Methodology and Sources (Tax Year 2026)

Figures verified against the sources below on September 25, 2026

Figures used

Item	2026 value	Official source
Federal withholding method	Pub. 15-T Worksheet 1A, percentage method tables for automated payroll (W-4 2020 or later)	IRS Pub. 15-T (2026)
Worksheet 1A line 1g	$12,900 married filing jointly; $8,600 otherwise; $0 if the Step 2 box is checked	IRS Pub. 15-T (2026)
W-4 Step 3 amounts	$2,200 per qualifying child under 17; $500 per other dependent	Form W-4 (2026)
Social Security	6.2% up to a $184,500 wage base	IRS Pub. 15 (2026)
Medicare	1.45%, no cap; 0.9% Additional Medicare withheld on wages over $200,000	IRS Pub. 15 (2026)
Federal supplemental rate	22%; 37% above $1 million	IRS Pub. 15 (2026)
401(k)/403(b) elective deferral limit	$24,500	IRS Notice 2025-67
Georgia rate	4.99% flat (withholding at 4.99% from May 11, 2026; 5.19% before)	GA DOR Employer’s Withholding Tax Guide 2026, rev. June 2026; HB 463
Georgia standard deduction (withholding)	$15,000 for G-4 status A, B, D; $30,000 for status C	GA DOR guide, Tables E/F; Form G-4
Georgia allowance	$5,000 a year per dependent or adjustments allowance	GA DOR guide, Tables E/F
Georgia supplemental (bonus) rate	The income tax rate in effect when paid: 4.99% from May 11, 2026	GA DOR guide
Local income tax	None withheld in Georgia	GA DOR guide; ACCG
Overtime	Federal FLSA: 1.5× after 40 hours in a workweek; no separate Georgia rule	Georgia DOL

Per-paycheck Georgia amounts

The Georgia percentage method uses the DOR's printed per-period amounts rather than dividing annual figures: for example, the biweekly standard deduction is $576.92 (status A, B, D) or $1153.85 (status C), and each allowance is $192.31. This matches how employers calculate it.

How amounts are calculated

Federal withholding is calculated per paycheck and multiplied by the number of paychecks for the annual figure. Amounts are rounded to the cent; the IRS wage-bracket tables round to whole dollars, so they can differ by up to $0.50 per paycheck.
Social Security and Additional Medicare are figured on annual wages and shown per paycheck as an even average. In practice Social Security stops once your year-to-date wages hit $184,500, and Additional Medicare starts once they pass $200,000.
401(k)/403(b) contributions are excluded from federal and Georgia income-tax wages but included in Social Security and Medicare wages. Health, dental and vision premiums and HSA/FSA contributions are treated as section 125 cafeteria-plan deductions, which are excluded from all three.
Hourly pay assumes 52 weeks a year, with overtime hours paid at 1.5 times the regular rate.
Salary and hourly pages use standard assumptions stated on each page: biweekly pay; single (W-4 single, G-4 status A) or married filing jointly with one earner (W-4 married filing jointly, G-4 status C); no deductions.

Testing

Automated tests must pass before any update is published. They cover:

hand-worked cases for every federal filing status, every G-4 status and every pay frequency;
the Social Security wage base, Additional Medicare, the 401(k) limit, pre-tax deductions, W-4 Steps 2 through 4, and zero or invalid inputs;
the Georgia DOR's worked examples from its 2026 guide ($27.03 and $0.00);
a comparison of our federal math against all 4,350 cells of the IRS 2026 wage-bracket tables for weekly, biweekly, semi-monthly and monthly pay. Every cell matches to within the IRS's whole-dollar rounding.

Methodology and Sources (Tax Year 2026)

Figures used

Per-paycheck Georgia amounts

How amounts are calculated

Testing

All sources