Under the Fair Labor Standards Act, you are required to keep such records for at least three years from time of creation. However, we recommend that personnel records, including payroll records and timecards, be kept for seven years from the date the record is made or the date of termination, whichever is longer. That way, if you are subject to an IRS audit (which could go back seven years), you have this supporting documentation available upon request.
If you’re currently using a paper timekeeping system and you don’t want to store that much paper around the office for seven years, you can scan paper documents for electronic storage. Just make sure you have a reliable and secure method for storing this sensitive information and are able to access it as needed.