Date Calculator Pro is the fastest way to calculate the exact number of days, weeks, months, and years between two dates — plus add or subtract time, find business/working days, calculate age, and track countdowns to any event, all in one simple app. Whether you need a day between dates calculator for planning, a business days calculator for deadlines, an age calculator for birthdays, or a countdown timer for a big event, Date Calculator Pro handles it accurately and instantly — no internet connection required. WHY DATE CALCULATOR PRO? ✓ Days Between Dates Calculator Instantly find the exact duration between any two dates in years, months, weeks, days, hours, minutes, and seconds. Perfect for tracking anniversaries, project timelines, deadlines, and important milestones. ✓ Works Across Nearly 10,000 Years — 01/01/0001 to 12/31/9999 Unlike most date calculators that break outside a narrow 1900–2100 window, Date Calculator Pro accurately calculates dates and durations from January 1, year 1 all the way to December 31, 9999 — a true full-range date engine for historical research, genealogy, academic work, or any calculation far outside a typical calendar year. ✓ Add or Subtract Days from a Date Quickly calculate a future or past date by adding or subtracting days, weeks, months, or years — ideal for planning due dates, expiry dates, and reminders. ✓ Business Days & Working Days Calculator Calculate working days between two dates while automatically excluding weekends and custom holidays — a must-have tool for HR, payroll, shipping estimates, and contract deadlines. ✓ Age Calculator Find your exact chronological age in years, months, and days — a precise, reliable age calculator built right into the app. ✓ Countdown to Any Date Set a countdown to birthdays, holidays, weddings, exams, or any event and see exactly how much time is left. ✓ Day of the Week Finder Instantly determine what day of the week any past or future date falls on. ✓ Leap Year Checker Check whether any year is a leap year in one tap. ✓ Customizable Date Formats & Time Zones Choose the date format you prefer and view your device's current time zone directly in settings. ✓ Custom Color Themes (Pro) Personalize the app with custom color themes instead of one fixed look — make Date Calculator Pro match your style, not the other way around. ✓ Clean, Ad-Free, Offline Design (Pro) Enjoy the full Date Calculator experience without ads, with a fast, lightweight interface that works completely offline — your dates and calculations are never uploaded or shared. WHO USES DATE CALCULATOR PRO? Project managers and freelancers tracking deadlines and billing cycles, HR and payroll teams calculating working days, event planners counting down to weddings and launches, expecting parents tracking due dates, students calculating exam countdowns, and anyone who needs a fast, accurate date difference calculator or date duration calculator for everyday life. PRIVACY FIRST Date Calculator Pro works fully offline. Your dates and personal information stay on your device — nothing is collected or shared. We're always improving Date Calculator Pro. If you run into an issue or have a feature request, please reach out to us directly at [email protected] before leaving a review — we read every email and respond quickly. If you enjoy the app, a quick rating helps other people find it and helps us keep building. Download Date Calculator Pro now and get the most accurate date calculator, business days calculator, and age calculator in one app.