Sum figure of annual range for different starting points

[aquelious]

Hi everyone,

I have been asked to look at a query in excel and I'm fairly stumped in fairness.
I have attached an image for reference.
Essentially, What I'm looking to get is an amount in column C that provides me with the sum amount for the person in column A, for a 12 month period from the start date in column B.
For example, Dave started in April - 2019, so I need the sum amount from column G to column R.
As all the start dates are different I wasn't sure how to create a formula that would achieve this.

Any help would be very much appreciated.

 

[Fluff]

If row 1 & column B are real dates based on the first day of the month how about

=SUM(FILTER(D2:Y2,($D$1:$Y$1>=B2)*($D$1:$Y$1<EDATE(B2,12))))

 

[AlanY]

try this

Book1
	A	B	C	D	E	F	G	H	I	J	K	L	M	N	O	P	Q	R	S	T	U	V	W	X	Y	Z
1				Jan-19	Feb-19	Mar-19	Apr-19	May-19	Jun-19	Jul-19	Aug-19	Sep-19	Oct-19	Nov-19	Dec-19	Jan-20	Feb-20	Mar-20	Apr-20	May-20	Jun-20	Jul-20	Aug-20	Sep-20	Oct-20	Nov-20
2		Apr-19	12	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1
3		Sep-19	12	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1
4		Jan-19	12	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1
5		Apr-20	8	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1
6		Feb-19	12	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1
7		Jun-20	6	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1
8		Jul-19	12	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1
Sheet1

Cell Formulas
Range	Formula
C2:C8	C2	=SUMIFS(D2:Z2,$D$1:$Z$1,">="&$B2,$D$1:$Z$1,"<"&EDATE($B2,12))