Retroactive Pay Calculator
Calculate the retroactive pay you're owed when a raise takes effect later than its effective date. Supports hourly and salaried workers, with federal supplemental tax withholding and FICA estimates.
Pay Type
Pay Frequency
Old Hourly Rate
New Hourly Rate
Hours Worked at Old Rate
Old Annual Salary
New Annual Salary
Pay Periods Affected
Disclaimer: Estimates only. The flat 22% federal rate is one of two IRS supplemental-wage methods (the other is aggregate); your employer's actual withholding may differ. Amounts above $1M are withheld at 37%. State withholding varies and is not included.
Track Every Hour, Catch Every Raise
The app logs your shifts and pay rates automatically, so you have the receipts when a retro adjustment goes missing.
How Retroactive Pay Works
Retroactive pay (or "retro pay") is the wage difference you're owed when a raise was approved with an earlier effective date but didn't hit your paycheck on time. Your employer agreed you'd be making the new rate starting on, say, the first of the month, but payroll kept paying the old rate for a few cycles. Retro pay is the catch-up.
This is different from back pay, which covers wages that were never paid at all (unpaid hours, missed overtime, minimum wage violations). Retro pay is just an accounting correction. Back pay usually involves a wage-law violation and can come with FLSA liquidated damages. Retro is bookkeeping catching up to a promise that was already made.
The IRS treats retro pay as "supplemental wages." That label matters because it changes how federal income tax is withheld on the catch-up check.
Hourly Retro Pay: Step by Step
The formula for an hourly worker is simple:
(New rate − Old rate) × Hours worked at the old rate during the retro period = Gross retro pay
Example: your hourly rate went from $18 to $20 effective the start of last month, but payroll didn't update until this paycheck. You worked 160 hours at the old rate. Your retro pay is ($20 − $18) × 160 = $320 gross.
Salary Retro Pay: Step by Step
For salaried workers, divide each annual salary by the number of pay periods per year, take the per-period difference, and multiply by how many periods were affected.
Example: your salary went from $60,000 to $65,000 on a biweekly schedule (26 periods/year), and two periods were paid at the old rate. The per-period shortfall is $5,000 / 26 = $192.31. Total retro pay = $192.31 × 2 = $384.62 gross.
Tax Withholding on Retro Pay
Retro pay is "supplemental wages" under IRS rules. When paid separately from your regular wages, employers most often use the flat-rate method: 22% federal income tax withholding on amounts up to $1 million (37% above that). This is per IRS Publication 15 (Circular E), Section 7. The alternative is the aggregate method, where retro pay is combined with regular wages and withheld at your normal rate.
FICA always applies: Social Security at 6.2% (on wages up to $176,100 in 2026) and Medicare at 1.45%, for a combined 7.65%. Workers earning above $200,000 also owe an additional 0.9% Medicare tax (not included in this calculator).
State income tax withholding varies. Some states have their own supplemental rates; others use regular tables. Check with your payroll department if state withholding looks off.
Hourly Retro Pay Quick Reference
| Raise per Hour | 40 hrs | 80 hrs | 160 hrs | 320 hrs | 480 hrs |
|---|---|---|---|---|---|
| $0.50 | $20 | $40 | $80 | $160 | $240 |
| $1.00 | $40 | $80 | $160 | $320 | $480 |
| $1.50 | $60 | $120 | $240 | $480 | $720 |
| $2.00 | $80 | $160 | $320 | $640 | $960 |
| $2.50 | $100 | $200 | $400 | $800 | $1,200 |
| $3.00 | $120 | $240 | $480 | $960 | $1,440 |
| $4.00 | $160 | $320 | $640 | $1,280 | $1,920 |
| $5.00 | $200 | $400 | $800 | $1,600 | $2,400 |
| $7.50 | $300 | $600 | $1,200 | $2,400 | $3,600 |
| $10.00 | $400 | $800 | $1,600 | $3,200 | $4,800 |
Salary Retro Pay Quick Reference (Biweekly, 26 Periods)
| Annual Raise | Per-Period Shortfall | 2 periods | 4 periods | 6 periods | 12 periods |
|---|---|---|---|---|---|
| $1,000 | $38.46 | $76.92 | $153.85 | $230.77 | $461.54 |
| $2,500 | $96.15 | $192.31 | $384.62 | $576.92 | $1,153.85 |
| $5,000 | $192.31 | $384.62 | $769.23 | $1,153.85 | $2,307.69 |
| $7,500 | $288.46 | $576.92 | $1,153.85 | $1,730.77 | $3,461.54 |
| $10,000 | $384.62 | $769.23 | $1,538.46 | $2,307.69 | $4,615.38 |
| $15,000 | $576.92 | $1,153.85 | $2,307.69 | $3,461.54 | $6,923.08 |
Net After Tax (22% Federal + 7.65% FICA)
| Gross Retro | Federal (22%) | FICA (7.65%) | Estimated Net |
|---|---|---|---|
| $320 | $70.40 | $24.48 | $225.12 |
| $500 | $110.00 | $38.25 | $351.75 |
| $1,000 | $220.00 | $76.50 | $703.50 |
| $2,500 | $550.00 | $191.25 | $1,758.75 |
| $5,000 | $1,100.00 | $382.50 | $3,517.50 |
Don't Forget Overtime
Under 29 CFR § 778.303, a retroactive raise also retroactively increases your "regular rate of pay" for FLSA purposes. That means every overtime hour you worked during the retro period must be recomputed at 1.5× the new rate, not the old one. For overtime-heavy retro periods, work the OT premium through the Regular Rate of Pay Calculator too.
What to Do If Your Employer Won't Pay
- Document the approval. Save offer letters, emails, or HR records confirming the effective date of the raise.
- Raise it with payroll. Most retro pay issues are honest payroll lag and get fixed the next cycle.
- Escalate to HR or management if payroll won't act. Put your request in writing.
- File a complaint with the DOL Wage and Hour Division if it's still unresolved. There's no specific federal deadline for retro pay, but the FLSA expects timely payment.
- Watch the FLSA clock. If the unpaid amount crosses into back-pay territory, the statute of limitations is 2 years (3 for willful violations).
Retro Pay vs Back Pay at a Glance
| Feature | Retro Pay | Back Pay |
|---|---|---|
| Trigger | Raise applied late | Wages never paid |
| Legal nature | Accounting correction | Often a wage-law violation |
| Liquidated damages | No | Yes, under FLSA (2x) |
| Tax treatment | Supplemental wages (22%) | Supplemental wages (22%) |
| Typical remedy | Next payroll catch-up | DOL claim or lawsuit |
Sources: IRS Publication 15 (Circular E), Section 7, IRS Publication 15-T, 29 CFR § 778.303, U.S. DOL Back Pay, QuickBooks, Paycor, Salary.com
Frequently Asked Questions
Common questions about retroactive pay calculator
What is retroactive pay?
Retro pay is the difference between what you were paid and what you should have been paid after a rate change with an earlier effective date. It's the catch-up check when a raise was approved for one date but only landed on your paycheck a cycle or two later.
How is retro pay different from back pay?
Back pay covers wages owed for work that was never paid at all, and it usually involves a wage-law violation. Retro pay is a correction for underpayment when wages were paid, just at the wrong rate. Retro pay is an accounting fix; back pay is a legal claim.
How is retro pay taxed?
The IRS treats retro pay as supplemental wages. When paid separately from your regular wages, employers commonly withhold federal income tax at the flat 22% supplemental rate (37% above $1M). Social Security and Medicare (FICA) apply normally at 7.65% combined. State withholding varies.
When is retro pay required by law?
Whenever an employer agrees to a raise with an effective date earlier than the date payroll caught up, or when a payroll error underpaid you. The FLSA requires wages to be paid on time, and the DOL generally expects corrections by the next regular payday.
How do I calculate retro pay for an hourly employee?
Multiply the per-hour raise (new rate minus old rate) by the number of hours you worked at the old rate during the retro period. Example: a $2/hour raise applied to 160 hours = $320 gross retro pay.
How do I calculate retro pay for a salaried employee?
Divide each annual salary by the number of pay periods per year (52 weekly, 26 biweekly, 24 semimonthly, 12 monthly), take the difference per period, then multiply by the number of pay periods affected. Example: $60K to $65K biweekly = ($5,000 / 26) = $192.31/period.
How long does an employer have to pay retroactive pay?
There's no specific federal deadline, but the DOL expects corrections by the next regular payday. State payday laws may impose tighter windows. If your employer drags its feet, document the approval and raise it in writing.
Does retro pay affect overtime calculations?
Yes. Under 29 CFR § 778.303, a retroactive raise also retroactively increases your regular rate of pay, so every overtime hour worked during the retro period has to be recomputed at 1.5× the new rate, not the old one. For overtime-heavy retro periods, the OT premium needs to be redone too.