W-4 with Two Jobs or a Side Hustle
Multiple income sources change your W-4 strategy. Here's exactly how to handle it.
By Reba Donaldson · Last reviewed: April 2026
Why two jobs create a withholding problem
Each employer withholds taxes based only on the income you earn from them — they have no idea about your other job. If both jobs pay $40,000, each employer withholds as if $40,000 is your total income. But your combined income is $80,000, which is taxed at higher rates. The result: both employers underwithheld, and you owe money in April.
Two W-4 jobs: Step 2 is your fix
You need to complete Step 2 on at least one of your W-4s (ideally both). The three options:
Option A — IRS Estimator: Most accurate. Go to irs.gov/W4app, enter both incomes, and apply the calculated extra withholding to Step 4(c).
Option B — Worksheet: Complete the Multiple Jobs Worksheet (page 3 of W-4 instructions). Slightly more manual but doesn't require the IRS website.
Option C — Check the box: Simplest. Both employers withhold at the higher Single rate. You'll likely overwithhold slightly but you won't underpay.
W-4 with freelance or 1099 side income
Freelance income doesn't have an employer to withhold taxes. You have two options:
Option 1 — Increase W-4 withholding: On your day job W-4, enter the estimated annual tax on your freelance income in Step 4(a) (other income). Your employer will withhold extra from each paycheck to cover it. Simple — no quarterly estimated tax payments needed.
Option 2 — Pay quarterly estimated taxes: Make separate IRS quarterly payments on your freelance income. More work, but more flexible if your side income is irregular. If your side hustle earns over $1,000 in net profit, you likely need to do this or Option 1.
Our recommendation: if your side income is predictable, use Option 1 — increase your day job withholding via Step 4(a). It's cleaner and removes the quarterly deadline pressure.
How much extra to withhold
A rough rule: add 25–30% of your expected net freelance income to Step 4(a). This covers income tax plus self-employment tax for most people. Our W-4 calculator does the exact math based on your specific situation.