Calculate days since last birthday

[sobrien1234]

I want to calculate the days since someone's last birthday. In cell A1 I have today's date and in cell B1 I have their date of birth. In cell C1 I want a formula that calculates the days since their birthday (not the days since their date of birth). Any suggestions?

 

[alansidman]

Look at this link on how to use the DateDif function.

https://www.techonthenet.com/excel/formulas/datedif.php

 

[Dave Patton]

Excel 2010
	A	B	C
1	24-Oct-17	5-May-85	172
2	24-Oct-17	20-Oct-90	4
3	24-Oct-17	31-Oct-12	358
4	24-Oct-17	25-Oct-50	364
5
2b

Cell Formulas
Range	Formula
C1	=A1-DATE(YEAR(B1)+DATEDIF(B1,A1,"y"),MONTH(B1),DAY(B1))
C2	=A2-DATE(YEAR(B2)+DATEDIF(B2,A2,"y"),MONTH(B2),DAY(B2))
C3	=A3-DATE(YEAR(B3)+DATEDIF(B3,A3,"y"),MONTH(B3),DAY(B3))
C4	=IF(DATE(YEAR(TODAY()),MONTH(B4),DAY(B4))>A4,A4-DATE(YEAR(TODAY())-1,MONTH(B4),DAY(B4)),A4-DATE(YEAR(TODAY()),MONTH(B4),DAY(B4)))

 

[AhoyNC]

Another option:
Copy formula in C2 down as needed.

Excel Workbook
	A	B	C
1	today	Birthday	# Days from today
2	10/24/2017	1/14/1980	283
3	10/24/2017	2/12/1975	254
4	10/24/2017	3/12/1980	226
5	10/24/2017	4/10/1960	197
6	10/24/2017	5/9/1980	168
7	10/24/2017	6/7/1980	139
8	10/24/2017	7/6/1961	110
9	10/24/2017	8/4/1980	81
10	10/24/2017	9/2/1980	52
11	10/24/2017	10/24/1952	0
12	10/24/2017	10/30/1980	359
13	10/24/2017	11/28/1980	330
14	10/24/2017	12/27/1980	301
Sheet