What is a tip?
A tip, gratuity, or service tip is an additional amount paid to recognize service. The calculation itself is a percentage problem: convert the chosen percentage to a decimal, multiply it by the appropriate bill base, and then add the tip to the amount you pay.
The important detail is what the percentage is applied to. If the bill has a separate tax line, some tipping customs use the pre-tax subtotal while others use the tax-inclusive amount. A service charge may also already be included, so reading the receipt is part of the calculation.
Why percentages matter
Ten percent is a useful mental benchmark because it is one tenth of the bill. Twenty percent is twice that amount. Fifteen percent is halfway between 10% and 20%. This makes quick estimates possible even without a calculator.
Tip formulas
Tip = base × (tip % / 100)Total = subtotal + tax + tipEach = total ÷ peopleTip/person = tip ÷ peopleWhen Include tax when calculating tip is off, the base is the subtotal. When it is on, the base is subtotal + tax. This distinction is why the calculator asks for tax separately instead of hiding it inside the bill.
Worked examples
Tip = $86.40 × 0.15 = $12.96.
Total = $86.40 + $12.96 = $99.36.
Each person = $99.36 ÷ 2 = $49.68.
Subtotal $86.40 + tax $8.64, with a 15% tip on the subtotal: tip = $12.96; final total = $108.00. If the same 15% is applied to the tax-inclusive base, the tip becomes $14.26.
Tipping customs around the world
Tipping is a local convention rather than a universal percentage. Use the map as a quick orientation, then read the bill itself: a service charge, automatic gratuity or included service can change what an additional tip means.
Three questions before you tip
Is service already included?
Look for wording such as service charge, gratuity or service included before adding another amount.
What kind of place is it?
A hotel, café, casual restaurant and fine-dining venue can follow different local conventions even in the same country.
What does the local custom suggest?
Use the map for context, then choose a percentage or rounded amount that matches the actual bill and setting.
How to read the bill before tipping
Find the base
Locate the subtotal or service amount before deciding which number the percentage should use.
Look for extras
Check tax and any included service or gratuity so you do not accidentally double-tip.
Choose a percentage
Use the calculator to see exactly what each percentage means in money.
Divide fairly
For an equal split, divide the final total by the number of people sharing the bill.
Tip calculator FAQ
There is no universal rule. Some people calculate the tip on the pre-tax subtotal, while others use the tax-inclusive amount. Check local practice and the bill. The calculator lets you choose either method.
Move the decimal point one place to get 10%, then double it. For $50, 10% is $5 and 20% is $10.
Calculate the total bill including tip, then divide by 4. You can also divide the tip amount by 4 to see each person's share of the gratuity.
Read the wording carefully. A service charge or automatic gratuity can already be part of the final bill. Whether to add anything more depends on the local custom, venue and service.
Yes. Rounding is a payment convenience rather than the exact percentage calculation. The calculator shows the exact tip first, so you can see the difference before rounding.