A paycheck that is higher or lower than expected is almost always explainable. The key is knowing where to look on your pay stub and which changes could have caused the shift.
Most Common Reasons Your Paycheck Is Different
Your Hours Changed
The most common reason for hourly employees:
| Situation | Effect on Paycheck |
|---|---|
| Worked extra hours | Higher |
| Fewer hours than usual | Lower |
| Included overtime | Higher (1.5x rate) |
| Used unpaid time off | Lower |
Even salaried workers can have pay changes if they have variable components like commissions, shift differentials, or on-call pay.
A Benefit Deduction Changed
| Trigger | When It Happens |
|---|---|
| Annual open enrollment | January (or your plan year start) |
| Added a dependent | After a qualifying life event |
| Dropped a benefit | After a qualifying life event |
| Premium increase | When the plan year renews |
Health insurance premiums often increase in January — many workers notice their first paycheck of the year is smaller for this reason.
Your Tax Withholding Changed
| Cause | Result |
|---|---|
| Filed a new W-4 | Withholding increased or decreased |
| Got married or divorced | May affect withholding |
| Added a dependent | Can reduce withholding |
| Large bonus on previous check | IRS may have under-withheld previously |
You Received a Bonus or Commission
Bonuses are typically taxed at a 22% supplemental withholding rate, which can look different on your stub than regular paycheck taxes.
You Hit the Social Security Wage Cap
Once you earn over $168,600 in a year, Social Security withholding (6.2%) stops. Your paycheck grows by roughly that percentage from that point through December.
One-Time Deductions
| One-Time Deduction | What It Is |
|---|---|
| Wage garnishment (new) | Court-ordered deduction started |
| Repayment deduction | You repaid an advance or overpayment |
| Retroactive benefit deduction | Enrollment delay catch-up |
| Union dues start | New union enrollment |
A Raise Took Effect
A raise does not increase take-home pay dollar for dollar because higher income can push you into a higher tax bracket.
| Raise Amount | Approximate Net Pay Increase |
|---|---|
| $2,000/year raise | +$115-$135/paycheck (biweekly) |
| $5,000/year raise | +$265-$315/paycheck (biweekly) |
| $10,000/year raise | +$500-$620/paycheck (biweekly) |
Why Your First Paycheck Is Almost Always Small
| Reason | Explanation |
|---|---|
| Partial pay period | You may have started mid-period |
| W-4 not processed | System defaults to $0 allowances = maximum tax |
| Benefits started | Deductions kick in immediately |
| One-time new-hire fees | Some companies deduct ID badges, uniforms, etc. |
How to Diagnose a Paycheck Discrepancy
Step 1: Review Your Pay Stub
Compare these items to what you expect:
| Item to Check | Where to Look |
|---|---|
| Gross pay | Should match hours × rate or salary ÷ periods |
| Federal tax withheld | Use IRS withholding calculator to verify |
| Benefit deductions | Should match your enrollment confirmation |
| Any new deductions | Look for unfamiliar line items |
Step 2: Compare to Previous Stub
Pull your previous paycheck and do a side-by-side comparison. Identify every line that changed.
Step 3: Contact Payroll
Bring your pay stub comparison to HR or payroll. Ask:
- “Can you confirm my pay rate and hours?”
- “Why did [specific deduction] change?”
- “Is this a permanent change or one-time?”
Payroll is required to correct errors and may retroactively fix underpayments.
Changes That Affect Every Check Going Forward
| Change | Permanent? |
|---|---|
| Benefit election | Until next open enrollment |
| New W-4 | Until you file another one |
| Raise | Yes |
| Garnishment | Until debt is paid off |
| Social Security cap | Resets every January 1 |
Related: Understanding Paycheck Deductions | Gross vs. Net Pay Explained | Why Is So Much Taken Out of My Paycheck