Counting Excel Timestamps Between Two Times with Varying Time Values and Interval Ranges

In Excel, analyzing timestamps to count occurrences between specific time intervals is a common task in time-tracking and project management. This article walks you through how to count timestamps within specific time intervals, even when time values differ between timestamps and the interval range.

Basic Theory

In Excel, timestamps are stored as serial numbers with the integer portion representing the date and the decimal portion representing the time of day. To analyze timestamps based on specific time ranges, we can leverage Excel’s logical functions like COUNTIFS or SUMPRODUCT, which can evaluate if timestamps fall within designated intervals.

The Problem

Imagine you have a list of timestamps, each with a unique time value. You need to count how many of these timestamps fall within a specific time interval (e.g., between 9:00 AM and 5:00 PM). The challenge here is that each timestamp’s time component may vary, and we must count only the timestamps that meet the specified time conditions.

Scenario Setup

Let’s say we have the following list of timestamps in column A and we want to count how many fall between 9:00 AM and 5:00 PM.

Example Data Table

Solution

1. Define the Time Range for Counting
   We are interested in counting timestamps that fall between 9:00 AM and 5:00 PM.
   Start Time: 9:00 AM (0.375 in Excel time format)
   End Time: 5:00 PM (0.708333 in Excel time format)
2. Extract Time from Timestamps
   To check only the time component, we need to isolate it from the date-time value using Excel’s MOD function:

   =MOD(A2, 1)

   This formula extracts the decimal portion of the timestamp (the time part).

3. Use the COUNTIFS Function
   We can use COUNTIFS to count timestamps between the start and end times. Assuming our timestamps are in A2:A7, we can enter:

   =COUNTIFS(A2:A7, ">= " & DATE(2023,11,8)+9/24, A2:A7, "<= " & DATE(2023,11,8)+17/24)

   Here’s how it works:

   • The >= & DATE(2023,11,8)+9/24 checks if the time is after or equal to 9:00 AM.
   • The <= & DATE(2023,11,8)+17/24 ensures the time is before or equal to 5:00 PM.

Example Calculation

Following our example timestamps, we get:

In this scenario, we have 4 timestamps that meet the time range criteria.

Alternative Approaches

1. Using SUMPRODUCT
   An alternative is using SUMPRODUCT to create a conditional array formula. It allows you to count the values based on criteria without needing helper columns:

   =SUMPRODUCT(--(MOD(A2:A7, 1) >= 9/24), --(MOD(A2:A7, 1) <= 17/24))

   This formula works similarly but can be used in cases where COUNTIFS may not apply.

2. Array Formula with IF and MOD
   Another option is to use an array formula. Enter the following formula as an array formula (press Ctrl+Shift+Enter):

   =SUM(IF((MOD(A2:A7,1)>=9/24)*(MOD(A2:A7,1)<=17/24),1,0))

   This will yield the same result by evaluating each timestamp individually.

Summary Table

Counting timestamps within a specific time range in Excel requires understanding how to separate date and time components. The COUNTIFS, SUMPRODUCT, and array formulas provide flexible ways to tackle this task depending on your needs. Each approach can be applied based on the structure of your dataset, enabling effective time-based analysis in Excel.