This page explains how SalaryIncreaseCalc computes raises. If a marketing sentence and this page disagree, trust this page — and tell us.

Core formulas

Every number on this page comes from the same formulas the calculator uses. Intermediate results keep full precision; currency and percentages are rounded only when displayed (typically to cents or two decimal places).

  • New salary from percent: new = salary × (1 + pct ÷ 100)
  • Raise amount: amount = new − salary
  • Raise percent from two salaries: pct = (new − old) ÷ old × 100 (requires old > 0)
  • Raise by dollar amount: new = salary + amount in the selected pay period
  • Hourly ↔ annual: annual = hourly × hoursPerWeek × 52 (default 40 hours → 2,080)
  • Other periods: weekly × 52, biweekly × 26, semi-monthly × 24, monthly × 12
  • Real raise after inflation: ((1 + raise/100) ÷ (1 + inflation/100) − 1) × 100
  • Multi-year projection: salary × (1 + rate)^year for year 0…n; optional real series divides each nominal point by (1 + inflation/100)^year
  • After-tax increase (planning estimate): raiseAmount × (1 − marginalRate − ficaRate) with ficaRate defaulting to 7.65%

Validation rules

Salary (and period pay) must be greater than zero. Raise percents must fall between −100 and 1,000. Empty or non-numeric inputs show a clear error message instead of a blank or broken result.

Data sources

  • Arithmetic identities above — definitional, not surveyed.
  • FICA employee rates: 6.2% Social Security (up to the annual wage base) + 1.45% Medicare = 7.65%, as published in IRS payroll guidance for standard employee withholding below the Social Security wage base. Our planning estimate applies 7.65% to the raise amount only — it does not model Additional Medicare Tax, mid-year wage-base exhaustion, or employer-side FICA. When we ship a bracketed federal model, rates will live in versioned data files with an explicit IRS source and retrieval date.
  • Inflation default: an editable field (commonly initialized near recent CPI-style ballpark figures). You should replace it with the index you care about (CPI-U, personal CPI, or a contract COLA clause).
  • Benchmark articles: cite named surveys (for example BLS wage data, WorldatWork, Mercer, WTW) with year and link on the page that uses them. Those citations are refreshed when new waves publish.

How estimates differ from payroll

A payroll system computes net pay from your tax elections, year-to-date wages, state and local rules, benefits, and garnishments. Our after-tax line does none of that detail. It multiplies the raise by one minus a single marginal rate minus FICA. That answers “roughly how much of this raise might show up in take-home?” — not “what will my next pay stub say?”

Likewise, period conversions assume a steady hours-per-week schedule without overtime multipliers, unpaid leave, or varying shifts. Semi-monthly (24) is not the same as biweekly (26); we expose both so you can match your actual calendar.

Update policy

Methodology is updated whenever formulas, defaults, or tax-model assumptions change, and when major IRS or survey inputs we cite are revised. The page header shows the current stamp (November 1, 2026). Changes follow a creator-then-reviewer process: creators never review their own work, and reviewers check formulas and claims before publication. See the editorial policy and corrections page for cadence and reporting.

  1. Formula or validation changes ship with checks against the worked examples on the homepage.
  2. Tax data updates (when introduced) record source document and date inside the data file.
  3. Each affected page gets a new “Updated” stamp (November 1, 2026 on this revision).
  4. Material methodology changes are summarized here so readers can see what shifted.

Reproducing a number

Worked-example tables call the same formulas as the interactive calculator when the page is published, so a formula change updates both together. Pick a homepage worked-example cell (for example 5% on $40,000 → $42,000), enter the same inputs in the calculator, and compare. If they disagree, that is a bug — email info@salaryincreasecalc.com.