Free tools to work out ages, count days between dates, add or subtract time, and track milestones. Instant, accurate and private.
Age and Milestones
5 toolsWork out an exact age, compare two ages, or find the date of a milestone.
Date Math
11 toolsCount the days between dates, add or subtract time, and skip weekends.
Everyday and Seasonal
10 toolsFun and practical date tools for planning around real life.
Counting time, made simple
Date arithmetic is the kind of thing that is easy to get slightly wrong by hand, especially once leap years, month lengths and weekends are involved. These calculators do the counting for you and show a clear, exact answer in whatever unit you need, from a precise age down to the day to the number of working days before a deadline.
Pick the right tool
To find how old someone is, use the age calculator. To count the span between two dates, the date calculator handles it in days, weeks or months. Need a future or past date instead? Days from date adds or subtracts any number of days, and the business-days calculator does the same while skipping weekends, which is what you want for delivery and project dates.
Accurate and private
Each tool accounts for leap years and varying month lengths, so the counts are exact. Everything runs in your browser, so the dates you enter stay on your device and nothing is saved.
Types of Date and Time Calculation
The tools here fall into three families. Age and milestone calculators measure the time from a birth date or event to today. Date math tools add or subtract days, weeks, months and years, or count the gap between two dates. Everyday and seasonal tools handle recurring needs like business days, fortnights, week numbers and countdowns. Choosing the family first makes the exact tool obvious.
When You Need a Date or Time Calculator
Date and time maths comes up more often than most people expect. Planning a project deadline means counting business days around weekends and holidays. Booking travel or leave means knowing the exact date a number of days or weeks ahead. Anniversaries, ages and countdowns turn a rough idea into an exact figure, and payroll or billing cycles often run fortnightly or monthly. A calculator removes the guesswork and the off-by-one errors that come from counting on a wall calendar.
Key Date and Time Terms
- Leap year
- A year with 366 days, adding 29 February to keep the calendar aligned with the seasons.
- Business day
- A weekday, Monday to Friday, excluding weekends and usually public holidays.
- Fortnight
- A period of 14 days, or exactly two weeks.
- Week number
- The position of a week in the year, from 1 to 52 or 53, under the ISO 8601 standard.
- UTC
- Coordinated Universal Time, the global reference clock that time zones are measured against.
Explore Other Calculators
Beyond dates and time, browse the rest of the site.
- Financial Calculators - loans, budgets and investments.
- Converters - units, measures and everyday conversions.
- Math Calculators - percentages, algebra and geometry.
- Health Calculators - BMI, calories and body metrics.
Frequently asked questions
How do I count the days until a date?
Use the date calculator or days-from-today tool: enter the target date and it returns the exact number of days, weeks and months from today.
What is a fortnight in days?
A fortnight is 14 days, or exactly two weeks. Pay, rent and scheduling cycles are often set fortnightly.
How do I add business days to a date?
Use the business days calculator: enter a start date and a number of working days, and it skips weekends and holidays to give the resulting date.
How is exact age calculated?
The age calculator counts complete years from the birth date to today, then the remaining months and days, accounting for leap years and the different lengths of each month. That gives an exact age rather than a rounded number.
Do these tools count leap years correctly?
Yes. Every date calculation includes leap years and the correct number of days in each month, so spans and future dates are accurate.
What is the difference between days-between and business-days?
Days-between counts every calendar day in a span. The business-days calculator counts only Monday to Friday, skipping weekends, which is the right choice for work deadlines and shipping estimates.
Are these date calculators free and private?
Yes. They are free with no sign-up, and they run entirely in your browser, so the dates you enter are never stored or sent anywhere.
Reviewed by Prof. Dr. Khalil Mudassar, PhD
Formulas and methods on this page are checked for accuracy against standard references. View profile
These date and time calculators are provided for general information. Results are based on the standard calendar and the dates you enter. For legal, medical or official deadlines, always confirm the date with the relevant authority.
Author
Hamza Shakeel is the Chief Technology Officer at MultiCalculators.com, responsible for the platform's technical architecture, calculator engine performance, and infrastructure reliability. He leads engineering efforts focused on site speed, mobile responsiveness, Core Web Vitals optimization, and security. Hamza ensures every calculation runs accurately and instantly across all devices, while maintaining the platform's stability and scalability as it grows. His work directly supports the seamless, trustworthy experience users expect from MultiCalculators.com.
Areas of Expertise: Web Engineering, Core Web Vitals, Site Performance, Calculator Logic, Cloud Infrastructure, Security