DATEDIF for date differences in Excel - Cheat Sheet & Quick Revision

Recall & Review

beginner

What does the DATEDIF function do in Excel?

DATEDIF calculates the difference between two dates in days, months, or years.

beginner

What is the correct syntax for the DATEDIF function?

DATEDIF(start_date, end_date, unit)
Where unit can be "Y", "M", "D", "MD", "YM", or "YD".

beginner

What does the unit "Y" mean in DATEDIF?

It returns the number of complete years between the start_date and end_date.

intermediate

How does the "MD" unit in DATEDIF work?

It returns the difference in days, ignoring months and years. For example, difference in days between the days of the two dates.

intermediate

Why might DATEDIF sometimes give unexpected results?

Because it is an undocumented function in Excel and can behave oddly with invalid dates or if start_date is after end_date.

What does the formula =DATEDIF("2023-01-01", "2024-01-01", "Y") return?

A 1

B 12

C 365

D 0

The unit "Y" returns the number of complete years between the two dates, which is 1.

Which DATEDIF unit returns the difference in months ignoring years?

A MD

B M

C Y

D YM

"YM" returns the number of months between dates ignoring years.

If start_date is after end_date, what happens with DATEDIF?

A Returns negative number

B Returns #VALUE! error

C Returns #NUM! error

D Returns zero

DATEDIF returns a #NUM! error if start_date is after end_date.

What does the unit "D" in DATEDIF calculate?

A Difference in days ignoring months and years

B Total difference in days between two dates

C Difference in days ignoring years

D Difference in days ignoring months

"D" returns the total number of days between the two dates.

Which of these is NOT a valid unit for DATEDIF?

A WD

B YD

C MD

D YM

"WD" is not a valid unit for DATEDIF.

Explain how to use DATEDIF to find the number of complete months between two dates.

Remember the unit for months is "M" and start_date should be before end_date.

Describe the difference between the DATEDIF units "MD" and "D".

Think about whether months and years are considered in the calculation.

Practice

1. What does the Excel function =DATEDIF(A1, B1, "M") calculate?

easy

A. The number of years between the dates in A1 and B1

B. The number of days between the dates in A1 and B1

C. The sum of the dates in A1 and B1

D. The number of complete months between the dates in A1 and B1

Solution

1. Step 1: Understand the DATEDIF function parameters

   The function takes a start date, an end date, and a unit to measure difference.

2. Step 2: Interpret the unit "M"

   "M" means the difference in complete months between the two dates.

3. Final Answer:

   The number of complete months between the dates in A1 and B1 -> Option D

4. Quick Check:

   DATEDIF with "M" returns months [OK]

Hint: Use "M" to get months difference, not days or years [OK]

Common Mistakes:

• Confusing "M" with days or years
• Putting the later date first causing errors
• Thinking it sums dates instead of difference

2. Which of the following is the correct syntax to find the number of days between dates in cells A2 and B2 using DATEDIF?

easy

A. =DATEDIF(B2, A2, "D")

B. =DATEDIF(A2, B2, "D")

C. =DATEDIF(A2, B2, "Days")

D. =DATEDIF(A2, B2, D)

Solution

1. Step 1: Check the order of dates

   The earlier date must be first, so A2 then B2 is correct.

2. Step 2: Verify the unit parameter

   "D" in quotes is the correct unit for days; "Days" or D without quotes is invalid.

3. Final Answer:

   =DATEDIF(A2, B2, "D") -> Option B

4. Quick Check:

   Correct syntax uses "D" and earlier date first [OK]

Hint: Always put earlier date first and use "D" in quotes [OK]

Common Mistakes:

• Swapping start and end dates
• Using unit without quotes
• Using incorrect unit names like "Days"

3. Given A1 = 2023-01-15 and B1 = 2024-03-10, what is the result of =DATEDIF(A1, B1, "Y")?

medium

A. 14

B. 2

C. 1

D. 0

Solution

1. Step 1: Understand the dates and unit "Y"

   "Y" returns the number of complete years between the two dates.

2. Step 2: Calculate complete years from 2023-01-15 to 2024-03-10

   Only one full year (2023-01-15 to 2024-01-15) has passed.

3. Final Answer:

   1 -> Option C

4. Quick Check:

   DATEDIF with "Y" counts full years only [OK]

Hint: DATEDIF "Y" counts full years, ignore partial months/days [OK]

Common Mistakes:

• Counting partial years as full
• Confusing "Y" with months or days
• Misreading date formats

4. You entered =DATEDIF(A1, B1, "M") but got a #NUM! error. What is the most likely cause?

medium

A. The end date in B1 is earlier than the start date in A1

B. The unit "M" is not valid for DATEDIF

C. You forgot to put quotes around "M"

D. The dates are not formatted as text

Solution

1. Step 1: Understand #NUM! error in DATEDIF

   This error happens if the start date is after the end date.

2. Step 2: Check the order of dates in A1 and B1

   If B1 is earlier than A1, DATEDIF returns #NUM! error.

3. Final Answer:

   The end date in B1 is earlier than the start date in A1 -> Option A

4. Quick Check:

   #NUM! means start date > end date [OK]

Hint: Ensure start date is before end date to avoid #NUM! error [OK]

Common Mistakes:

• Swapping dates causing negative difference
• Using invalid units without quotes
• Assuming date format causes error

5. You want to calculate the total number of months and days between two dates in A1 and B1, showing result as "X months and Y days". Which formula correctly does this?

hard

A. =DATEDIF(A1,B1,"M") & " months and " & DATEDIF(A1,B1,"MD") & " days"

B. =DATEDIF(A1,B1,"M") + DATEDIF(A1,B1,"D") & " months and days"

C. =DATEDIF(A1,B1,"YM") & " months and " & DATEDIF(A1,B1,"D") & " days"

D. =DATEDIF(A1,B1,"Y") & " months and " & DATEDIF(A1,B1,"MD") & " days"

Solution

1. Step 1: Understand the units needed

   "M" gives total complete months, "MD" gives leftover days ignoring months and years.

2. Step 2: Combine these with text to form the phrase

   Concatenate months, text, and days correctly using & and quotes.

3. Final Answer:

   =DATEDIF(A1,B1,"M") & " months and " & DATEDIF(A1,B1,"MD") & " days" -> Option A

4. Quick Check:

   Use "M" and "MD" units combined with & for text [OK]

Hint: Use "M" and "MD" units with & to combine months and days [OK]

Common Mistakes:

• Adding months and days instead of concatenating
• Using wrong units like "YM" or "Y" for months
• Forgetting quotes around text parts