Finance

Finance Calculators

Plan money decisions with free finance calculators — including the flagship GS Pay Calculator for official OPM General Schedule salaries, the Tip Calculator (with every US state sales-tax page), discounts, loans, California paycheck estimates, and sales tax tools.

7 live · 7 tools in this cluster

How to Calculate a Tip →

Calculators in this category

GS Pay Calculator2026 GS pay by grade, step, and locality. Annual, biweekly, monthly, and hourly from official OPM tables — free federal salary calculator.
Tip CalculatorCalculate tip, sales tax, and grand total. Pre-tax or post-tax toggle, round up, split the bill — free US tip calculator.
California Paycheck CalculatorEstimate California take-home pay after federal, CA state, and FICA taxes. Free CA-only paycheck calculator.
Sales Tax Calculator (California)Add or remove California sales tax with example city rates or a custom %. Free CA tax estimator.
Loan Payoff CalculatorPayoff date, interest, extra payments, biweekly option, or payment needed for a target term. Free loan planner.
Discount CalculatorFind sale price and savings from any discount percent. Optional sales tax estimate — free, no signup.
Currency ConverterConvert USD, GBP, and CAD with clear static reference rates. Free planning converter — no paid FX API.

Related calculators

How these finance tools work

Each calculator runs entirely in your browser with transparent formulas — no paid APIs for core math.
Federal GS pay uses OPM published base tables and locality percentages; update the data file when OPM releases a new January schedule.
Tip math supports pre-tax vs post-tax bases, optional sales tax, round-up, and per-person splits; state pages pre-fill local rates.
State paycheck and sales-tax tools document their tax year and assumptions on each page.