TL;DR
- ✅ Step 4(c) = extra tax withheld per paycheck, on top of normal withholding
- ✅ Formula: (amount you want covered) ÷ (paychecks left this year)
- ✅ It stays in effect until you submit a new W-4, so revisit it next January
- ✅ Use it to stop owing in April, to get a bigger refund, or to cover side income
The formula
Decide how many extra dollars you want withheld for the year, then divide by the number of paychecks you have left. Round up.
Step 4(c) = extra tax needed ÷ pay periods remaining
Pay periods remaining is not 52, 26 or 12 unless you are doing this in January. Count the paychecks left including the one that will include your new W-4, since employers usually need a pay cycle or two to put it into effect.
Worked examples
I owed $1,800 last April and my situation has not changed
Biweekly, 18 pay periods left: $1,800 ÷ 18 = $100. Enter $100 in Step 4(c).
I want a $1,200 larger refund
Monthly pay. In January with 12 paychecks left: $1,200 ÷ 12 = $100. In October with only 3 left: $1,200 ÷ 3 = $400. The same goal costs four times as much per paycheck when you start late.
I earn $15,000 a year freelancing on the side
Estimate the tax: about 25 to 30 percent of net profit including self-employment tax, roughly $4,000. Weekly with 20 weeks left: $4,000 ÷ 20 = $200 per week in Step 4(c) on the W-2 job.
The Multiple Jobs Worksheet says $2,640 a year
Biweekly, 26 periods: $2,640 ÷ 26 = $101.54, so enter $102 on the higher-paying job’s W-4.
Let the calculator pick your Step 4(c) — free
Enter your pay and situation to see what to write on Step 4(c) and the rest of the form.
Open the W-4 Calculator →Step 4(c) vs. Step 2
Step 2 corrects the tax tables for a second job or a working spouse. Step 4(c) is a plain extra amount. If you have more than one income, start with Step 2; the IRS estimator and the Multiple Jobs Worksheet then give you a 4(c) figure to enter on the highest-paying job. For a side hustle with no second W-2, 4(c) is the right place for the whole adjustment. See W-4 Step 2 explained and W-4 for side income.
How much do I actually need to withhold?
To avoid an underpayment penalty, your withholding plus estimated payments should reach the lesser of 90 percent of this year’s tax or 100 percent of last year’s (110 percent if your adjusted gross income was above $150,000). Anything beyond that is a loan to the IRS in exchange for a refund. Run the numbers in our safe harbor guide and decide whether you prefer a refund or bigger paychecks.
⚠️ Re-check when your pay changes
A flat amount does not scale. After a raise, a bonus year or a new job, rework the number. See refund vs. adjusting your W-4 and how often you can change your W-4.
Frequently asked questions
What do I put on Step 4(c) of the W-4?
Enter the extra dollar amount you want withheld from each paycheck, in addition to the normal withholding. To size it, take the amount you expect to owe or want as a refund and divide it by the number of pay periods left in the year.
Is the Step 4(c) amount per paycheck or per year?
Per paycheck. Your employer withholds that dollar amount on every pay period until you submit a new W-4, so a weekly employee and a monthly employee need very different numbers for the same yearly target.
Should I use Step 2 or Step 4(c) for a second job?
Use Step 2 to correct for the second job’s effect on brackets. Step 4(c) is a flat adjustment on top. The Multiple Jobs Worksheet and the IRS estimator actually produce a Step 4(c) number for you, so the two are often used together.
Can I use Step 4(c) to avoid an underpayment penalty?
Yes. Withholding is generally treated as paid evenly through the year even if you raise it late, so increasing 4(c) with a few months left can still cover a shortfall. Check the safe harbor thresholds to see how much you need.
Is there a maximum amount for Step 4(c)?
No maximum is stated on the form, but your employer cannot withhold more than your net pay, and some payroll systems cap the percentage. If you need a very large amount, split it across a second employer or make an estimated payment.
Key terms in this article
Related guides
W-4 Step 4 Explained: Other Income, Deductions, and Extra Withholding (2026)
Step 4 is how you fine-tune for side income, itemized deductions, and extra withholding. Most people skip it — here's when you shouldn't.
IRS Safe Harbor: How to Avoid Underpayment Penalties on Your W-4 (2026)
The IRS charges penalties when you underpay by too much. The safe harbor rules let you optimize your W-4 aggressively without triggering them.
W-4 for Freelancers, 1099 and Side Gig Income (2026 Guide)
Side income has no withholding, so it shows up as a surprise tax bill. Cover income tax and self-employment tax through Step 4c or quarterly estimates, with worked examples and 2026 due dates.
Tax Refund vs. Adjusting Your W-4: How to Keep More Money Every Paycheck
The average refund is $3,100 — that's money that was yours all year. Here's how to decide whether a big refund is working for you or against you.
How to Get a Bigger Tax Refund With Your W-4 (2026)
Two ways to a bigger refund: withhold more during the year with Step 4(c), or owe less at filing. How each works.
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