(NEXSTAR) – Are you a pre-tax tipper or do you use the total bill to figure out gratuity? While most people have a mental math trick (or a cellphone) to figure out the tip, diners are divided on what amount on the bill actually deserves one.

Some will only tip on the pre-tax subtotal, maintaining that any state and local taxes that are tacked onto the bill shouldn’t be part of the equation when considering how much to give to restaurant employees.

While doing that math might seem tedious with a smaller bill, one diner on Reddit said their approach changes to pre-tax when it’s a large party or expensive restaurant: “It’s no big deal, until you get into triple digits. Then it starts to matter.”

Another factor, of course, is the tax rate. The combined state and average local sales tax rates for 2023 were well above 8.5% in California, Oklahoma, Alabama, Washington, Arkansas, Louisiana, and Tennessee, while Alaska, Oregon, New Hampshire, Montana, and Delaware have no sales tax. Even in states without sales tax, however, other restaurant-related taxes or surcharges may show up on your bill.

Other diners choose to use the total bill, with some saying they prefer to give more, not less to their servers in most situations. Still, others say simplicity is the goal.

“It’s more trouble than it’s worth to me to figure out the difference between pre and post tax,” another Redditor wrote. “I just figure out 20% of the total which is easy to do.”

But what about tipping screens?

The tipping screen is hard to avoid these days, and while it has been documented to multiply the dollars flowing into the hands of service industry employees, it has also been a source of anxiety and even anger for some consumers.

But when it comes to restaurant bills, don’t the suggested tip amounts get calculated based on the pre-tax total? Not necessarily.

“Sellers decide whether tips are calculated before or after taxes,” a spokesperson for popular payment platform Square told Nexstar.

The Square app also allows restaurant owners and other merchants to enter custom-suggested percentage amounts.

What do experts suggest?

According to the etiquette experts at the Emily Post Institute, tipping at a sit-down restaurant or buffet should be calculated on the pre-tax total (15%-20% and 10%, respectively).

“For large parties this can be quite different than the total,” they note.

Just as important as the tip, the Emily Post experts say, is to always treat servers with respect:

Leaving a generous tip doesn’t make up for ordering someone around or treating them dismissively. While tipping augments servers’ incomes and rewards them for a job well done, treating them kindly is just as important.

Emily Post Etiquette

It deserves mentioning, the guidance is not the same for takeout orders.

Ted Rossman, a senior industry analyst at Bankrate.com, told The Hill that it’s acceptable not to tip when picking up your bagged food at the restaurant. One should still consider giving a tip for large and complicated orders, Rossman said.

Emily Post experts agree that there is no obligation to tip on to-go orders, but a 10% tip is appropriate for difficult orders or curb delivery.

Alix Martichoux contributed to this report.