How to Calculate Back Pay for Unpaid Overtime

Understanding Overtime Back Pay

Under federal law (FLSA) and most state laws, non-exempt employees must receive 1.5x their regular hourly rate (time and a half) for hours worked over 40 in a workweek. If you worked overtime but weren't paid correctly, you're owed the difference between what you were paid and what you should have been paid.

The Basic Formula

The formula for calculating overtime back pay is straightforward:

Step-by-Step Calculation

1. Determine your regular hourly wage: This is your base rate before overtime
2. Identify unpaid overtime hours: Hours worked over 40 per week that weren't paid at 1.5x
3. Calculate the overtime rate: Regular wage × 1.5
4. Multiply by unpaid hours: Overtime rate × unpaid overtime hours
5. Multiply by pay periods: Result × number of weeks/pay periods affected

Example Calculations

Example 1: Simple Unpaid Overtime

You earn $20/hour and worked 45 hours in a week, but were only paid for 40 hours at regular rate. You're owed 5 hours of overtime pay:

Example 2: Multiple Weeks

You earn $25/hour and worked 45 hours per week for 4 weeks, but were only paid for 40 hours each week:

Example 3: Underpaid Overtime

You earn $20/hour and worked 45 hours. Your employer paid you $25/hour for the 5 overtime hours, but you should have received $30/hour (1.5x):

Special Cases

Daily Overtime (California, Nevada, etc.)

Some states require overtime for hours over 8 per day, not just 40 per week. For example, in California:

• Hours 1-8: Regular rate
• Hours 9-12: 1.5x (time and a half)
• Hours over 12: 2x (double time)
• Hours over 40 per week: 1.5x

Calculate daily overtime separately from weekly overtime, and use the higher rate.

Misclassification

If you were misclassified as exempt from overtime but should have been non-exempt, you're owed overtime for all hours over 40 per week. This can result in significant back pay, especially if you regularly worked 50-60+ hours per week.

Off-the-Clock Work

If you were required to work before or after your shift without pay, those hours count toward your weekly total. If they push you over 40 hours, you're owed overtime for those hours.

Adding Interest and Penalties

In addition to the unpaid overtime itself, you may be entitled to:

• Interest: Some states have statutory interest rates (e.g., California 10%, Massachusetts 12%)
• Liquidated Damages: Equal to unpaid wages, effectively doubling what you're owed
• Penalties: Additional compensation for willful violations

Use our state-specific calculators to see what additional compensation may apply in your state.

Documenting Your Claim

To successfully claim overtime back pay, document:

• Hours worked each day and week
• Pay stubs showing what you were paid
• Timecards or time records
• Communications with your employer about hours
• Any evidence of off-the-clock work