Paycheck Calculator with Custom Deductions

How It Works

Gross pay is what your employer pays you; net pay is what reaches your bank account. The gap between them is your deductions, and this calculator works through them one by one. Start with gross pay per pay period, then subtract federal withholding, state withholding, FICA (Social Security and Medicare), your retirement contribution, and any insurance or other fixed deductions. What is left is your net pay. The formula is simple — net = gross − deductions — but the deductions themselves are where the confusion lives, so each one gets its own line in the results.

This calculator deliberately does not estimate your federal or state withholding from tax tables. Withholding depends on your W-4, your filing status, your other income, and your pay frequency, and a generic estimate is often wrong by enough to mislead. Instead, you enter the withholding figures straight from your pay stub — the numbers your employer actually takes. FICA, by contrast, is a fixed percentage for most employees: 6.2% for Social Security plus 1.45% for Medicare, or 7.65% combined, which is the default in the form. Your 401(k) contribution is also a percentage of gross pay, and insurance is usually a fixed dollar amount.

Pay frequency matters for the annual figures. A bi-weekly worker gets 26 paychecks a year, a semi-monthly worker gets 24, and a monthly worker gets 12 — so the same per-paycheck amount means different annual totals. There is also a quirk worth knowing: bi-weekly workers get three paychecks in two months of most years, because 26 pay periods do not divide evenly into 12 months. Those "extra" paychecks are a good moment to top up an emergency fund or make an extra debt payment.

Worked Example

Gross pay of $2,500 bi-weekly with federal withholding of $280, state withholding of $95, FICA at 7.65% ($191.25), a 5% 401(k) contribution ($125), and $85 of insurance. Total deductions are $280 + $95 + $191.25 + $125 + $85 = $776.25. Net pay per paycheck is $2,500 − $776.25 = $1,723.75. Over 26 paychecks, annual gross is $2,500 × 26 = $65,000 and annual net is $1,723.75 × 26 = $44,817.50 — about 69% of gross pay reaches the bank account, and the rest goes to tax, retirement and insurance.

Assumptions and What This Calculator Leaves Out

• All deductions are entered by you. The calculator does not estimate federal or state withholding from tax tables — use the figures from your pay stub.
• FICA is applied as a flat percentage of gross pay. In reality, the 6.2% Social Security portion stops above the annual wage base, and an additional 0.9% Medicare tax applies above a high-income threshold — neither is modelled here.
• It assumes the same gross pay and deductions every period. Overtime, bonuses and commission change real paychecks from period to period.
• It does not model pre-tax vs post-tax ordering: in reality, a traditional 401(k) contribution reduces taxable income, which can lower federal withholding slightly.
• It does not include local or city income tax, union dues, garnishments, or other less common deductions — add those to "Insurance & other" if they apply.

Net pay per bi-weekly paycheck at different gross amounts, using the same deductions as the worked example (federal $280, state $95, FICA 7.65%, 401(k) 5%, insurance $85):

Because the fixed deductions ($280 + $95 + $85 = $460) stay the same while the percentage deductions grow with pay, net pay rises faster than gross pay in dollar terms — but the share of gross pay you keep also rises, from 56.7% at $1,500 to 75.9% at $4,000. In reality the fixed deductions would not stay flat — federal withholding rises with income — so treat this table as an illustration of the arithmetic, not a prediction.

How to Use This Calculator

Enter your gross pay per pay period and your pay frequency, then fill in each deduction from your most recent pay stub: federal withholding and state withholding as dollar amounts, FICA and retirement as percentages, and insurance and other fixed deductions as a dollar amount. The results show each deduction, your total deductions, your net pay per paycheck, and your annual gross and net. Use the Reset button to return to the worked example.

Tips and Practical Advice

Budget from your net pay, never from your gross. The worked example shows why: $65,000 a year sounds like $5,417 a month, but the money that actually arrives is $44,817.50 a year, or about $3,735 a month. Building a budget on the gross figure is the fastest way to overspend every month. If your employer offers a 401(k) match, contribute at least enough to get the full match — it is the only part of the deductions list that is actually extra pay, not a cost.

Check your pay stub at least once a year against this calculator. Withholding errors, missed deductions and wrong FICA rates all happen, and they are much easier to fix when spotted early. And if you get a raise, run the numbers before celebrating: a $200-a-month raise is not $200 in your pocket — after tax, FICA and a percentage-based 401(k) contribution, it is closer to $130–$150, depending on your deductions. Knowing the real number keeps the raise from disappearing into lifestyle creep.

FICA employee rate: 6.2% Social Security + 1.45% Medicare = 7.65% (standard employee rate). No withholding tables are used — all deductions are entered by you. Last reviewed: 13 November 2026.

Frequently Asked Questions