Amazon is hiring 250,000 people across its U.S. fulfillment and transportation operations this holiday season, and every seasonal role pays at least $18 an hour. Twenty hours a week from mid-October through Christmas works out to roughly $3,600. If you already hold a full-time job, about $742 of that money is not yours, and your seasonal employer will withhold almost none of it. That gap is not a mistake. Second job tax withholding is designed to produce it.
I have watched friends work ten weeks of evenings at a warehouse and then get genuinely upset in April, when the refund they had already mentally spent came back four figures light. The money was never missing. It was sitting in a payroll system that had no idea the other job existed.
Both of your employers think they are the only one
There is no clearinghouse that tells your warehouse job about your day job. Payroll software calculates withholding from the wages in front of it and nothing else, so your main employer hands you the full standard deduction and starts you at the bottom of the rate schedule, and your seasonal employer does the identical thing four hours later on the same evening.
For 2026, the standard deduction for a single filer is $16,100, and the rates start at 10% on the first $12,400 of taxable income, then 12% up to $50,400, then 22% up to $105,700, according to the Tax Foundation’s 2026 bracket tables. (The Congressional Research Service keeps the full historical series in report RL34498 if you want to see how the thresholds have moved.) When two employers each apply that structure independently, $16,100 of your income gets sheltered twice and the bottom 10% band gets used twice. You only get one of each when you actually file.
Payroll taxes behave differently, which is worth knowing so you do not go looking for a problem that is not there. Social Security takes 6.2% and Medicare takes 1.45% from every dollar at both jobs, with no deduction and no brackets to double up. Those come out correctly. Federal income tax is the one that goes sideways.
Second job tax withholding annualizes a paycheck you will only get five times
Here is the mechanism that does the damage. Payroll withholding never looks at your year. It looks at one paycheck and asks what your tax would be if you earned that amount every pay period, all year long.
Say the seasonal job pays $720 every two weeks, which is 40 hours at $18. The payroll system annualizes that to $18,720. Subtract the $16,100 standard deduction and you are left with $2,620 of taxable income, taxed at 10%, which is $262 for a full year. Spread over 26 pay periods, the withholding tables land somewhere around $10 a check. Across five checks, you will see roughly $50 withheld.
Now the real math. Suppose your main job pays $72,000. Take out the standard deduction and your taxable income is $55,900, which means your last dollars are being taxed at 22%. The $3,600 from the warehouse stacks on top of that, and because $59,500 is still well short of the $105,700 line, every dollar of it is a 22% dollar. That is $792 of federal tax.
So: $792 owed, about $50 withheld, $742 short. You earned that money in November and you find out about the shortfall in April, which is the worst possible sequencing for a household that just spent December.
The multiple jobs checkbox is the wrong tool for a ten-week job
Search this problem and you will get the same answer from every result on the first page: check the box in Step 2(c) of your W-4. The box is real and it does something. It is also calibrated for a situation you are not in.
Checking 2(c) cuts the standard deduction and every bracket width in half for that job, on the theory that each of your two jobs pays about half your income. The form says as much: it is accurate when the two jobs pay similar amounts. A $72,000 job and a $3,600 job are not similar amounts.
Run it. Check the box on both W-4s, as the instructions allow when you hold exactly two jobs, and your main job’s withholding gets computed against a halved $8,050 deduction and halved brackets. That pushes its annual withholding to about $11,647. The seasonal job, under the same treatment, withholds about $222. Together that is $11,869 against a true combined tax bill of $7,802. You have just handed the government an extra $4,000 for the year, interest free, to solve a $742 problem.
The tool that actually fits is Step 4(c), the line for extra withholding per pay period. Divide your expected shortfall by the number of paychecks left in the year and put that number on the line. If the seasonal job runs five pay periods, $742 divided by five is about $149 a check. You can also put the whole thing on your main job’s W-4 instead, spread across whatever paychecks remain, which is easier if the seasonal employer’s onboarding portal is the kind that fights you.
Extra withholding in October cures a shortfall from January
Under Internal Revenue Code Section 6654(g), tax withheld from wages is treated as paid evenly across the whole year, no matter which month it actually came out. An extra $742 withheld in November is treated as though roughly $185 of it was paid in each quarter, including the quarters that already closed. So the underpayment penalty machinery, which otherwise charges you per period, gets cured retroactively.
Estimated tax payments do not work this way. Those are credited when you send them, so a December check to the IRS leaves the first three quarters underpaid and the penalty intact. If you are going to fix an underpayment late in the year, fix it through a paycheck rather than a payment.
The penalty rules themselves give you room. Section 6654 generally leaves you alone if your payments for the year reach 90% of what you end up owing, or 100% of what you owed last year (110% if your adjusted gross income topped $150,000). For most people picking up a holiday job, matching last year’s total tax is the easier of the two targets to hit, because you can look the number up on the return you already filed.
If the seasonal job is your only job, you have the opposite problem
Flip the situation and the annualizing works against you. Someone whose only 2026 income is a ten-week warehouse stint gets treated by the payroll system as an $18,720-a-year earner, so tax comes out of every check even though the actual annual income is $3,600 and the actual tax is zero. You get it all back, eventually, as a refund in the spring.
There is a fix most people never hear about. The IRS allows a part-year employment withholding method for workers who will be employed no more than 245 days across the calendar year, and an employee can ask their employer in writing to use it. Instead of annualizing, it computes withholding against your real year-to-date wages. The American Payroll Association flagged it again when the 2026 version of Publication 15-T came out in December 2025. Not every payroll department will do it, and small employers often decline. It costs one email to ask.
What to do this week
Open the job posting and multiply the hourly rate by the hours you actually expect to work before December 31. If you earn between about $55,000 and $85,000 at your main job, take 22% of that number, because that is the bracket the extra income will land in. Divide by the paychecks you have left. Put the answer on line 4(c) of a W-4 at whichever job has the friendlier portal, and leave the Step 2 checkbox alone.
Ten minutes, and the $742 stops being a surprise. Second job tax withholding is one of the few money problems where the calendar is still on your side in late September, and stops being on your side around the middle of December. If you are already thinking about the fourth quarter, it pairs well with the fact that October 2026 is a three-paycheck month for millions of workers, and with getting your holiday sinking fund full by November 1 rather than by Christmas Eve.
