AgeCalc FAQ

A1: An age calculator that runs in your browser. It gives an exact age in years, months and days, with hours, minutes and seconds counting up live, the age on any past or future date, a countdown to the next birthday, milestones such as 10,000 days, and one ring for every year lived. Fourteen date tools sit beside it, from the difference between two dates to an age limit check for exam forms, and a Birthdays tab keeps the family's birthdays. Nothing is uploaded and there is no account.

A2: Nothing. It is free, with no registration and no limits. Like every page on ZeroDataUpload, it is supported by advertising.

A3: No. Open the page in any modern browser (Chrome, Edge, Firefox, Safari or Opera) on a computer, tablet or phone. Your settings and saved birthdays are kept in that browser; there is nothing to sign in to.

A4: No. Every age and date is worked out in this browser, and nothing you type into the tool is sent to a server. The page itself loads the site's ads and analytics, as every page on the site does; the Privacy Policy explains those, and your dates are never part of them.

A5: On the calendar, the way people say their age. AgeCalc counts the whole calendar months from the date of birth to the chosen day, splits them into years and months, and adds the days since the last month was complete. Someone born on 15 August 1990 is 36 years, 2 months and 19 days old on 3 November 2026: 434 whole months bring us to 15 October 2026, and 19 days follow.

A6: Many calculators divide the days lived by 365.25 or treat a month as 30 days, and then disagree by a day or two, most often near a birthday or at the end of a month. AgeCalc counts real calendar months, so the age goes up exactly on the birthday. The totals in weeks and days are plain counts of the days between the two dates, so they agree with any calendar.

A7: When the next month has no 31st, the month is complete on its last day. Born on 31 January, you are one month old on the last day of February (28th, or 29th in a leap year), and two months old on 31 March. The same rule applies to the 29th and 30th in February.

A8: In years without 29 February the birthday is counted on 28 February by default. In Settings you can choose 1 March instead, which is the rule in some countries such as the United Kingdom. The choice decides the day the age goes up, the countdown, the milestones counted in months and the day the calendar file repeats on.

A9: Without it, hours, minutes and seconds are counted from midnight at the start of the birth date. With a birth time they are counted from that moment, so the seconds, the hours and the milestones such as a billion seconds are exact to the minute. Years, months and days do not change. The time is read in your device's time zone.

A10: The whole years plus the share of the way from the last birthday to the next one. Halfway between two birthdays the decimal part is about .50, and on a birthday it reads exactly .00. Some forms and studies ask for an age in this form.

A11: Yes. Change Age on below the date of birth to any date, past or future: the age, the totals and the cards below all follow it, and the live seconds stop. Today brings back the live count. The Age on a date tool does the same for another person without changing the Age tab.

A12: One ring for every full year lived, drawn like the rings in a tree trunk, with a darker ring every ten years and a label on the decades. The amber arc is the year you are in now; its length shows how far it is to the next birthday. Point at a ring or tap it to see the dates of that year and the weekday its birthday fell on, or focus the rings and step through them with the arrow keys. Each date of birth gives its trunk a slightly different shape.

A13: Round numbers of days (from 100 to 40,000, with 10,000 and 12,345 among them), weeks (100 to 5,000), months (100 to 1,000), hours, minutes and seconds (up to 3 billion seconds), and birthdays on Mars, Jupiter and Saturn. The next four upcoming and the last two passed are shown; All milestones opens the full table. Each upcoming one has a calendar button.

A14: Add to calendar every year saves a small standard calendar file (.ics) with a yearly repeat; a milestone saves a file for that one day. Open the file on your phone, or import it into Google Calendar, Outlook or Apple Calendar. Add all to calendar on the Birthdays tab saves one file with every saved birthday. The files are made in your browser and saved straight to your device.

A15: Yes. On the Birthdays tab the year is optional. Without it, the list still shows the day and how many days are left, but not the age the person turns. Add the year later with the edit button.

A16: By whose birthday comes next, then by name, in four groups: today, the next 30 days, the next three months and later. A search box appears once you have eight or more names. The age button on a row shows that person's full age on the Age tab.

A17: Not by default: from Monday to the next Monday is 7 days. Tick Count the end date too to add one day, as when you count the days of a trip or a leave. The result gives years, months and days, the totals, the working days for the weekend you choose and the weekend days, and it skips any days off you list.

A18: The result is the last day of February, because February has no 31st, and a note under the result says so. Years and months are added first, then weeks, then days, then hours, and each step is listed when there is more than one.

A19: Enter the date of birth, the cut-off date from the notice (age as on), the minimum and the maximum age and any extra years for a category. Most notices mean the maximum as under that age: 21 to 32 years as on 1 August 2026 allows dates of birth from 2 August 1994 to 1 August 2005. Choose Up to the end of that age if a notice counts the maximum year in. The result says eligible, too young or too old and prints the allowed dates of birth; always compare them with the notice.

A20: Tick the retirement option in Reaching an age. Under the Indian central government rule (FR 56), an employee retires on the last day of the month in which the retirement age is reached, and someone born on the first of a month retires on the last day of the month before. Other employers, states and countries can follow other rules.

A21: The day the older person is exactly twice the age of the younger one, which is the day the younger one is as old as the gap between them. Parents and children reach it when the child is as old as the parent was at the birth. The tool also gives the combined age today and the day the two ages together reach 100.

A22: From the charts many vets use, which grow fast in the first two years: a cat, or a dog of most sizes, is about 15 in human years at one and 24 at two. After that, dogs age at a rate that depends on their adult size, so pick small, medium, large or giant. For dogs over a year old the tool also shows an estimate from a 2020 study of Labrador retrievers, and the old rule of seven years for one only for comparison.

A23: They are rounded national figures for life expectancy at birth from recent years, for women, men or both, for 48 countries and the world average; published sources differ slightly. They describe a whole population, not one person, and are not medical advice. Life in weeks draws one square per week of life against the average.

A24: Yes. The times come from your browser's own time zone rules, so summer time and its changes are applied for every city. Pick a city to compare from, drag the slider or type a time to see the time elsewhere at that moment, and add up to 30 cities or time zones.

A25: AgeCalc uses the modern Gregorian calendar for every year from 1 to 9999. Before 1582 (and later in some countries) people used the Julian calendar, which by then was ten days behind. The Day of the week tool notes this when you pick such a date.

A26: AgeCalc's date difference gives working days for a weekend you choose and a list of days off you type, as one part of a general date calculation. WORKDAYS is the site's business days calculator: it knows the public holidays of ten countries for any year, half days, deadlines, batches and leave planning. For counting business days, use WORKDAYS; for ages and everyday date sums, use AgeCalc.

A27: In your browser's storage on this device, under the tool's own name: your date of birth and birth time, the saved birthdays, the inputs of each tool and your settings. The light or dark theme is shared with the rest of the site. Nothing is stored anywhere else.

A28: Yes. Turn off Remember my date of birth in Settings. The date then stays only while the page is open and is forgotten when you close it; saved birthdays and settings are still kept.

A29: Copy link puts the date of birth in the address (for example #age/1990-08-15), so the person who opens it sees the same age. That also means anyone who sees the link sees the date. Share it only where you are happy for that date to be seen.

A30: In Settings, Save a backup file writes one file with your birthdays, settings, tool inputs and date of birth. In the other browser, Restore from a backup reads it and asks whether to add the birthdays to the list there (entries with the same name and date are skipped) or to replace everything.

A31: Settings, Delete everything, then confirm. It removes the date of birth, the saved birthdays, the tool inputs and the settings that AgeCalc keeps, and nothing else of the site. Deleting one birthday from the list can be undone for a few seconds from the notice that appears.

A32: The line under the date boxes spells the date out, so check it. The order of the boxes follows Settings, Date order (day-month-year, month-day-year or year-month-day); it starts from your browser's language, so a browser set to American English starts with the month. Change it once and every tool follows.

A33: Paste the whole date into any box. Forms such as 15/08/1990, 15-08-1990, 15 Aug 1990, August 15 1990 and 1990-08-15 are read; a two-digit year is taken as the most recent such year. If a date cannot be read, a notice says so and shows examples.

A34: The browser's site data was cleared, or this is a private window, another browser or another profile. AgeCalc has no copy anywhere else, so save a backup file now and then and keep it.

A35: Hours, minutes and seconds count the real time that has passed in your device's time zone, so a summer time change since the birth adds or removes an hour from the clock reading but not from the time lived. Add the birth time for an exact count.