Tipster: Tip calculator for fast meal math

Puzzled by percentages? Ilium Software's Tipster for Palm and Windows Mobile serves up the correct tip amount and splits your bill among fellow eaters.


For consistent 15 percent tipsters living in municipalities with a 7.5 percent dining tax, generating the perfect 15 percent tip is as simple as doubling the tax. If that's not you, Oh Arithmetic-Challenged One, you've got a bum deal. (See below for a quick computational technique.)

It's for this set, and for diners who frequently split a bill, that Ilium Software developed Tipster. The free, simple app for Palm, Windows Mobile smartphone and Pocket PC hurriedly computes your tax and total.

Tipster calculates tax in 5 percent increments up to 30 percent, and can evenly split the amount owed among diners (up to ten,) tip included. Working out how much four people should pay on an $86.52 bill with a 20 percent tip becomes instant and headache-free. Just don't try anything funny, like tipping 18 percent.

Math-addled? An easy way to compute 15 percent tip.
1.) Look at the total bill: $20.51 (or euros, pesos, etc.)
2.) Take the first three digits (in bills under $1,000), and mentally add a decimal point after the first digit.*: $20.51 --> $2.05. That's 10 percent. Let's round down to $2.00.
3.) Halve that to get 5 percent: $1.00.
4.) Add both calculations to reach 15 percent: $3.00

*To calculate 10 percent in bills under $10, take the first two digits and make them cents: $7.50 --> 75 cents. To calculate 10 percent in bills over $1,000, add the decimal point after the first three digits: $1,150 --> $115.

About Jessica Dolcourt

Jessica Dolcourt reviews smartphones and cell phones, covers handset news, and pens the monthly column Smartphones Unlocked. A senior editor, she started at CNET in 2006 and spent four years reviewing mobile and desktop software before taking on devices.