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Vestgap

Next 1040-ES · September 15, 2026

The gap at vest.

RSUs were withheld at 22%. Copy the 1040-ES for September 15, 2026, or extra W-4 Step 4(c) on remaining checks. One path. A CPA still signs.

Bay Area IC sample still due $34,925 · then split on the desk

Form

$17,463

This year’s picture

W-2 plus vests. No bank login.

Slips are free. One letter on this device, then $49. 1 letter left.

To pay

Live

Form 1040-ES

Due September 15, 2026

$17,463

1 of 2 remaining installments of $34,925 still due.

IRS Direct Pay

Alt · W-4 Step 4(c)

Every 2 wks · ~9 checks

$3,881

Only if you skip the voucher.

Pay $17,463 on September 15, or add $3,881 to W-4 Step 4(c) on remaining checks — not both unless split.

Still due $34,925 after 22% supplemental. Pick 1040-ES or W-4 extra, not both.

Still due
$34,925
Federal gap
$32,500
State gap
$175
Marginal federal
35%

110% safe harbor on last year’s tax: $101,200. 2 installments left this cycle. Extra per remaining check follows the pay cadence you picked.

Flags

  • Federal supplemental withholding on RSUs is 22% (Pub 15), not the 35% marginal bracket on this picture.
  • If nothing else is withheld, about $17,463 is the September 15 slice of $34,925 still due.
  • 110% safe harbor on last year’s tax is $101,200. Hitting it avoids the underpayment penalty even if April is still large.
  • California residency and equity sourcing are not in this figure. Do not treat a move as automatic.

This week

  1. Copy the 1040-ES slip: pay $17,463 by September 15, 2026, or confirm 110% safe harbor first.
  2. Or copy W-4 Step 4(c): about $3,881 extra federal withhold on each of ~9 remaining Every 2 wkss — not both unless your CPA splits them.
  3. Send last year’s 1040 to the CPA before September 15, 2026 if the harbor is unclear.
  4. Ask whether the next vest can sell additional shares to cover the gap, or if W-4 is the only lever.

Letter is optional. The slips above are the product.

How

Three steps before September 15, 2026

  1. Load a sample or type this year’s W-2, vests, and bonus.
  2. Copy the 1040-ES slip or the W-4 Step 4(c) extra — one path, not both.
  3. Optional: write one CPA letter on this device. After that, $49 unlocks 20 more. Slips stay free. Or open why it is 22% and 110% safe harbor.

FAQ

What does $49 buy?
The 1040-ES and W-4 slips are free. $49 issues CPA letters on this device after the first free one. It is a planning memo, not a filed return or tax advice.
Should I pay the 1040-ES and raise W-4 extra?
Usually pick one path. Paying the full installment and also adding Step 4(c) extra on remaining checks over-covers unless a CPA splits them. Withholding is deemed paid evenly; 1040-ES is dated when paid.
Why does this matter before September 15?
April is filing. Estimated tax is quarterly. After August 2026 the remaining federal 1040-ES dates are September 15 and January 15. Waiting until April only leaves a check and maybe a penalty.
Is the 22% on my vest the tax I owe?
No. Publication 15 lets employers withhold 22% federal on supplemental wages. Your tax is ordinary income at your marginal bracket.
Is this tax advice?
No. It is a planning memo. A CPA or EA signs the return. Read About and Method before you move money.

Sources

Reviewed August 21, 2026. About · Method.