Calculate Days Between (DAYS360) Including Start Date

Hello,

I have an inquiry regarding calculating the number of days between two dates, using DAYS360, when all months are assumed to be 30 days. For reference, we bill all months as 30days, 360 days a year. That being said there are a couple exceptions regarding February.

• If the Start Date <= February 1 and the End Date = February 28, February is considered to have 30 days, plus the number of days from the Start Date, i.e. 1/15/2023 - 2/28/2023 = 46 days, or 2/01/2023 - 2/28/2023 = 30 days.
• If the Start Date >= February 2 and the End Date is <= February 28 then February is calculated by actual days, i.e. 2/2/2023 - 2/28/2023 = 27 days.
• If the Start Date = February 28 and the End Date > February 28, then February is considered to have 3 days, plus the number of days until the End Date, i.e. 2/28/2023 - 3/15/2023 = 18 days.

I have tried using a simple =DAYS360($A2,$B2)+1 but the results vary, depending on the month. 10/01/2022 - 12/31/2022 should be 90 days, but DAYS360 +1 make it 91, whereas 10/01/2022 - 9/30/2023 calculates 359 if I don't put the +1 to include the Start Date.

Additionally, I have tried using =DAYS360($A2,$B2)+(IF(AND(MONTH($B2)=2,DAY($B2)=28),2,0))+1, which works to an extent, but I run into the same issues described above.

Any help is greatly appreciated and all notes are contained here and in the spreadsheet.

you don't provide examples for leap years however, given O365, perhaps below would work for you ?

Formula:

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the above would "spill" the 13 results into F2:F14 (mirroring expected values)

Good morning,

I haven't been with my organization through a leap year, but the concept should remain the same as the examples above. If the Start Date is February 29, then it would add two days to include the Start Date and February 30. However, I believe there are controls in place that prevent Start Dates from occurring on February 29 due to background processes, such as these. If February 29, why not February 28? Why not March 1?

What is "s", "e", and "m" in this equation? I have never seen or used these before.

Is this correct?

And how many days are
31 May to June 1 (2 or 1?),
31 May to 31 May (1 or 0?) and
31 May to 30 June (31 or 30?)

30 May to 1 June = 2 days
31 May to 1 June = ? days
1 June to 1 June = 1 day

30 May to 30 June = 31 days
31 May to 30 June = ? days
1 June to 30 June = 30 days

1 May to 31 May = 30 days
2 May to 31 May = 29 days
29 May to 31 May = 2 days
30 May to 31 May = 1 day
31 May to 31 May = ? days