Everyday Math: Ladies, Tip Your Waiters

We’ve all been there – the check arrives, it’s time to figure out the tip, and all of a sudden you can’t remember any of the math you learned in high school. No worries! You don’t need to whip out the calculator on your cell phone to make sure the waitstaff get what they deserve. Here are a few sneaky tricks to figure it out in your head, without having to multiply by any decimals!

If you’re feeling especially generous, the easiest tip to calculate is 20% (whether or not to include drinks or tax is between you and Emily Post). Either divide the total by 5, or drop the last digit from the total and multiply by 2.¬†For example, let’s say the total is $30.00. 30.00 / 5 or 3.00 x 2 = $6.00.

A 15% tip is also relatively easy. Drop the last digit from the total like in the example above, divide that number in half, and then add those two numbers together. For that same $30 ticket, 3.00 + 1.50 = $4.50.

Let’s say you want to tip somewhere between those two numbers. Dividing the total by 6 will give you a 16.7% tip. (30.00 / 6 = $5.00) Or if you want to be fancy and tip exactly 18%, you can still do it without too much trouble. Knock off the last digit, then knock off another digit and subtract this number from the first. This will give you 9% of the total, so double it for 18%. 3.00 – .30 = 2.70; 2.70 x 2 = $5.40.

The same tricks work with any number, not just even dollar amounts (though it may be easier to ignore the change for larger amounts since you’ll likely round the total off to the nearest dollar anyway). Not that bad, was it?

By [E] Hillary

Hillary is a giant nerd and former Mathlete. She once read large swaths of "Why Evolution is True" and a geology book aloud to her infant daughter, in the hopes of a) instilling a love of science in her from a very young age and b) boring her to sleep. After escaping the wilds of Waco, Texas and spending the next decade in NYC, she currently lives in upstate New York, where she misses being able to get decent pizza and Chinese takeout delivered to her house. She lost on Jeopardy.

8 replies on “Everyday Math: Ladies, Tip Your Waiters”

My dad taught me 20% is the default tip (his mom owned a restaurant and his wife/my mom worked there through school), and over here on the west coast, that seems to be pretty standard. 99% of my tips when I was a waitress were 20%, and I can count on one hand the times I was tipped less than that. I guess it depends on where you live, but I just kind of thought we had all agreed 20% as the going rate. When I go out, I do 20% most of the time. Really good service gets 25%, and really bad gets 15%.

Plus, 20% has always been easy for me to figure out. If it’s anything other than that (or 25%) I kind of just guess.

Usually I tip around 20% of the final bill for good service using the drop-a-zero-and-double method you mention. Another easy way to figure out tip is to double the tax, although it really depends on where you live. In my neck of the woods, tax is 9.75%, so it works out to about 19.5% on the pre-tax subtotal, which is a pretty reasonable tip for average service. Some places where the tax is much lower, it is less convenient.

Yes! Sometimes out of sheer laziness I take the bill and the tip because my brain just quit on the math’s functionality and I can’t figure out how to split the bill/and or tip. (Luckily) down here a tip isn’t so .. needed? common? as in the States, so dinner partners and me can just take the bill (“Am I paying today?” -“Yep”)

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