What Is Back Pay? Definition, Types and How to Calculate It

Back pay is the difference between what an employer was legally required to pay and what they actually paid. It is the remedy for wage theft. Under the FLSA, you can typically recover back pay going two years into the past — three years if the employer's violation was willful. On top of the back wages themselves, courts routinely award liquidated damages equal to 100% of the amount owed.

Common types of back pay claims

Unpaid overtime is the most frequent back pay claim: an employer failed to pay 1.5× the regular rate for hours over 40, or paid overtime on the base wage but excluded a bonus that should have been included in the regular rate. Minimum wage shortfalls are next, particularly for tipped workers whose cash wage plus tips fell short of the applicable minimum.

Back pay also arises from off-the-clock work (mandatory meetings, pre-shift tasks), unlawful deductions from paychecks, failure to pay for all hours in a split shift, and unpaid final wages when employment ends.

How to calculate back pay

For overtime back pay: identify the correct regular rate of pay for each affected week, count the overtime hours the employer either underpaid or didn't pay at all, and multiply by the underpayment rate (0.5× for hours paid at straight time instead of 1.5×, or 1.5× for hours not paid at all). Sum that across every week in the claim period.

The back-pay calculator does this arithmetic automatically. Enter your hourly rate, actual hours worked, and hours the employer paid. The output is a week-by-week underpayment figure you can take directly to the WHD or an employment attorney.

Liquidated damages: the doubling rule

Under 29 U.S.C. § 216(b), plaintiffs in a successful FLSA lawsuit are entitled to liquidated damages equal to the full amount of back wages owed. If you are owed $5,000 in unpaid overtime, the total recovery is typically $10,000. Employers can avoid liquidated damages only if they prove they acted in good faith and had a reasonable belief their pay practice was lawful — a high bar that few employers meet.

State law may give you more

State wage laws often allow longer lookback windows and higher penalties. California permits four-year lookbacks for certain claims and adds waiting-time penalties for late final pay. New York allows six years and 100% liquidated damages. Illinois allows five years. If both federal and state claims apply, you recover under whichever theory produces the better outcome — you are not limited to the federal minimums.