Calculators & Number Tools
Find the right calculator for everyday arithmetic, date planning, work schedules, conversions, programming, and number formatting.
Everyday calculations
Calculate percentages, units, scientific expressions, ages, and dates.
- Percentage Calculator - Calculate percentages, percentage change, reverse percentages, and more
- Unit Converter - Convert between units of length, weight, temperature, volume, speed, area, data, and time
- Scientific Calculator - Full scientific calculator with trig, logarithms, constants, and calculation history
- Age Calculator - Calculate exact age in years, months, and days
- Date Calculator - Advanced date operations with timezone support
Dates, schedules, and goals
Plan countdowns, ranges, work hours, calendar events, and tracked habits.
- Date Countdown Calculator - Create custom live countdown timers to any future date with Web Audio alarms
- Date Range Calculator - Calculate the exact number of days, weeks, months, or years between two dates
- Work Hours Calculator - Calculate daily and weekly work hours, lunch breaks, and gross pay earnings
- Add to Calendar Link Generator - Generate shareable 'Add to Calendar' buttons and .ics files for your events
- Free Online Habit Tracker & Goal Planner - Track your habits, build daily streaks, and view progress with GitHub-style heatmaps
Developer and number utilities
Convert bases, estimate tokens, format numbers as words, or solve specialized sums.
- Number Base Converter - Convert numbers between binary, octal, decimal, and hexadecimal instantly
- Token Calculator - Count tokens for OpenAI, Claude, and popular open-source models
- Numbers to Words Converter - Convert numbers, decimals, and currency amounts into English words
- Roman Numerals Converter - Convert standard numbers to Roman numerals and translate Roman numerals to base-10 integers
- Cross Sum Calculator - Calculate the cross sum (sum of digits) and the digital root of any number step-by-step
- Vanity Number Calculator - Translate phone numbers into memorable vanity words and decode word numbers back
- Counter Online - Create, count, and manage multiple tally lists with custom increments and sounds