A gross-up answers the inverse of a take-home calculator: you already know the deposit you want, and you need the gross that survives federal withholding and FICA. Employers use it for relocation packages, taxable reimbursements, and offers quoted as a net number.
Single, biweekly (26), no traditional 401(k), W-4 Step 2 unchecked: a $1,500 target net requires $1,811.88 gross. Federal income tax on that check is $173.27. Employee FICA is $138.61. The deposit lands at $1,500.00.
More United States paycheck, FICA, 401(k) and tax tools live on the United States calculators hub.
The search is a binary search on the paycheck take-home engine (IRS Publication 15-T + Topic 751). It is not a Form 1040 bill. State and local tax are out. This is an estimate, not tax advice.
Direct answer: $1,500 in the bank
- Guess a gross, run take-home, compare to $1,500
- Raise the guess if the net is short; lower it if the net is fat
- Stop at the nearest cent: $1,811.88
The $2,000 biweekly default on the take-home page (net $1,651.15) round-trips: gross-up($1,651.15) recovers $2,000.00.
find G such that take-home(G) = target net
take-home(G) = G − traditional 401(k) − other pre-tax − Pub 15-T FIT − FICA
Checks you can re-run
| Setup (single, biweekly) | Target net | Required gross |
|---|---|---|
| Default hero | $1,500.00 | $1,811.88 |
| W-4 Step 2 checked | $1,500.00 | $1,890.82 |
| 10% traditional 401(k) | $1,500.00 | $2,034.71 |
| Step 3 credits $2,000/yr | $1,500.00 | $1,716.14 |
| Step 4(c) extra $50 | $1,500.00 | $1,874.10 |
| Round-trip from $2,000 gross | $1,651.15 | $2,000.00 |
Step 2 uses the two-jobs schedule, so the same net needs more gross. A traditional 401(k) comes out of gross before FIT but not before FICA, so the required gross jumps again. Extra dollars on Step 4(c) are a flat add to withholding; the search has to cover them too.
What this is not
- Not a bonus. Separately identified supplemental wages often use the 22% flat rate. See bonus tax.
- Not employer cost. The extra 7.65% match plus FUTA sits on the company side: employer payroll cost.
- Not 50-state withholding. A Texas net and a California net can share this federal gross and still differ.
It is the gross wages for one biweekly check that produce $1,500 net under this federal model. Annualize only if every check looks like this one. State tax, benefits, and a different W-4 will move it.
Yes, for a traditional deferral. Ten percent on the $1,500 target raises required gross from $1,811.88 to $2,034.71. Roth deferrals are after-tax and are not in this engine.
No. Contractors do not run Pub 15-T. Use self-employment take-home and estimated tax safe harbor.