June 15, 2013

A Math Hater's Guide to Restaurant Tipping

Learning math was easy... until my first grade teacher introduced us to that crazy "carry the one" stuff when adding double digits. And don't even get me started on how shocked I was when the teacher first explained the existence fractions and negative numbers. (How could there be a number smaller than zero?)

Courtesy: drewsmarketingminute.com
But as a confessed math hater, I will concede that there are a few situations in life where it is handy to know how to do some basic math. No, not calculus (whatever that is) -- just simple addition. One such instance is when you eat in a restaurant, and it's time to pay your bill.

Restaurant servers generally seem to be an underpaid and under-appreciated bunch. So I try to be a good tipper unless something horrible happens. By doing so, I'm helping out someone who has a tough job and, selfishly, I'm making my life a little easier by not having to do so much math. When in (mathematical) doubt, I always round up.

So the first step when the bill comes is to figure out how much to tip. Let's say the bill is $38.69. Don't even ask me to try to calculate what 15% or 20% of $38.69 is. Instead, what I do is look at the amount of sales tax on the bill. In this case, it would be $3.19 because the sales tax rate where I live is 8.25%.

So if I double the amount of sales tax on the bill, that will give me a 16.50% tip which is within the acceptable range. Doubling $3.19 in my head is easy enough, even for me. Three times two is six, and I would round the 19-cents up to 20 since doubling 20 is easier than doubling 19. Are you still following me?

Therefore, my first inclination would be to add a tip of $6.40 to the credit card receipt. But I can't stop there because, remember, the total bill amount is $38.69, so I wouldn't want to have to to add 40-cents plus 69-cents and "carry the one" in my head (or on paper). So I'll save myself the trouble and just knock the tip amount up to $7 and not have to mess with the cents column at all.

As for adding $38 plus $7, I can do that easily on my fingers if needed (and with my hand in my lap or under the table so nobody notices). Voila! The server would get a $7 tip, and my total credit card bill would be $45.69.

It's a convenient, albeit sad and pathetic, way for a math hater to calculate a tip. Any questions?


  1. I absolutely follow your logic! I've spent my life doing math the "wrong" way, so it's nice to see that someone else takes strange detours on what others would consider simple problems.

    1. It's good to know we're not the only ones out there!