When I am deciding how much to tip at a restaurant, I do not start with the payment terminal. I start with the printed or digital check. I want to know the pre-tax subtotal, the tax, and whether the restaurant has already added a mandatory service charge or automatic gratuity.
For U.S. sit-down restaurant service, Emily Post currently lists 15–20% of the pre-tax bill as a general guideline. I use that as my reference range, then I adjust my own choice from there.
The three lines I check first
I look for:
- the pre-tax subtotal,
- any automatic gratuity or service charge, and
- the sales-tax amount.
If the receipt is straightforward, the calculation is easy. If there is a required charge, I stop before adding another percentage.
Suppose the receipt shows a $90 subtotal, $7.20 tax, and no service charge. If I choose 20%, the voluntary tip is $18.00. The Restaurant Tip Calculator lets me keep all of those amounts visible rather than hiding them in one total.
Why I usually calculate from the pre-tax subtotal
Emily Post expresses its current sit-down restaurant guideline as 15–20% pre-tax, so that is the base I normally use when I want to follow that convention.
If the subtotal is $80:
- 15% = $12.00
- 18% = $14.40
- 20% = $16.00
- 22% = $17.60
I can compare those rates without involving the local tax amount.
Some diners prefer to calculate from the after-tax total. I do not treat that as the same calculation. If I want to see the difference, I use the Tip Calculator With Tax and compare both bases directly.
Automatic gratuity is where I slow down
For larger groups, the restaurant may add an automatic gratuity or service charge. If I see one, I do not assume it is just a suggested tip.
The IRS distinguishes voluntary tips from mandatory service charges for federal tax purposes. I use that distinction on the receipt: a required amount goes into the service-charge field, and any additional amount I choose goes into the voluntary-tip field.
For example, if an 18% automatic charge is already on a $150 subtotal, that is $27. If I then add another 20% without noticing the charge, I add $30 more. I want to know I am adding $57 between those two lines before I approve the payment.
I explain that check in more detail in Automatic Gratuity Explained.
Suggested tip buttons are not the receipt
A payment terminal may show 18%, 20%, and 25% buttons. I treat those as shortcuts, not as evidence of what has or has not already been charged.
If I care about the exact amount, I compare the suggested dollar value with the subtotal. That tells me whether the terminal is using the pre-tax subtotal, the taxed amount, or another base.
I prefer seeing the math myself because it turns a vague “20%” button into an actual dollar decision.
When I am dining with a group
If everyone ordered roughly the same amount, I calculate the full bill and use the Split Bill Calculator for an equal split.
If the orders are obviously different, I do not force an equal split. I enter each person’s items in the Uneven Split Bill Calculator and allocate shared dishes separately.
That approach also helps with tax and tip. I can allocate them proportionally to spending instead of making the person with the cheapest meal subsidize the person with the most expensive order.
What I do with coupons and discounts
A discount creates a choice about the tip base. If a $100 meal is discounted to $80, I decide whether I want to calculate the tip from $80 or from the original $100 service value.
I do not let the calculator pretend there is one etiquette answer. I make the base explicit and enter the amount I actually want to use.
Gift cards are different in my mind because they are a payment method. If I pay part of the bill with a gift card, the underlying restaurant service did not suddenly become cheaper.
Buffet service is a different reference point
Emily Post lists 10% of the pre-tax bill for buffet wait service. That is one reason I avoid saying “20% everywhere.” The service model matters.
The same goes for bars, delivery, salons, taxis, and other services. The How Much Should You Tip? guide compares those categories in one place.
If the service was poor
I do not use a calculator as a substitute for resolving a real service problem. If there is a serious issue with the meal, billing, or service, I address it with the restaurant first.
The calculator is for the moment after I have decided I want to leave a voluntary amount and need the math to be clear.
My restaurant checkout routine
At the end of a meal, I usually do this:
- I find the pre-tax subtotal.
- I check for automatic gratuity or another required service charge.
- I decide what voluntary percentage or dollar amount I want to leave.
- I verify whether I am calculating before or after tax.
- I calculate the final total.
- If I am with a group, I choose equal or itemized splitting.
That takes only a few seconds once the receipt is clear. The step I care about most is the service-charge check, because a perfect percentage calculation is still wrong for my intent if I overlooked an amount that was already included.
