A free world clock, time-zone and planning toolkit
Around the world
A starting set of cities — customise the full board in the world clock.
Find a tool and learn how to use it
Check a time abroad
Translate a dated appointment across cities, including changes of day and daylight-saving offsets.
Start a focus session
Learn the Pomodoro routine, how to choose a task and what to do during a break.
Plan a realistic workday
Make room for focused work, meetings and the interruptions your calendar needs to absorb.
Put the plan on paper
Open a printable daily planner for priorities, time blocks and notes.
What ChronoClock is for
Time, read correctly
The clocks, converter and meeting planner exist because time-zone arithmetic goes wrong in predictable ways: a call booked across a daylight-saving change, a deadline set in a zone nobody named, a Sunday evening in Sydney that is still Sunday morning in New York. Every zone rule comes from the IANA database your browser already ships, so the offsets here are the ones your operating system uses, not a copy that can drift out of date.
Sunrise, moon phases and season dates are computed from the standard equations and are accurate to about a minute, which is enough for planning a walk and not enough for navigation. Each page says which.
Focus and planning without an account
The Pomodoro and interval timers, task lists, habit tracker, planners and calculators keep everything in your browser's local storage. Nothing is uploaded, there is no sign-up, and clearing site data removes it, so export what you want to keep. The team rooms are the one exception: planning poker, retros and polls share state through a server so that people in different places see the same board, and those rooms expire on their own after a period of inactivity.
The tools are deliberately small. A timer is a timer, a matrix is a matrix, and each one explains what it does and does not measure before you start.
Guides that check the research
The articles behind the tools are written from the primary studies rather than from other blog posts, including where the popular advice does not hold up. The 25-minute Pomodoro was an arbitrary choice by its inventor, the often-quoted 23 minutes to recover from an interruption comes from interviews rather than from any published study, and the willpower-depletion studies that underpin much productivity advice have largely failed to replicate. Where the evidence is thin the guide says so and suggests what to try instead.
Start with the guides index or pick a tool below. Everything is free and works without an account.
Tools
How ChronoClock works
The live clocks use your device's time and its available IANA time-zone rules. Keep automatic time enabled and your browser updated; the board does not correct an inaccurate system clock. Use the converter to check offsets for a future date.
Sunrise, sunset, moon phases and season times are calculated estimates. Use them alongside the weather forecast when planning outdoors, allowing for local terrain and conditions that a city-level calculation cannot capture.
Covering 182 cities across 98 time zones.