## Filter overlapping date ranges

This blog article describes how to extract coinciding date ranges using array formulas, the image above shows random date ranges in cell range B3:C25.

**Overlapping date ranges**

Array formula in cell E4:

To enter an array formula, type the formula in a cell then press and hold CTRL + SHIFT simultaneously, now press Enter once. Release all keys.

The formula bar now shows the formula with a beginning and ending curly bracket telling you that you entered the formula successfully. Don't enter the curly brackets yourself.

Copy cell E4 and paste down as far as needed.

Array formula in cell F4:

Copy cell F4 and paste down as far as needed.

**Date ranges without overlapping**

Array formula in cell E17:

Copy cell E17 and paste down as far as needed.

Array formula in cell F17:

Copy cell F17 and paste down as far as needed.

### Explaining array formula in cell E4

=SMALL(IF(COUNTIFS($B$3:$B$25, "<="&$C$3:$C$25, $C$3:$C$25, ">="&$B$3:$B$25)>1, $B$3:$B$25, ""), ROW(A1))

*Step 1 - Find overlapping date ranges*

The COUNTIFS function calculates the number of cells across multiple ranges that equals all given conditions.

=SMALL(IF(**COUNTIFS($B$3:$B$25, "<="&$C$3:$C$25, $C$3:$C$25, ">="&$B$3:$B$25)>1**, $B$3:$B$25, ""), ROW(A1))

COUNTIFS($B$3:$B$25, "<="&$C$3:$C$25, $C$3:$C$25, ">="&$B$3:$B$25)

becomes

COUNTIFS({40109;40171;40210; 40264;40397;40405;40417;40457; 40500;40545;40611;40617;40726;40777;40791;40802;40831;40882;40994; 41014;41040;41127;41182}, "<="&{40137;40188;40268;40264;40401; 40413;40447;40517;40503; 40608;40613;40710;40773;40791;40817;40812;40875; 40927;41010;41085;41086;41168;41262}, ${40137;40188;40268;40264;40401; 40413;40447;40517;40503; 40608;40613;40710;40773;40791;40817;40812;40875;40927; 41010;41085;41086;41168;41262}, ">="&${40109;40171;40210;40264;40397;40405; 40417;40457; 40500;40545;40611;40617;40726;40777;40791;40802;40831;40882;40994; 41014;41040;41127;41182}) and returns {1;1;2;2;1;1;1;2;2;1;1;1;1;2;3;2;1;1;1;2;2;1;1}

COUNTIFS($B$3:$B$25, "<="&$C$3:$C$25, $C$3:$C$25, ">="&$B$3:$B$25)>1

returns

{FALSE;FALSE;TRUE; TRUE;FALSE;FALSE;FALSE;TRUE;TRUE;FALSE; FALSE;FALSE;FALSE;TRUE;TRUE;TRUE;FALSE;FALSE; FALSE;TRUE;TRUE;FALSE;FALSE}

*Step 2 - Convert boolean array to start dates*

The IF function has three arguments, the first one must be a logical expression. If the expression evaluates to TRUE then one thing happens (argument 2) and if FALSE another thing happens (argument 3).

=SMALL(**IF(COUNTIFS($B$3:$B$25, "<="&$C$3:$C$25, $C$3:$C$25, ">="&$B$3:$B$25)>1, $B$3:$B$25, "")**, ROW(A1))

IF(COUNTIFS($B$3:$B$25, "<="&$C$3:$C$25, $C$3:$C$25, ">="&$B$3:$B$25)>1, $B$3:$B$25, "")

becomes

IF({FALSE;FALSE;TRUE;TRUE; FALSE;FALSE;FALSE;TRUE;TRUE;FALSE; FALSE;FALSE;FALSE;TRUE;TRUE;TRUE;FALSE;FALSE; FALSE;TRUE;TRUE;FALSE;FALSE}, {40109;40171;40210; 40264;40397;40405;40417;40457;40500; 40545;40611;40617;40726;40777;40791;40802;40831;40882; 40994;41014;41040;41127;41182}, "")

and returns

{"";"";40210;40264; "";"";"";40457;40500;"";""; "";"";40777;40791;40802;"";"";""; 41014;41040;"";""}

*Step 3 - Return the k-th smallest number in array*

To be able to return a new value in a cell each I use the SMALL function to filter column numbers from smallest to largest.

The ROW function keeps track of the numbers based on a relative cell reference. It will change as the formula is copied to the cells below.

SMALL(array,k) returns the k-th smallest number in this data set.

=SMALL(IF(COUNTIFS($B$3:$B$25, "<="&$C$3:$C$25, $C$3:$C$25, ">="&$B$3:$B$25)>1, $B$3:$B$25, ""), ROW(A1))

becomes

=SMALL({"";"";40210;40264;"";""; "";40457;40500;"";"";"";"";40777;40791;40802;"";"";"";41014; 41040;"";""}, ROW(A1))

becomes

=SMALL({"";"";40210;40264;"";""; "";40457;40500;"";"";"";"";40777;40791;40802;"";"";""; 41014;41040;"";""}, 1) and returns 40210 (1-Feb-2010)

Identify overlapping date ranges

The formula in cell F6 returns TRUE if the date range on the same row overlaps another date range in […]

Highlight records based on overlapping date ranges and a condition

adam asks: Hi, I have a situation where I want to count if this value is duplicate and if it […]

How to calculate overlapping time ranges

I found an old post that I think is interesting to write about today. Think of two overlapping ranges, it may be dates, […]

Identify rows of overlapping records

This article demonstrates a formula that points out row numbers of records that overlap the current record based on a […]

Count overlapping days in multiple date ranges

The MEDIAN function lets you count overlapping dates between two date ranges. If you have more than two date ranges […]

Count overlapping days across multiple date ranges

This post demonstrates a formula in cell D16 that counts overlapping dates across multiple date ranges. The date ranges are […]

Count overlapping days in multiple date ranges, part 2

In the previous post I explained how to count overlapping dates between a single date range and multiple date ranges. In […]

Find missing dates in a set of date ranges

The formula in cell B8, shown above, extracts dates not included in the date ranges, in other words, dates that […]

Highlight date ranges overlapping selected record [VBA]

This article demonstrates event code combined with Conditional Formatting that highlights overlapping date ranges based on the selected date range. […]

Working with overlapping date ranges

Today's blog post is about date ranges, the techniques demonstrated here can also be applied to time or other numerical […]

### One Response to “Filter overlapping date ranges”

### Leave a Reply

### How to comment

**How to add a formula to your comment**

<code>Insert your formula here.</code>

**Convert less than and larger than signs**

Use html character entities instead of less than and larger than signs.

< becomes < and > becomes >

**How to add VBA code to your comment**

[vb 1="vbnet" language=","]

Put your VBA code here.

[/vb]

**How to add a picture to your comment:**

Upload picture to postimage.org or imgur

Paste image link to your comment.

**Contact Oscar**

You can contact me through this contact form

[…] Here is a post where I use comparison operators: Filter overlapping date ranges […]