × 1.28 = $38.40, and the shares of the whole table add up to the full amount: $90 × 1.28 = $115.20.

Rounding is the other snag. A $100 bill with an 18% tip split three ways is $118 in total, or $39.33 each, which adds up to $117.99. Someone has to pay the extra cent. Rounding every share up to $39.50 instead leaves a little more for the server. If one person paid the whole bill, Each pays is what everyone else sends them.

How much to tip

Customs vary by country, and this is general background rather than a rule:

• United States and Canada: 15% to 20% is the common range at sit-down restaurants, more for great service, often less at a counter.
• United Kingdom: many restaurants add a discretionary service charge, often 12.5%; where they do not, around 10% is usual.
• Much of continental Europe: service is usually included in the prices, and rounding up or leaving a few coins is common.
• Japan: tipping is not customary and can cause confusion.

Whatever percent you choose, the answers update as you type, so trying 15, 18 and 20 takes a few seconds. The same split works for shared costs that have nothing to do with tipping: set Tip to 0 to divide a rental, a gift or a fuel bill evenly.