Use this calculator anytime you require something better than just the age difference between the two birth dates. Your computer will calculate the result for you immediately using your web browser without having to download any software or perform the calculations yourself.
The calculator will be able to help you with questions such as “How much older am I than my friend? “Also, you can use this calculator for comparisons between partners, spouses, brothers/sisters, parents/children, fellow students, colleagues, family members, or even historical persons. Using the actual birth dates is much more accurate than current age or birth year only.
To calculate the time between the dates of births, simply subtract the date of birth that occurs earlier from the date of birth that occurs later. In the end, the answer should include the whole years and then the rest of the months and days.
This page does all of the above automatically for you and calculates also the same amount of time in months, weeks, days, hours, minutes, and seconds.
How to Use the Tool
- Provide an optional name for Person A and then pick the first date of birth.
- Provide an optional name for Person B and then pick the second date of birth.
- Check the result after providing both the valid dates. You don’t have to click any calculate button separately.
- Click Copy to copy the result to your clipboard, Save to create a visual record, and Reset to start all over again.
There is no effect of the order of the two persons on the span between them. The one whose date of birth is before the other is the elder person, and the one whose date of birth is after the other is the younger person.
What the Results Mean
Exact Calendar Gap
The main output shows the interval in the form of completed years, remaining months, and remaining days. This option is most suitable for comparing birthdays since this takes into account calendar months and not equal numbers of days in every month.
Total Months
The value derived in the total months will give all the years in terms of 12 months, while adding any additional months to give the final result. The total months will be good if you want to view the interval as a single month figure.
Total Weeks
The value in weeks is the actual number of weeks present in the interval between the two dates. Any additional day, which cannot be considered as a week, is added to the total number of days.
Total Days
It is the exact number of calendar days present in the gap between the two birthdays. This is particularly useful in case of nearby birthdays, sibling comparison, anniversaries, and other situations where the total years would not suffice.
Total Hours, Minutes, and Seconds
They are calculated using the total number of days present in the interval. As dates are used for calculating the results, the total days will consist of full calendar days without considering any hour or time zone difference.
Upcoming Birthdays
The last part of the output shows the upcoming birthdays, together with the day of the week, which can be helpful for future celebrations. It is quite easy to see from the information whether the next birthday will take place for both people.
Example: Two People Born 15 Years Apart
If Person A was born on July 20, 1991, and Person B was born on July 20, 2006.
The precise result is:
15 years, 0 months, and 0 days
However, the same period can be expressed in this way:
- 180 months in total
- 782 weeks in total
- 5,479 days in total
- 131,496 hours in total
- 7,889,760 minutes in total
- 473,385,600 seconds in total
As the people were born in the same month and on the same day, it results in an exact number of years. Otherwise, the months and days left would also appear in the result.
Why Full Birthdays Are More Accurate Than Ages
A birthday age difference calculator works with the month, day, and year for both persons. Such an approach gives you the full calculation based on the calendar, not the approximation.
Age comparison alone cannot give you an accurate value because there are still months and days between two ages. In our case, it looks like 18 years and 22 years are 4 years different, but actually, there are some extra months and days in the difference.
Comparison of the birth years gives you even more inaccurate results. The years 2015 and 2030 are 15 years different on the calendar, but actually, the difference will depend on the month and day of these years.
In contrast to a regular age difference calculator, which subtracts only the numbers of years, this calculator considers full dates of birth. Use the main age calculator to calculate someone’s age on the particular date.
How the Calendar Calculation Works
The process starts off by determining which of the birthdays came first and which was later. The year, month, and day of the early birthday are compared with those of the latter.
Wherever there is a negative value of the day component, the calculator adds up the required number of days from the previous month of the calendar. In case the month difference is negative, it takes one year and 12 months.
The result after normalization consists of:
- Full years
- Leftover full months
- Leftover days of the calendar
There is a second process for calculating the exact number of days that have passed since the two dates. Then this number is used to calculate the full number of weeks, hours, minutes, and seconds.
This algorithm considers the true number of days in the month as well as leap years. It doesn’t assume that all months or all years contain the same number of days.
Exact Gap Versus Total Duration
The result obtained using the calendar and total unit calculation methods covers the same period differently.
While a result like 3 years, 4 months, and 12 days is an interval covered using calendar units, a result like 1,230 days represents the same interval but in one continuous form.
Employ the first method whenever an easy-to-understand comparison of birthdays is required. Employ the second method for any comparison where the period must be represented as one continuous unit.
Common Ways to Use the Result
Friends and Family
Use this calculator to determine how many years and days one friend is older than another, to make a comparison between brothers and sisters, to calculate birth intervals for different children, and to determine intervals for birthdays spanning several generations.
When comparing ages for siblings, the calculator becomes especially useful when their birthdays are too close to each other to allow a correct subtraction of years from their birth years.
Couples, Dating, and Marriage
Partners and spouses will find it useful as an impartial metric of the span between their birthdays. While a partner age difference calculator will provide the chronological distance between two dates, it cannot tell anything about compatibility, maturity, consent, and the overall relationship state.
A dating or marriage comparison should be taken as impartial factual data regarding the calendar. The comparison cannot be seen as any kind of recommendation or approval of a potential or actual relationship.
Parents and Children
Parents can compare the distance between the birthdays of their children or get the age at which they had a certain baby by using the dates of birth involved.
In case of comparing the ages directly, you need to enter both birthday dates of the parent and the child or use a dedicated tool for this purpose.
School, Teams, and Community Groups
The calculator will help you compare classmates, teammates, club members, or co-workers whenever you need to know something about their age intervals.
You can save the result for yourself; however, you cannot consider it as an alternative for official papers when any verification is needed.
Senior Age Comparisons
The tool accepts valid birth dates of people of all ages, starting from infants through adults to senior citizens. Input full birth dates when comparing the ages of your seniors, celebrating important birthdays, and exploring family history.
Retirement Timeline Conversations
Use the result when you want to have a discussion about how long it will take before one spouse reaches particular age-related points.
This site is not a retirement plan calculator, pension calculator, savings plan, investment plan, or Social Security benefits calculator. The tool calculates only the age gap between two dates of birth.
Genealogy and Historical Research
It is possible to input the birth dates of your relatives or historical persons when the full birth date is known. If the birth years are known, it is possible to calculate only the age difference in years, but not months and days.
Understanding Age Differences/Gaps in Relationships
There is no single age that can be used to determine whether a particular relationship would be proper or improper. The appropriate age difference calculator can only provide you with the age gap between the dates of birth.
It does not take into consideration:
- The law or any other requirement
- Consent
- Maturity levels of the individuals
- Life stage compatibility
- Power dynamics
- Personal values or beliefs
- Shared plans and future goals
Therefore, it should be used as a simple comparison tool rather than something more serious. It cannot replace legal, medical, psychological, or any other type of counseling.
In cases where the legal requirements or consent matters, check the necessary criteria from a lawyer or from the concerned authority.
How to Calculate the Age Difference in Excel/Google Sheets
Enter the earlier date in cell A2 and the later one in cell B2. You can use the DATEDIF formula to calculate the difference in years, months, and days.
=DATEDIF(A2,B2,"Y")&" years, "&DATEDIF(A2,B2,"YM")&" months, "&DATEDIF(A2,B2,"MD")&" days"
If you do not know which one is the earlier date, use the MIN and MAX formulas to arrange the dates accordingly.
=DATEDIF(MIN(A2,B2),MAX(A2,B2),"Y")&" years, "&DATEDIF(MIN(A2,B2),MAX(A2,B2),"YM")&" months, "&DATEDIF(MIN(A2,B2),MAX(A2,B2),"MD")&" days"
DATEDIF can be used in Excel or Google Sheets when calculating the difference in days, months, or years between two dates. But the month-end date and leap-day situation might create some surprises, so the important calculations need to be checked carefully.
Future Age Comparisons
The time elapsed between two birthdays will never change because the people will age at the same speed.
The completed ages of the people can seem to be one year closer or farther than they are because one of them has had his/her birthday while the other hasn’t yet. The time span between the birthdays is still the same.
For instance, the people can say about themselves that they are 30 and 25 years old, but after having his/her birthday, the younger person becomes 26 while the older one is still 30 years old, although their time elapsed since birth doesn’t change.
What This Tool Does Not Calculate
This calculator allows you to compare two birthdays by means of the Earth-based Gregorian calendar. However, it cannot calculate the following things:
- The number of years someone is alive on Mercury, Mars, and other planets
- The difference between biological age and chronological age
- Astrology and zodiac compatibility
- If there is success in your relationship
- Recommended dating ages
- How much money you can get at retirement
- Social Security benefits
- Any proof of your age that is legal or medical in nature
- Comparing time of birth
Two individuals who have been born on the same date will consequently be reported to have zero days of life difference, even if the time of birth was different for each one.
Accuracy and Calculation Details
Fill in the entire month, day, and year of both persons to get the most informative and accurate result.
Consider the following information:
- Only years of birth give just an approximate result.
- Age rounded up may obscure the differences in months and days.
- Months are counted using the total days and not by dividing the total days by the average length of a month.
- Weeks mean the full number of seven days.
- Hours, minutes, and seconds are counted in full calendar days.
- No exact birth time and time zone are used.
- It is just informative and cannot be regarded as the official proof of age.
Why Use the Calculator Online Instead of Simple Subtraction?
Manual calculation may be problematic in case one of the birthdays occurs earlier in the month, in case the date contains the month of February, or in case the period includes one or more leap years.
The calculator automatically takes into account the calendar borrowing and the number of days in each month. Moreover, it provides the result in several time units at once.
Since the calculator functions online, it can be used on any phone, tablet, laptop, or desktop computer without having to download an age difference calculator application.
Related Tools
Use an age calculator whenever you have to calculate someone’s current age or age on some particular past or future date.
Use a generic date difference calculator for situations where dates are involved but are not related to birthdays, such as project dates, contract deadlines, travel, events, deadlines, etc.
Use this calculator here whenever your primary purpose is to calculate how far apart two persons are in terms of their ages according to the dates of their births.
Frequently Asked Questions
What is an age difference calculator?
This is a calculator that calculates the difference between two birthdays by indicating the difference in years, months, and days. Advanced calculators show the difference in the period in total months, weeks, days, hours, minutes, and seconds.
What is the use of an age difference calculator?
You can calculate the age difference between the dates of birth of your friends, brothers and sisters, couple, spouse, relatives, classmates, co-workers, historic personalities, or between any two persons whose dates of birth are known to you.
How do you calculate the age difference?
Just enter the two dates of birth. The calculator will subtract the earlier date from the latter and indicate the difference in terms of the number of completed years, months left, and days left.
How do you calculate the age difference mathematically?
You need to subtract the year, month, and day of the earlier date from the year, month, and day of the latter. In case the day or month difference is negative, you need to borrow some days from the month or 12 months from the previous year.
Is there any way I can determine the age difference between two people online?
Yes, the online age difference calculator is done instantly within your browser and shows you the result when you put in two valid birth dates.
Can I measure the age difference between two people in any order?
Yes, the calculator calculates the absolute period between the two birth dates, so the order of Person A and Person B doesn't affect the outcome.
Is an age difference calculator using birthdays and ages the same thing?
No, the full birthday dates give you the correct result, whereas the ages may give you only an approximate difference in years.
Is there any advantage of the birthday difference calculator over the one using birth years?
Yes, the comparison of birthdays is based on the month and the day as well, and the comparison of the birth years can be off by up to a year.
Is this a good age difference calculator for the date of birth?
Yes, input two dates of birth and get the calendar difference as well as its decomposition into other time units.
Can it calculate the age difference between two dates?
The calculator uses two dates, which are the birthdays of people. Use the generic date calculator when the dates are not of birth but related to any projects, agreements, travel, schedules, and so forth.
Can it calculate the age difference between two years?
Two dates in different years can be inputted. However, only subtracting the years will provide you an approximate age difference and will not take into account other months and days.
Can it calculate the age difference in years and months?
Yes, years, months, and remaining days are the main result of the calculation.
Can it calculate the age difference in months?
Yes, years and months are united to produce a sum of total months of the age difference.
Can it calculate the age difference in days?
Yes, days are the total result of the difference between two dates of births.
Are there weeks, hours, minutes, or seconds in the results?
Yes, weeks, hours, minutes, and seconds are calculated on the basis of day differences. The exact time of birth is not taken into account.
How old am I compared to my friend?
Insert the birthdays of both individuals. Whose birthday comes first? The output will give an exact number of years, months, and days that exist between you two.
Is there a calculator for who is older by date of birth?
Yes, the one with the earliest date of birth is older. The interval that is shown gives an exact number of years between the birth dates of these people.
How much age difference is there between 18 and 22?
The general difference between ages is four years. Yet, the specific age difference could be a little more complicated. Therefore, the full date of birth is necessary for a correct answer.
Can it be used by couples to calculate their age gap?
Yes, a couple will be able to see how old they are from the perspective of years between their birthdays. The result has nothing to do with compatibility, relationship, maturity, and eligibility.
Can I use it to calculate the age difference before marriage?
Yes, enter the birth dates of the couple to get the exact age difference. It does not tell whether it is a good marriage or not.
Can it be used as a sibling age difference calculator?
Yes, by inputting the dates of birth of both siblings, you will get the number of years, months, and days between the siblings' birthdays.
Is it a Social Security calculator for people having an age difference?
No, this calculator doesn't calculate anything regarding Social Security. It is not intended to offer any advice on Social Security.
Can it calculate Social Security benefits at certain ages?
No, it only measures the span of time from one birthday to another. No earnings record, no eligibility status, and no calculation of benefits and strategies of claiming them are applied.
How can I calculate the age difference between two dates in Excel?
You need to apply the DATEDIF function with the earlier date as the starting point and the later date as the ending point and then use the Y, YM, and MD parameters for years, months, and days.
Does it work similarly to an age gap calculator app?
Yes, the tool offers you similar conveniences like an age gap calculator app, but you will not have to install anything since it works in a web browser.
