If you’re an employee who earns tips, it’s important to keep track of all the tips you received. Keep a daily record of all tips (cash and noncash) you receive and how much of those tips you reported to your employer. The IRS has Form 4070A that can help you calculate your daily tips for each month. When calculating your tips for the day, don’t include gratuity tips (tips charged for large parties).
Keep in mind that unreported tips are still considered income to the IRS and it’s subject to Social Security and Medicare taxes, so you must report this income on your tax return by filing Form 4137, Social Security and Medicare tax on Unreported Tip Income.