That $20 your regular left on a $60 tab felt like a gift.
The IRS sees it as wages, and it has been treating it that way for decades.
If you work for tips, the money doesn't stop being taxable just because it arrived in cash, through an app, or in a jar by the register.
The rule is simpler than most people assume.
Tips are taxable income whether you're paid in cash, by card, through a payment app, or split with coworkers through a tip pool.
The only tips that escape federal income tax are the ones you never receive.
Employers are supposed to collect income tax, Social Security, and Medicare on reported tips, and you're supposed to report them.
Yet a lot of tipped workers quietly don't.
The IRS estimates that billions in tip income goes unreported every year, which is why restaurants, salons, and delivery platforms have gotten more aggressive about tracking it.
Cash tips are the gray zone, and that gray zone is shrinking.
The mechanics matter because they hit your paycheck in two places.
First, reported tips count as wages, so they can push you into a higher tax bracket and raise your withholding.
Second, if your reported tips are under $20 in a month, your employer generally doesn't have to withhold Social Security and Medicare on them—but you still owe that money when you file.
There's also a form you should know about.
If you receive $20 or more in tips in any month, you're supposed to report them to your employer using Form 4070 by the 10th of the following month.
Your employer then withholds taxes based on that report.
Skip it, and you may owe a lump sum at tax time plus potential penalties.
Say you earn $15 an hour plus $200 a week in cash tips.
Your employer withholds on the $15, but not necessarily on the tips if you never report them.
Come April, that unreported $10,400 becomes taxable income, and you could owe thousands in back taxes, interest, and a penalty on top.
This is why tip reporting has become a political flashpoint.
Several states and cities have moved to eliminate the tipped minimum wage, which changes the calculus for workers who rely on tips.
Meanwhile, the IRS has run compliance programs aimed at industries where cash tips are common, and some employers now use apps that log every tip automatically.
If you're a tipped worker, the practical move is boring but effective.
Keep a daily log of cash tips—a notes app works.
Report them to your employer monthly if you hit the threshold.
Set aside roughly 15 to 30 percent of tip income depending on your bracket and state, so April doesn't ambush you.
And if you're behind on reporting, talk to a tax professional before the IRS talks to you.
One more wrinkle: tip pools and service charges are not the same thing.
A mandatory service charge added to a bill is generally wages, not a tip, and it's taxable to the employer's payroll either way.
A voluntary tip left by a customer is a tip.
That distinction matters when you're trying to figure out what you actually owe.
The short version: cash feels invisible, but it isn't.
The IRS has a form, employers have software, and payment apps have receipts.
Treating tips as untaxed bonus money is a gamble that gets more expensive every year.
The honest takeaway is that tip income has always been taxable—what's changed is how easy it is to track.
Workers who get ahead of it sleep better in April.
Final Thoughts
Workers who don't often find out the hard way that the government keeps better records than they do.