Utilities tools

Evaluate math expressions with functions safely. Use for quick calc; for scientific history use scientific-calculator. Input: expression text. Returns numeric result. 100% client-side.

• Evaluate math expressions in real time
• Functions, constants, and variables
• Full operator precedence

Stopwatch and timer with laps in browser. Use when timing tasks; for date spans use date-calculator. Input: button controls. Returns elapsed time. 100% client-side.

• Precision stopwatch with lap times
• Start, pause, reset, and lap controls
• Export lap history

Calculate percentages, increase, and tips. Use for quick percent math; for change between values use percentage-change-calculator. Input: numbers. Returns percent result. 100% client-side.

• Percentages, change, and increase/decrease
• Quick presets for common math
• Real-time results

Estimate arrival time and duration from speed and distance. Use when planning transfers; for date math use date-calculator. Input: numbers. Returns ETA and duration. 100% client-side.

• Estimate arrival time from distance and speed
• Multiple distance and speed units
• Real-time calculation

Encode and decode geohashes. Use when sharing locations; for timezones use world-clock. Input: lat/lng or geohash. Returns geohash or coords. 100% client-side, files never leave browser.

Show current time across timezones. Use when scheduling; for timestamps use timestamp-converter. Input: timezone selection. Returns local times. 100% client-side, files never leave browser.