Kalc vs Anywhen

Unit Converter, Calculator, and World Clock. The simple & clean UI to get the results you need for everyday use as quickly as possible.

Anywhen is the all-in-one time calculator — every calculation that revolves around time, done properly, on a phone that never needs a connection. WHAT IT DOES • Duration between two dates or times — with daylight-saving handled correctly, not approximated • Add or subtract time — days, weeks, months, years, or exact hours and minutes • Age calculator — exact age, next birthday, age on a given date • Business days — count or add working days, with custom workweeks and holiday calendars • Time-zone converter — one moment, many zones, historically accurate • World clock — your favourite cities at a glance • Meeting planner — find a slot that works across up to 8 people and their working hours • Timers and stopwatch — timers survive a restart or reboot • Countdowns and streaks — days until, days since • Calendar info — ISO week, day of year, quarter, leap years • Duration arithmetic — add up hours and minutes like an adding machine • Unit converter — every time unit at once • Timestamp tools — Unix epoch, ISO 8601, RFC 3339, RFC 2822, HTTP date • Recurrence calculator — work out repeating schedules • Sunrise and sunset — for any city, fully offline HOME-SCREEN WIDGETS Six widgets that actually earn their place: a world-clock strip, an event countdown, a days-since counter, a two-zone comparison, today's calendar facts, and your next timer. CORRECTNESS IS THE POINT Most time calculators quietly get the hard cases wrong. Anywhen is built on the IANA time-zone database, uses exact integer arithmetic with no floating-point date math, and is tested against thousands of property-based cases covering daylight-saving transitions, leap years, and the awkward zones with 30- and 45-minute offsets. When a result depends on a convention — what "one month later" means from January 31st, or which instant to use when a clock jumps — Anywhen tells you which rule it applied instead of hiding it. PRIVATE BY DESIGN No account. No sign-up. No ads. Every calculation works with no connection — your dates, timers and events stay on your device and are never uploaded. Anywhen does record anonymous statistics about which tools get used, so we know what to improve next; that never includes what you type, and you can switch it off in Settings. We never sell or share your data. ACCESSIBLE Full dark and light themes, dynamic type support, and right-to-left layout.