Free date and time calculators: age calculator, date difference, time zone converter, countdown timer, zodiac calculator, and stopwatch. India IST-aware calculations.
Every calculator on iCalcApp is free with no sign-up, and no data collection. Calculations run instantly in your browser — your inputs are never sent to our servers.
All formulas are reviewed by Mayra, and cross-verified against official sources (RBI, WHO, ICMR, ISO).
iCalcApp date and time tools include age calculator, date difference calculator, countdown timer, hours worked calculator, online stopwatch, time zone converter, and zodiac sign calculator. All are free, instant, and work in any browser without an app.
All iCalcApp date calculators account for leap years automatically. A leap year occurs every 4 years (divisible by 4), except century years (divisible by 100) which are not leap years — unless also divisible by 400. So 2000 was a leap year, 1900 was not. February has 28 days in regular years and 29 in leap years. The calculator applies these rules for any date range.
All time-based calculations use your device's local time by default. The Age Calculator shows your age based on today's date in your local timezone. The Countdown Timer counts down to midnight local time unless you specify a time. The Time Zone Converter lets you choose any UTC offset or major city timezone explicitly.
Everything time-related lives here: the age calculator, countdown timer, date calculator, hours calculator, stopwatch, time zone converter, and the zodiac calculator. Each opens instantly, calculates in real time as you type, and explains its formula with worked examples below the tool.
Use the Date Calculator: enter your start date and end date, then click Calculate. The result shows the exact number of days, weeks, months, and years between the two dates, accounting for different month lengths and leap years. You can also reverse the calculation to find a date N days in the future or past.
The Age Calculator subtracts your birth date from today's date, counting complete years, then remaining months, then remaining days. Born March 15 1990, today June 5 2026: exactly 36 years, 2 months, and 21 days. It also shows the day of the week you were born and the number of days until your next birthday.
Use the Time Zone Converter: select your current city or UTC offset, enter the local time, then select the target city. The converter shows the equivalent local time. Key offset to remember: India Standard Time (IST) is UTC+5:30 — 5.5 hours ahead of UTC, 10.5 hours ahead of US Eastern Standard Time.
Enter a future date and time using the date picker. The countdown displays days, hours, minutes, and seconds remaining, updating every second using JavaScript's Date object. Keep the browser tab open for uninterrupted counting. The timer is accurate to within 1 second and handles daylight saving time changes automatically.
If your birth date falls within 2–3 days of a sign boundary, use the Zodiac Calculator — it uses exact astronomical boundary dates, not rounded approximations. The calculator also shows your Chinese zodiac animal, element (fire/earth/air/water), modality (cardinal/fixed/mutable), and ruling planet.
Sources: IANA Time Zone Database; ISO 8601 — Date and time representation; ILO Working Time Database; World Athletics record database.
For more utility tools, visit our online tools.
The age calculator finds your exact age in years, months, days, hours, and minutes from date of birth to today or any target date. Handles leap year birthdays (February 29) correctly. Use cases: legal age verification, insurance forms, passport applications, and retirement eligibility.
The date calculator finds the exact number of days, weeks, months, or years between any two dates. Essential for contract deadlines, loan tenure calculations, project planning, and anniversary counting. Add or subtract any number of days from a date to find a future or past date.
The countdown timer counts down to any future date or event — exams, birthdays, product launches, weddings. Supports Pomodoro technique (25-minute work intervals) and event countdown displays. Lap recording available for interval training.
The hours calculator finds exact hours and minutes between any two clock times, including across midnight (for night shifts). Calculates overtime hours under Indian Factories Act rules. Supports multi-segment shift calculation.
The stopwatch provides millisecond-accurate timing with lap recording using the browser's performance.now() API. Suitable for sports timing, reaction time testing, and productivity tracking.
The time zone converter converts between any two time zones globally. Includes IST to EST, IST to GMT, IST to SGT, and all major time zones. India does not observe DST — IST remains UTC+5:30 year-round, which affects scheduling with DST-observing countries twice yearly.
The zodiac calculator finds your Western zodiac sun sign, Chinese zodiac animal, and Celtic tree sign from your date of birth.
| Task | Best Tool |
|---|---|
| Calculate exact age in days | Age Calculator |
| Days until exam or event | Countdown Timer or Date Calculator |
| Find hours between two shift times | Hours Calculator |
| Convert IST to New York time | Time Zone Converter |
| Time a workout or study session | Stopwatch |
| Calculator | Best for | Example |
|---|---|---|
| Age Calculator | Exact age in years, months, days; legal age verification | "How old am I on 15 August 2026?" → 24 years, 3 months, 12 days |
| Date Calculator | Days between dates; add/subtract days from a date | Contract signed 1 March, 90-day payment due → 29 May |
| Hours Calculator | Hours between clock times; shift duration; overtime | 9:15 AM to 6:30 PM = 9 hours 15 minutes |
| Countdown Timer | Days/hours to an event; exam date; project deadline | "Days until UPSC exam: 47 days, 3 hours" |
| Stopwatch | Precise timing with lap recording; sports timing | 100m sprint: 12.4s; lap 1: 45.2s, lap 2: 47.8s |
| Time Zone Converter | IST to EST/GMT/SGT; schedule international meetings | 9:00 AM IST = 3:30 AM UTC = 11:30 PM EST (previous day) |
| Zodiac Calculator | Western sun sign, Chinese zodiac, Celtic tree sign | Born 15 March 1990 → Pisces ♓, Horse 🐴, Ash tree |
The date calculator counts total calendar days. To get working days, subtract Saturdays, Sundays, and national/bank holidays. India has 3 national holidays (Republic Day, Independence Day, Gandhi Jayanti) plus state-specific and bank holidays. For a precise working-day count, use the date calculator for total days, then manually subtract weekends and holidays from a RBI holiday calendar.
Age is typically counted in completed years. A person born on 15 June 2000 turns 26 on 15 June 2026 — not 25 on 14 June 2026. The iCalcApp age calculator counts completed years, months, and days. For leap-year birthdays (February 29), the age calculator uses February 28 as the effective birthday in non-leap years for legal purposes.
IST (Indian Standard Time) is UTC+5:30. GMT (Greenwich Mean Time) is UTC+0. India is always 5 hours 30 minutes ahead of GMT. Unlike GMT, India does not shift its clocks seasonally, so the IST–GMT offset is always fixed at +5:30. This means IST is 5:30 ahead of GMT in winter and summer alike.