Sum columns based on multiple criteria

[Delaney21]

[TABLE="width: 500"]
<tbody>[TR]
[TD]Date Sold[/TD]
[TD]Aug-17[/TD]
[TD]Sep-17[/TD]
[TD]Oct-17[/TD]
[TD]Nov-17[/TD]
[TD]Dec-17[/TD]
[TD]Jan-18[/TD]
[TD]Feb-18[/TD]
[TD]Mar-18[/TD]
[TD]Apr-18[/TD]
[/TR]
[TR]
[TD]1/31/16[/TD]
[TD]20[/TD]
[TD]20[/TD]
[TD]20[/TD]
[TD]20[/TD]
[TD]20[/TD]
[TD]20[/TD]
[TD]20[/TD]
[TD]20[/TD]
[TD]20[/TD]
[/TR]
[TR]
[TD]6/25/17[/TD]
[TD]18[/TD]
[TD]18[/TD]
[TD]18[/TD]
[TD]18[/TD]
[TD]18[/TD]
[TD]18[/TD]
[TD]18[/TD]
[TD]18[/TD]
[TD]18[/TD]
[/TR]
[TR]
[TD]1/5/18[/TD]
[TD]19[/TD]
[TD]19[/TD]
[TD]19[/TD]
[TD]19[/TD]
[TD]19[/TD]
[TD]19[/TD]
[TD]19[/TD]
[TD]19[/TD]
[TD]19[/TD]
[/TR]
[TR]
[TD]4/23/17[/TD]
[TD]21[/TD]
[TD]21[/TD]
[TD]21[/TD]
[TD]21[/TD]
[TD]21[/TD]
[TD]21[/TD]
[TD]21[/TD]
[TD]21[/TD]
[TD]21[/TD]
[/TR]
[TR]
[TD]8/16/17[/TD]
[TD]17[/TD]
[TD]17[/TD]
[TD]17[/TD]
[TD]17[/TD]
[TD]17[/TD]
[TD]17[/TD]
[TD]17[/TD]
[TD]17[/TD]
[TD]17[/TD]
[/TR]
</tbody>[/TABLE]

I'm trying to figure out a formula that will look at the date sold column and only pull dates before 1/1/18 and then I need it to sum Aug-17 to a specific date - this date will change on a frequent basis, so I was going to put that end date in a separate cell that I could reference.

For this example, I need it to start the sum at Aug-17 (which will never change), to Dec-17 (end date will change frequently). I've colored the numbers I want it to sum in red.
Will someone please help me with a formula to do this?

Thank you!!

 

[VBA Geek]

Excel 2010
	A	B	C	D	E	F	G	H	I	J	K	L	M	N
1	Date Sold	1-Aug	1-Sep	1-Oct	1-Nov	1-Dec	1-Jan	1-Feb	1-Mar	1-Apr
2	1/31/2016	20	20	20	20	20	20	20	20	20			date column Before	1/1/2018
3	6/25/2017	18	18	18	18	18	18	18	18	18			sum until	12/1/2017
4	1/5/2018	19	19	19	19	19	19	19	19	19
5	4/23/2017	21	21	21	21	21	21	21	21	21
6	8/16/2017	17	17	17	17	17	17	17	17	17			380
7
Sheet3

Cell Formulas
Range	Formula
M6	{=SUMPRODUCT(MMULT(TRANSPOSE(B2:J6),--(N2>A2:A6)),TRANSPOSE(--(B1:J1<=N3)))}
Press CTRL+SHIFT+ENTER to enter array formulas.

 

[sheetspread]

Excel 2010
	A	B	C	D	E	F	G	H	I	J
1	Date Sold	Aug-17	Sep-17	Oct-17	Nov-17	Dec-17	Jan-18	Feb-18	Mar-18	Apr-18
2	1/31/2016	20	20	20	20	20	20	20	20	20
3	6/25/2017	18	18	18	18	18	18	18	18	18
4	1/5/2018	19	19	19	19	19	19	19	19	19
5	4/23/2017	21	21	21	21	21	21	21	21	21
6	8/16/2017	17	17	17	17	17	17	17	17	17
7
8
9		380
Sheet3

Cell Formulas
Range	Formula
B9	=SUMPRODUCT(($A$2:$A$6<43101)*($B$1:$J$1<43101)*$B$2:$J$6)

 

[Delaney21]

This is awesome!!! Thank you so much!!