Tipping before or after sales tax: what the difference actually is

The question is which number the percentage multiplies

A restaurant bill in a place with sales tax has three parts: the food and drink, the tax added on top, and the tip. Everyone agrees the tax is added once. The disagreement is narrower than it looks: when you take 20%, do you take it on the food and drink, or on the food and drink plus the tax?

That is the whole question, and it has an exact answer rather than an opinion. Our Tip calculator has a control for it, so you can see both sides of the same bill instead of arguing about which is meant.

One bill, both ways

Take an $80 bill, an 8.875% sales tax and a 20% tip. The tax is $80 × 0.08875 = $7.10 either way — it is charged on what you bought, and nothing about the tip changes it.

• Tip before tax: 20% of $80 is $16.00. Total: $80 + $7.10 + $16.00 = $103.10.
• Tip after tax: 20% of $87.10 is $17.42. Total: $80 + $7.10 + $17.42 = $104.52.

The difference is $1.42. Not a rounding error, and not a scandal either — on a $103 evening it is about one and a third percent of the total.

The shortcut: the gap is your tip percentage of the tax

You never have to compute both. Tipping after tax means tipping on an extra $7.10, so the difference is simply 20% of $7.10 = $1.42. That is the whole rule: the gap between the two methods is the tip percentage applied to the sales tax, and nothing else.

It scales the way you would expect. At a 6% tax rate the same $80 bill carries $4.80 of tax, so a 20% tip differs by $0.96 between the two bases. At a 4% rate it is $0.64. The lower the tax, the less there is to argue about — and in a place with no sales tax at all, the two methods are identical, which is why the calculator's tax field starts at zero and the two bases then give the same answer.

There is a second way to read the same fact. Tipping 20% on the post-tax total is arithmetically the same as tipping 21.775% on the pre-tax bill at that tax rate. If you want a specific percentage to reach the staff, the pre-tax base is the one that says what you mean; if you would rather not think about it, the difference is a dollar or two on a normal meal.

Try it on your own bill

The calculator keeps the bill you enter as the pre-tax amount and adds the tax exactly once, whichever base you pick, so the two results differ only in the tip. Open the same scenario tipping before tax and then tipping after tax and compare the totals — the split bar shows the bill, the tax and the tip as three separate amounts rather than one number to accept.

Sales tax, tip and service charge are three different things

They land on the same piece of paper and behave completely differently, which is where most of the confusion starts.

• Sales tax is a tax on the sale, set by the jurisdiction and collected by the restaurant. Neither you nor the restaurant chooses the rate, and it goes to the government.
• A tip is money you choose to add, in an amount you choose. Under the federal Fair Labor Standards Act an employer — including a manager or supervisor — may not keep any portion of an employee’s tips for any purpose, whether directly or through a tip pool. Valid tip pools between employees are allowed, and who may take part in one depends on whether the employer claims a tip credit against the minimum wage.
• A service charge is an amount the business adds to the bill and sets itself. It is revenue of the business, not a tip in the legal sense, even when it is described on the menu as going to staff.

That last one is worth care rather than cynicism. Service charges are not all the same thing. A large-party gratuity added automatically, a flat kitchen-appreciation fee, a delivery charge and a mandatory service charge at a venue that pays a higher base wage are different arrangements with different destinations, and a good restaurant will tell you which it is if you ask. What they have in common is only that they are set by the business rather than by you.

Practically: if a service charge is already on the bill, decide what you want the total to be first, and treat anything you add as being on top of a charge that has already been made. Entering the post-charge total into a tip calculator and applying a full percentage to it will tip on the charge as well.

Where this question does not arise

The pre-tax-or-post-tax argument is specific to places where tax is added at the till. In the EU, consumer price rules require the selling price shown to a consumer to be the final price including VAT, so the number printed on the menu is the number you are tipping on and there is no second base to choose. That is one reason a percentage that feels normal in one country reads as strange in another — the base is not even the same kind of number.

The customary percentage itself is a separate question, and it is not one arithmetic can settle. Our tipping guide covers what people actually leave in 22 countries, including where a service charge usually appears on the bill already.

So which should you use?

Either is defensible, and the amount at stake on an ordinary meal is a dollar or two. What is worth avoiding is the accidental version: tipping on a total that already includes a service charge, or entering a tax-inclusive total and then adding tax again. Both of those cost far more than the pre-tax-versus-post-tax gap.

If you want a rule: take the percentage on the pre-tax bill, because that is the number that describes the meal, and round the total up if you want to be generous. If you tip after tax instead, know that you are giving roughly your tip percentage of the tax as well, and that on an $80 bill at 8.875% that is $1.42.

• Fact Sheet #15: Tipped Employees Under the Fair Labor Standards Act (FLSA) — U.S. Department of Labor, Wage and Hour Division
• Tip Regulations under the Fair Labor Standards Act (FLSA) — U.S. Department of Labor, Wage and Hour Division
• Directive 98/6/EC on consumer protection in the indication of prices (selling price includes taxes) — EUR-Lex, Publications Office of the European Union