How the calculators work

Each calculator works out its answer in your browser, and the same rules run on our server so the page shows a right answer even before the calculator starts. Nothing you type is stored. With the page’s script on, nothing is sent either; without it, the “Work it out” button sends what you typed to our server so that it can show the answer, and we don’t keep it. Money is counted in whole cents: each line of a worksheet is kept to the cent, and an amount is rounded to the dollar only where the official method says so (North Carolina withholding, the North Carolina return). All figures were checked against the documents below on October 29, 2026.

Gross pay

• A salary a year is divided by the number of paychecks: 52 weekly, 26 every two weeks, 24 twice a month, 12 monthly, rounded to the cent. A salary “each paycheck” is used as typed.
• Hourly pay: the hours you work in a week times your rate. With the overtime box ticked, hours over 40 in a week are paid at one and a half times the rate, as the federal Fair Labor Standards Act requires for most hourly workers, and G.S. 95-25.4 at employers the federal law does not cover. A year is 52 such weeks, shared evenly between the paychecks: exact for weekly and two-weekly pay, an average for twice a month and monthly.

Deductions before tax

A 401(k), 403(b) or governmental 457(b) contribution comes off the pay that federal and North Carolina income tax are worked on, but not off Social Security and Medicare pay. Health, dental and vision premiums through a cafeteria plan, and an HSA or FSA through the plan, come off all of them, as Publication 15-B sets out. After-tax deductions (a Roth 401(k), union dues) come off the take-home pay only.

Federal income tax

Worksheet 1A of IRS Publication 15-T (2026), the method for automated payroll systems, line by line, with the 2026 annual tables (standard, or the Step 2 checkbox tables). For a 2020-or-later Form W-4: the paycheck’s taxable pay times the paychecks in a year, plus Step 4(a), less Step 4(b), less $12,900 if married filing jointly or $8,600 otherwise when the Step 2 box is not checked; the tax from the table row; divided by the paychecks; less the Step 3 credits for one paycheck ($2,200 for each child under 17 and $500 for each other dependent in a year); plus Step 4(c). For a W-4 from 2019 or earlier: $4,300 for each allowance, and the single or married table. Each line of the worksheet is kept to the cent. Publication 15-T also lets employers round the tax to the nearest dollar, or use printed wage-bracket tables, so a real paycheck can differ by a dollar or so.

Social Security and Medicare

Social Security is 6.2% of the pay after cafeteria-plan deductions, until the year’s pay reaches $184,500 in 2026; Medicare is 1.45% of all of it, and the employer withholds 0.9% more Additional Medicare Tax on pay above $200,000 in the year, whatever the filing status (Publication 15; Social Security Administration). Each is rounded to the nearest cent. The calculator’s yearly figures add up the paychecks one by one, so they stop Social Security at the paycheck where the year’s pay passes the limit. For 2027 the Social Security limit will be $192,300 (Social Security Administration, October 14, 2026).

North Carolina income tax

The annualized method of Form NC-30 (2026): the paycheck’s taxable pay times the paychecks in a year, less $12,750 ($19,125 for head of household) and $2,500 for each allowance on Form NC-4, times 4.09% (the 3.99% tax rate of G.S. 105-153.7 plus 0.1%), divided by the paychecks and rounded to the nearest whole dollar; then any extra amount from line 2 of the NC-4. Married filers use $12,750 too, as NC-30 says. Employers may also use NC-30’s percentage method or its wage-bracket tables, which can differ by a dollar. A bonus paid on its own is withheld at a flat 4.09%.

Bonuses

A bonus paid on its own: 22% federal income tax, and 37% on the part of the year’s bonuses and other supplemental pay above $1 million (Publication 15, section 7); 4.09% North Carolina tax (Form NC-30, section 12); Social Security and Medicare as above. Added to a regular paycheck: the tax on the two together, less the tax on the regular paycheck alone, for federal and for NC.

The North Carolina return for the year

Federal adjusted gross income, plus North Carolina additions, less North Carolina deductions from it (G.S. 105-153.4); less the larger of the NC standard deduction ($12,750 single or married filing separately, $19,125 head of household, $25,500 married filing jointly or surviving spouse) and NC itemized deductions, with mortgage interest and property tax together capped at $20,000; less the child deduction, from $3,000 down to $0 for each child under 17 depending on income and filing status (G.S. 105-153.5); times 3.99%, to the nearest dollar. Against the tax withheld, that gives the refund or the amount still owed. The calculator also shows the same taxable income at the 2027 rate of 3.49% set by Session Law 2026-41.

NC-4 allowances

The Allowance Worksheet of Form NC-4, Part II, line by line: itemized deductions above the standard deduction, plus the child deduction and adjustments, less nonwage income and NC additions, one allowance for each $2,500 (rounded down); one for each $103 of NC tax credits (rounded down); for married filing jointly, 5 allowances when the spouse’s wages and taxable retirement pay are $250 or less, down to 1 at $10,250 or less, and none above that (5 for a surviving spouse); less what the spouse claims.

The take-home pay table

Each salary paid every two weeks in 2026, single or married filing jointly on both the W-4 and the NC-4, with nothing else claimed: no dependents, no allowances, no deductions before tax. The same rules as the paycheck calculator work out every cell, and the CSV file under the table holds every amount on each check.

What the calculators do not do

• They don’t work out the federal tax you will owe for the year, or the federal deductions for tips and overtime, which are claimed on the federal return or through Step 4(b) of the W-4.
• They don’t cover pensions, self-employment, or work in another state.
• They don’t know your employer’s own deductions, or a garnishment.

Each new year

The figures change every January. When the IRS publishes the new Publication 15-T and the North Carolina Department of Revenue the new Form NC-30, usually in December, the calculators and every page that states a figure are updated, and each page shows the day its figures were checked. For a question about your own withholding, the IRS’s Tax Withholding Estimator works from your whole year.

Updated October 29, 2026