Tip Calculator: Tip amount for various percentages of the cost of the service is calculated by Tip Calculator or EZ tip calculator and also provides a total amount that includes the tip. A tip of 15% of the before-tax meal price is typically expected in the US. Hence, the tip payment will be equal to the total bill amount multiplied by the tip percentage in a decimal format. As an example, let’s calculate a 40% tip for a $300 bill. Thus, $120 would be a 40% tip on a $300 bill.