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A growing collection of calculators and tools — built for speed, designed for clarity, free to use.

10 tools available

Percentage Calculator

Calculate percentages instantly — find X% of Y, what percent X is of Y, and percentage change between two numbers.

Calculate tips and split bills between any number of people. Supports custom tip percentages and per-person breakdowns.

Compound Interest Calculator

See how your savings or investments grow over time with compound interest. Includes monthly contribution support.

Calculate your exact age in years, months, and days from your date of birth. Also shows days until your next birthday.

Calculate your Body Mass Index using height and weight. Supports both metric and imperial units with health range indicators.

Paycheck Calculator

Estimate your take-home pay after federal and state tax withholding for all 50 US states.

Mortgage Affordability Calculator

Find out how much house you can afford based on income, debts, down payment, and interest rate using the 28/36 rule.

Markup & Margin Calculator

Instantly convert between markup and margin percentages. Calculate selling price, profit, and cost from any starting point.

TDEE & Calorie Needs Calculator

Calculate your Total Daily Energy Expenditure and daily calorie targets for weight loss, maintenance, or muscle gain.

Time Zone Converter

Convert times between any world time zones instantly with DST-aware accuracy and a live world clock.