Double the tax shown on the bill to edit my answer - GENERALLY this is a quick and easy way to calculate a tip assuming the state you are in HAS tax. If not, I guess your shit out of luck - whip out the calculator. And if you are going to critique someones answer, I think you should supply your own answer as well.

Calculate it based on the sales tax. For instance, where I live the sales tax is 7%. So a 15% tip is about twice the sales tax (7% x 2 = 14%), and a 20% tip is about 3 times the sales tax (7% x 3 = 21%). If you want to leave a 10% tip, just take the final bill and move the decimal point one space to the left. For instance, if the bill is $12.95, a 10% tip will be $1.29. A 20% tip will be twice that, or $2.58.

10% of your bill is the same as moving the decimal point left one place 10% of 24.60 is 2.46 half of 2.46 is 1.23 (so now you know 5% of 24.60) 2.46 (10%) plus 1.23 (5%) = 3.69 (I'm all for rounding up to make things easier too.) If you want to leave 20% just take 10% times two. If the numbers still feel too tricky round until they're something you're comfortable dividing by two. (You may leave a few cents more, but you'll be oh so suave calculating that tip without missing a beat.) Your dinner at a fancy restaurant is $237.62. If you round it to 240.00, take 10% 24.00, halve that 12.00, and add 'em =36.00 (if you'd calculated to the penny you'd save $0.36 and lose a few more valuable seconds of your life.) As you can see, even with a pretty big bill rounding to the next even number won't cost you dearly. Of course in a good restaurant or with good service look more toward doubling 10% than penny pinching 15%. It also helps to have these rules of thumb if you want to give a little more than 15%. In the example above you know that 36.00 is 15% of 240.00 you also know that 5% is 12.00. Now you have a good idea of how much is a little more, but still not quite 20%. By all means, see how well this works for tipping more than 20% whenever you're inclined to do so!

About 30 years ago when I was working in a restaurant, we all agreed that we would never leave what we call a "[expletive deleted] tip," that is, one that was calculated to exactly 15%. When we were out on the town, we rounded up to the nearest quarter. Still a good practice, but even with a small bill it's polite to give a dollar a person, minimum. It's more than polite. It's kind. The server isn't a robot, but a respectworthy individual who has made your experience more pleasant than it would have been at a self-serve cafeteria line. For really bad service, leave a very small tip, rather than none at all. If you leave none at all, the server thinks you're stingy (a "stiff") and sees no relationship between his/her poor service and the tip. Two nickels is ideal, because it says you are intentionally leaving a small tip, not that you're down to your last change. Two pennies would be a positive insult and would never be called for--you'd have walked out if service was that bad.

Your answer is quick and simple. if your total bill is $30, then 10% or $3.00. but, if you had extremely good service or you like your waiter, the sky is the limit. see......simple!

2 ways to figure out 15% is $1.50 for every $10 or $1 for every $7.

I generally round the bill up, after tax, to the nearest dollar and then multiply that by 15%. If the service was really good I'll add more on top of that.

I usually calculate 10% by moving the decimal, then when you double it you have 20%. Then I decide based on the service whether to go with the low number, the high number or somewhere in between. I almost always tip whole dollars. So if the bill is $31.20, 10% is $3.12, 20% is $6.24. I'd probably tip $3 if service was below par, $4 if it was average, $5 if it was pretty good and $6 if it was excellent. If I was ignored completely I leave 1 cent so they know I didn't forget but they get the message.

However you figure it, use the taxless subtotal as your basis.

Double the tax or 20% is easy to calculate. Move the decimal one place to the left then double that..

I never tip. No one tips me to assemble car seats.

The garbage with the sales tax is too complicated. Round the bill either up or down. Dont deal with the change. 10 percent is just a matter of moving the decimal point. That's your base number. Half of that added to it is a 15 percent tip. Twice that is a 20 percent tip. Exceptional service toss in a few bucks over that.

you could just ask the people at the restaurant how much youre supposed to tip

Well figuring out 10% of the bill is super easy and then just split that in half for the other 5% and add them together or double the 10% if you're a good Tipper

Assuming good service I double the total bill number then move the decimal to the left! then you have 20% Example:: Bill is $16 then its 32 then $3.20 (If you want to be a stickler for accuracy double cost before tax)

You shouldn't. Instead, have increments of 5 or 10% of bill based on the quality of service or the food. That way you're being honest and consistent.