Tipping customs vary by service, location, and situation. This guide explains the arithmetic behind common percentages; it is not a rule about what any individual must leave.
Calculate a percentage of the bill
For an 18% tip on an $86 bill, calculate 0.18 × 86 = $15.48. The total is $101.48 before any further adjustments.
Use 10% as a mental anchor
Ten percent of $86 is $8.60. For 20%, double it to $17.20. For 15%, add half of 10% to 10%, giving $12.90.
Check whether gratuity is included
Some restaurants add a service charge or automatic gratuity, especially for larger groups. Review the receipt before adding another amount.
Decide which bill amount to use
People differ on whether they calculate tips before or after tax. The calculator can use whichever bill amount you choose; clarity and consistency matter more than pretending there is one universal rule.
A calculator is often the quickest way to check your mental math. The important part is using the right starting value.
Open a calculator →Common questions
How much is a 20% tip on $50?
$10, making the total $60.
What if a service charge is already listed?
Read the receipt and venue policy so you understand what the charge covers before adding more.
Can I round a tip?
Yes. Many people round to a convenient total as long as the result matches their intention.
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