Month Calculator | Month Counter

This month calculator, or month counter, is a simple tool to compute the precise number of months between two given dates. In case if the number of months between the two dates is incomplete, the number of days is given instead.

So if you would like to know how many months are between two dates, you are in the right place!

Looking to calculate the exact number of months between two dates with ease? Our month calculator is designed to give you that information instantly. Here's how to use it:

1. Set the starting date: In the starting date field, pick the day, month, and year you want to start the count from.

2. Choose the ending date: Similarly, in the ending date field, select the day, month, and year that will mark the end of your calculation period.

3. Receive instant calculations: Once both dates are set, the calculator automatically computes the total number of full months between the chosen dates. If the dates span across partial months, those won't be included in the full month count. However, these will be shown in terms of number of days.

For example, if you input January 12, 2024, as the starting date and January 12, 2025, as the ending date, the calculator will show that there are precisely 12 full months between these dates.

The tool is particularly handy for planning events, calculating rent or subscriptions, or simply satisfying your curiosity about the duration between two points in time.

Dive deeper to learn more about the month calculator, its uses in various contexts, and the principles it uses to calculate time differences.

Do you know anyone who has a birthday on the 29th February? If you do, or if by chance you are the "lucky person" in question, you must know what a leap year is.

A leap year (also known as an intercalary year or bissextile year) is a calendar year that has one extra day added to keep the calendar year harmonized with the astronomical year or seasonal year.

Since the complete orbit of the Earth around the Sun takes approximately 365 days, 5 hours, 48 minutes, 45 seconds, a calendar that has only whole days in it will drift over some time. By adding (or intercalating with a technical terminology) an extra day, the difference can be eliminated. A year that is not a leap year is a common year.

Want to find out more? Why don't you check the calendar calculator or the date to date calculator? 📅

So when is leap year? In the Gregorian calendar, most years that are divisible by four are leap years. In each leap year, the month of February has 29 days instead of 28. The extra day every four years compensates for the fact that the solar year is lightly longer than 365 days. The duration of a solar year is slightly less than 365.25 days (or, more precisely, it is 365.24219 days long).

However, we must still do some further correction. If a year is exactly divisible by four, it is a leap year, except for years that are precisely divisible by 100. The exceptions are years that are exactly divisible by 400. For instance, the years 1700, 1800, and 1900 are common years, but the years 1600 and 2000 are leap years.

Translating all of the above into an algorithm, which is applied in this calculator as well, the following conditions are required to determine if a year is a leap years:

if (year is not divisible by 4) then (it is a common year)
else if (year is not divisible by 100) then (it is a leap year)
else if (year is not divisible by 400) then (it is a common year)
else (it is a leap year)

Why don't you also check the months to years calculator?

I'm Tibor, and I have extensive experience as a PhD in Statistical Methods in Economics, which has honed my data science and statistics skills. My work frequently involves planning and tracking project timelines, where calculating precise time intervals is crucial.

My inspiration for the month calculator sparked from my own need for a tool that could quickly and accurately measure the duration between two dates, a common task in both professional and personal planning. I envisioned a calculator that was not only accurate but also intuitive enough for anyone to use without a steep learning curve.

Now, this month calculator is a staple in my toolkit, aiding me in managing deadlines. It's just as useful for anyone needing to count months for financial planning, educational schedules, or personal events.

Our commitment to quality means that this calculator, like all our tools, has been meticulously tested for accuracy. We've built it to be reliable, incorporating feedback from professionals to ensure it meets the practical needs of our users.

To estimate the number of months between two dates:

1. Write down the earlier date (ED) and later date (LD).
2. If the dates occur within the same year, add the results of these formulas:
   • LD month - ED month; and
   • (LD days - ED days)/30.44.
3. Otherwise, if the dates are from different years, add the results of these formulas:
   • (LD years - ED years - 1) * 12;
   • 12 - ED month + LD month; and
   • (LD days - ED days)/30.44.

February. With only 28 days February is the shortest month of the year. This is also the only month affected by leap years. In leap years, February has 29 days instead of 28.

12 months. A leap year has exactly as many months as a normal year. The only difference is that the shortest month (February) has one extra day to synchronize our calendar year with the solar year.

The month of March took its name from the Roman calendar's first month, Martius, which at the same time, is derived from Mars, the Roman god of war and father of Romulus and Remus.