## How to count overlapping time

The worksheet above shows four different time ranges in column B and C, the formula in cell C10 counts the number of overlapping minutes.

The formula uses the earliest and latest date and time value in column B and C as the range to count overlapping minutes.

Array formula in cell C10:

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.

### Explaining formula in cell C10

The INDEX function allows you to create an array of values, in this case, minute intervals.

MIN($B$3:$B$6)+(ROW(A1:INDEX($A:$A, (MAX($C$3:$C$6)-MIN($B$3:$B$6))*1440+1))-1)/1440

returns

{43101.25, 43101.2506944444, 43101.2513888889, 43101.2520833333, 43101.2527777778, 43101.2534722222, 43101.2541666667, 43101.2548611111, 43101.2555555556, 43101.25625, 43101.2569444444}

Now check if these minute intervals are between or equal to each date and time range.

(TRANSPOSE(MIN($B$3:$B$6)+(ROW(A1:INDEX($A:$A, (MAX($C$3:$C$6)-MIN($B$3:$B$6))*1440+1))-1)/1440)>=$B$3:$B$6)*((TRANSPOSE(MIN($B$3:$B$6)+(ROW(A1:INDEX($A:$A, (MAX($C$3:$C$6)-MIN($B$3:$B$6))*1440+1))-1)/1440))<$C$3:$C$6)

returns

{1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0; 0, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0; 0, 0, 1, 1, 1, 1, 1, 1, 0, 0, 0; 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0}

The MMULT function allows you to add these values column by column.

MMULT(TRANSPOSE($B$3:$B$6^0), (TRANSPOSE(MIN($B$3:$B$6)+(ROW(A1:INDEX($A:$A, (MAX($C$3:$C$6)-MIN($B$3:$B$6))*1440+1))-1)/1440)>=$B$3:$B$6)*((TRANSPOSE(MIN($B$3:$B$6)+(ROW(A1:INDEX($A:$A, (MAX($C$3:$C$6)-MIN($B$3:$B$6))*1440+1))-1)/1440))<$C$3:$C$6))

becomes

MMULT(TRANSPOSE($B$3:$B$6^0), {1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0; 0, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0; 0, 0, 1, 1, 1, 1, 1, 1, 0, 0, 0; 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0})

becomes

MMULT({1,1,1,1}, {1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0; 0, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0; 0, 0, 1, 1, 1, 1, 1, 1, 0, 0, 0; 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0})

and returns

{1, 2, 3, 3, 2, 2, 2, 2, 1, 2, 0}

The following picture shows the array and what the MMULT function returns.

A value larger than 1 indicates an overlapping time value.

MMULT(TRANSPOSE($B$3:$B$6^0), (TRANSPOSE(MIN($B$3:$B$6)+(ROW(A1:INDEX($A:$A, (MAX($C$3:$C$6)-MIN($B$3:$B$6))*1440+1))-1)/1440)>=$B$3:$B$6)*((TRANSPOSE(MIN($B$3:$B$6)+(ROW(A1:INDEX($A:$A, (MAX($C$3:$C$6)-MIN($B$3:$B$6))*1440+1))-1)/1440))<=$C$3:$C$6))>1

becomes

{1, 2, 3, 3, 2, 2, 2, 2, 1, 2, 0}>1

and returns

{FALSE, TRUE, TRUE, TRUE, TRUE, TRUE, TRUE, TRUE, FALSE, TRUE, FALSE}.

Lastly, multiply with 1 to convert boolean values to numerical values and then sum the numbers.

SUM((MMULT(TRANSPOSE($B$3:$B$6^0), (TRANSPOSE(MIN($B$3:$B$6)+(ROW(A1:INDEX($A:$A, (MAX($C$3:$C$6)-MIN($B$3:$B$6))*1440+1))-1)/1440)>=$B$3:$B$6)*((TRANSPOSE(MIN($B$3:$B$6)+(ROW(A1:INDEX($A:$A, (MAX($C$3:$C$6)-MIN($B$3:$B$6))*1440+1))-1)/1440))<=$C$3:$C$6))>1)*1)

becomes

SUM({FALSE, TRUE, TRUE, TRUE, TRUE, TRUE, TRUE, TRUE, FALSE, TRUE, FALSE}*1)

becomes

SUM({0,1,1,1,1,1,1,1,0,1,0})

and returns 8.

The picture above shows you a different setup, it allows you to use a smaller range than the min and max date and time in B3:C5.

Formula in cell C14:

The ROW function limits the use of these formulas, if you have a range larger than 1,048,576 minutes, which is the same as the number of rows in a worksheet, you will need another solution than the one presented here.

### Download Excel *.xlsx file

Count unique distinct values that meet multiple criteria

This post demonstrates how to build an array formula that counts unique distinct values based on criteria. What's on this […]

This article describes how to count unique distinct values. What are unique distinct values? They are all values but duplicates are […]

Count Conditionally Formatted cells

This article explains how to count cells highlighted with Conditional Formatting (CF). The image above shows data in cell range […]

Count cells between specified values

This article demonstrates formulas that calculate the number of cells between two values, the first scenario involves two search values […]

Count unique distinct values in two columns

Formula in C12: =SUM(1/COUNTIF($B$3:$B$8, $B$3:$B$8))+SUM(IF(COUNTIF($B$3:$B$8, $D$3:$D$8)=0, 1/COUNTIF($D$3:$D$8, $D$3:$D$8), 0)) How to create an array formula Double click on cell C12 […]

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, […]

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 […]

Identify rows of overlapping records

cwrbelis asks: Hi Oscar, Great website! Keep up the good work. I have a question as to how to expand […]

### 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