Age, Date and Time Zone Calculator
Four tools that answer the awkward questions dates ask: exactly how old someone is, how many working days are left, what time it is for everyone on the call, and how long until the thing happens.
- Nothing leaves your device
- No signup
- Works offline
- Handles daylight saving
Which day counts as the birthday in a year that has no 29 February.
Enter a date of birth to see an exact age.
That is also
About that date
Coming up
Pick two dates to compare them.
Add or subtract from a date
Months and years clamp to the end of a short month, so 31 January plus one month is 28 or 29 February.
Clock changes in the next three weeks
Meeting planner
Green is inside working hours, amber is an hour or two either side, grey is the middle of the night. A highlighted row works for everyone.
The countdown is anchored to a real moment, so everyone watching sees the same number wherever they are.
Pick a date and time to start counting.
Saved countdowns
Nothing saved yet. Saved countdowns stay on this device.
Common questions
Is this really free, and is there a catch?
It is free with no account and no usage limit. The page is static files on a free host, so once it has loaded there is nothing left to pay for and nothing to charge you for.
Does anything I type get sent anywhere?
No. Every date, label and saved countdown stays in your browser's local storage on this device. There is no server and no database. Clearing your browser data removes it; nothing is kept anywhere else.
How does it handle 29 February birthdays?
Someone born on 29 February turns a year older on 28 February in a common year, which is the convention most legal systems use, and you can switch it to 1 March if you prefer. Either way the arithmetic walks the calendar rather than dividing by 365.25, so the answer matches what a person would count.
Does the time zone converter get daylight saving right?
Yes, including the two cases most converters get wrong. When clocks spring forward an hour simply does not exist, and when they go back an hour happens twice — the tool says so instead of silently picking one. It reads the time zone database your browser already ships, so the rules stay current without an update.
Why does the business-day count differ from my payroll system?
Usually because of two settings: whether both endpoints count, and which days are your weekend. Both are adjustable here, and you can add public holidays. Friday-Saturday weekends are a single click.
Can I use the results commercially?
Yes. The numbers are yours to use however you like, with no attribution. They are arithmetic, not advice — for anything with legal or financial consequences, check against the rules that actually govern it.