Know exactly what you owe
across every W2
Your employers each withhold like they're your only job. They're not. MultiW2 shows the real gap and tells you exactly how to close it.
or try the calculator first — no sign-up needed
Built by a W2 earner who overpaid Social Security for 3 years.
2026 IRS rates
Always current brackets, FICA, and SS wage base
$184,500 SS wage base
Tracked automatically across employers
6 calculators built in
Federal tax, SS overpayment, Medicare, W-4, retirement, quarterly
Built for professionals with 2–10 simultaneous W2 jobs
Multiple jobs. One tax return. Zero visibility.
When you have more than one W2, your taxes get complicated fast. Each employer withholds as if they're your only job. The IRS doesn't care — they add it all up at filing time, and the gap between what was withheld and what you actually owe can be thousands of dollars.
Most people don't find out until April. MultiW2 tells you in real time.
Set up in 2 minutes. Know your tax number in 3.
Add your jobs
Enter your employer name, salary, and pay frequency. 30 seconds per job. You can add up to 10.
Enter your latest pay stub
Copy the YTD totals from your most recent pay stub — gross income, federal withheld, SS withheld, Medicare withheld. That's it. No backfilling 6 months of paychecks.
See your real tax picture
MultiW2 runs 6 calculators across all your jobs: federal tax liability, withholding gap, Social Security overpayment, Medicare, W-4 adjustment, and quarterly estimates. Updated every time you add a new pay stub.
One dashboard. Six tools. Built for multiple W2 jobs.
See the calculator in action
Here's what a 2-job calculation looks like. Two W2 incomes, one combined tax picture. The withholding gap, SS overpayment, and W-4 adjustment — all in one view.
Less than one hour with a tax advisor
Start free. Upgrade when you want exact numbers and the full toolkit.
Not sure yet? Try the calculator free — no account needed.
Your financial data stays yours
What we don't do
No bank connections. No filing. No employer visibility. Your data is row-level-isolated in Supabase and deletable in one click. See our methodology for how calculations work.
Frequently asked questions
W2 tax calculations are accurate to the dollar for all users — free and Pro. The tax engine uses 2026 IRS tax brackets and FICA rates (SS wage base $184,500 at 6.2%), based on CPI-adjusted 2025 published rates. Estimate Tax Liability (which projects future taxes from your pay stubs) shows approximate ±15% ranges for free users and exact projections for Pro users.
Your most recent pay stub for each job. Look for the YTD (year-to-date) section — you'll enter your YTD gross income and YTD federal, Social Security, and Medicare withholding. It takes about 60 seconds per job.
Yes. We never connect to your bank accounts or payroll systems. Your data is stored in encrypted databases with row-level security — only you can access your records. We only store what you type in: salary numbers and withholding amounts.
The scenario modeler supports 1099 income modeling including self-employment tax (15.3% on 92.35% of net income). You can model adding freelance or contract work alongside your W2 jobs to see the full tax impact.
Yes. MultiW2 handles mid-year tax planning: withholding gap tracking, W-4 optimization, quarterly payment sizing, and scenario modeling. Your filing software or CPA handles April. They're complementary, not competing.
No. MultiW2 never connects to any employer system, payroll provider, or benefits portal. All data is entered manually by you, and only you can access your account. Your employers have no way to know you use this tool.
No. MultiW2 is a planning and optimization tool, not tax preparation software. Use it throughout the year to understand your tax picture, then take your year-end prep kit to your accountant or filing software.
IRS safe harbor rules protect you from underpayment penalties. If your total withholding equals at least 100% of last year's tax liability (110% for AGI over $150K), you're penalty-safe — even if you owe money at filing. MultiW2 calculates your safe harbor threshold when you enter your prior year W2, so you know the minimum withholding target to stay penalty-free.
Currently we calculate federal income tax, FICA (Social Security and Medicare), and provide W-4 federal withholding recommendations. Multi-state tax modeling is on our roadmap.
Your data stays accessible in read-only mode. You can still log in and see your saved calculations and job data, but you can't create new calculations, enter W2 data, or access Pro workflows. You can export or delete your data anytime from your dashboard. Resubscribing restores full access immediately.
Your next paycheck is coming.
Do you know what you owe?
Set up in 2 minutes. Free forever for up to 3 jobs.