How every calculator works
Each tool is a thin interface over a pure calculation function. The math takes unformatted numeric inputs, validates them, and returns a result; the interface formats money and percentages only afterward. Commas, currency symbols, and display rounding can never change the underlying calculation, and the same functions are covered by unit tests for standard, boundary, and invalid inputs.
What each tool calculates
Every calculator on the site, its core formula, and the assumption that matters most when interpreting the result.
| Tool | What it calculates | Core formula | Key assumption |
|---|---|---|---|
| Salary Converter | Converts any pay period to all eight periods (hourly, daily, weekly, biweekly, semimonthly, monthly, quarterly, annual). | annual = amount × period multiplier; every other period is derived from the annual total | Entered work schedule (default 40 hours, 5 days, 52 weeks), editable per calculation. |
| Salary to Hourly | The hourly equivalent of an annual salary (and the reverse). | hourly = annual ÷ (hours per week × weeks per year) | Same schedule assumptions as the converter; part-time schedules change the hourly result. |
| Annual Salary | Annual gross from an hourly rate, plus a flat net estimate. | net = gross × (1 − deduction rate ÷ 100) | One flat effective deduction rate — a planning estimate, not a progressive tax calculation. |
| Overtime Pay | Regular pay, overtime pay, and the combined total for a week. | total = rate × regular hours + rate × multiplier × overtime hours | Multiplier must be at least 1; the calculator does not enforce FLSA exemption rules. |
| Salary Inflation | The salary required to keep purchasing power at an entered inflation rate. | required = reference salary × (1 + inflation ÷ 100) | The inflation rate is user-supplied; the result is the break-even salary, not a forecast. |
| Future Salary | Nominal future salary and its real (inflation-adjusted) purchasing power. | nominal = current × (1 + growth)^years; real = nominal ÷ (1 + inflation)^years | Constant growth and inflation rates over the whole period — a scenario, not a prediction. |
| Prorated Salary | Partial-month pay from an employment start date and a chosen workweek. | prorated = monthly gross ÷ scheduled workdays × eligible workdays | Working-days method; payable holidays and leave count as eligible days. |
Pay-period conversion
One known amount is annualized first. Hourly and daily values depend on the entered work schedule; the fixed periods divide the same annual total. The default schedule is 40 hours, 5 days, and 52 working weeks per year, and all three fields are editable.
Hourly: annual = hourly rate × hours per week × working weeks.
Daily: annual = daily rate × days per week × working weeks.
Weekly: annual = weekly pay × working weeks. Biweekly: annual = biweekly pay × working weeks ÷ 2.
Semimonthly: annual = semimonthly pay × 24. Monthly: annual = monthly pay × 12. Quarterly: annual = quarterly pay × 4. Annual: as entered.
Every other period is then derived from the same annual total, so the results always reconcile — a change to the work schedule moves every derived value together.
Gross and net labels
Gross pay means earnings before any deductions. The Annual Salary Calculator's net estimate applies one flat effective deduction rate to the gross total.
That flat rate is a planning approximation. It is not a progressive tax calculation, a payroll run, or a filing estimate. It ignores bracket phase-ins, the standard deduction, FICA's own caps, state differences, and pre-tax benefits. For a decision that depends on exact take-home pay, use a payroll calculator or an employer's net-pay statement.
Inflation and future value
Salary Inflation computes the break-even salary that keeps a reference income at the same purchasing power under an entered inflation rate:
required = reference × (1 + inflation ÷ 100)
Future Salary compounds a growth rate for the entered number of years, then divides the nominal result by compounded inflation to express today's purchasing power:
real = current × (1 + growth)^years ÷ (1 + inflation)^years
Both tools treat the entered rates as constant over the whole period. That makes them scenario tools, not forecasts: change the rates and you get a different, equally valid scenario.
Proration
The prorated salary calculator uses a working-days method. It builds a calendar for the actual start month from the entered start date, marks the days your workweek schedules, and counts worked days from the start date through month end.
prorated gross = monthly gross ÷ scheduled workdays × eligible days
Eligible days are worked days plus payable holidays and payable leave (the calculator currently counts worked days; the other categories are reserved for payroll-grade use). Eligible days cannot exceed scheduled workdays — the calculator rejects impossible combinations.
Employers and jurisdictions use different proration conventions — calendar-day, 30-day, and daily-rate methods all exist — so the result states this limit beside the answer.
Currency and exchange rates
Currency serves two purposes on Marketivate: it labels and formats money, and it converts figures when you switch currency. The conversion uses live exchange rates from the free exchangerate.fun API (base: USD, updated hourly), fetched directly in your browser.
converted value = value × rate(target) ÷ rate(source)
Rates are cached for up to an hour to respect the API's terms, and the selector lists every currency the API publishes (172 codes as of this writing). If live rates cannot load — an outage or a blocked request — values stay unchanged at a 1:1 ratio and the interface says so instead of pretending the rates are live.
Currency switching converts the money inputs, not schedule fields: hours, days, weeks, and percentage rates are unit-independent and never converted.
Precision and rounding
Calculations run on JavaScript numbers at full floating-point precision. Display rounds to the currency's conventional precision: two decimals for most currencies, whole units for the ISO 4217 zero-decimal set (JPY, KRW, VND, IDR, CLP, and the rest of the 19-code list).
Inputs are kept exactly as typed, and the formula trace shows the user's own values rather than rounded intermediates, so the displayed result can be reproduced by hand. Percentages are entered as numbers (for example, 22 for 22 percent) and converted inside the calculation functions, which reject rates outside their valid ranges with a plain-language message.
Review and corrections
Calculation changes require unit tests for standard, boundary, and invalid inputs before they ship. Time-sensitive claims use primary sources when available and display a review date so a stale figure is visible rather than silently trusted.
If you find an error, send a correction with the page, your inputs, the expected result, and a supporting source. We review reproducible calculation issues before changing published formulas, and we link the sources behind each calculator on its page.
What this site is not
Marketivate is an informational tool, not a payroll provider, a tax preparer, or an employment-law advisor. The calculators model common formulas; your employer, state, and contract may use different conventions that change the number that matters.
Nothing here is individualized advice. For decisions with real money attached — signing an offer, filing taxes, or disputing pay — confirm the math with the person or system that owes you the money.