How to Make Excel Cells Change Color Automatically Based on Date and Time?

You can automatically change Excel cell colors based on date and time using Conditional Formatting with formulas.

Making your Excel sheets visually dynamic based on real-time data like dates and times helps you quickly identify crucial information, such as approaching deadlines, overdue tasks, or upcoming events. The most common and powerful way to achieve this is through Conditional Formatting using custom formulas.

This method allows you to set specific rules where if a formula evaluates to TRUE for a cell, that cell (or another cell) will be formatted in a way you define (e.g., fill color, font color, border).

Step-by-Step Guide to Conditional Formatting Based on Date/Time

Follow these steps to set up automatic cell coloring based on dates and times in your Excel sheet:

1. Select the Range: First, select the cells or the entire range you want to apply the conditional formatting to. This is typically the cells containing the dates or times you want to monitor, or entire rows if you want the whole row to change color based on a date/time in one specific column. As shown in the reference, you might start by selecting the first row of your data (or the entire column containing the dates/times), then apply the rule, and finally use the Format Painter or manage rules to apply it to the rest of your data.
2. Access Conditional Formatting: Go to the Home tab on the Excel ribbon. In the "Styles" group, click on Conditional Formatting.
3. Create a New Rule: From the dropdown menu, select New Rule.... This opens the "New Formatting Rule" dialog box.
4. Choose Rule Type: In the "Select a Rule Type:" box, select the last option: "Use a formula to determine which cells to format". This is the approach highlighted in the provided reference.
5. Enter the Formula: In the "Format values where this formula is true:" box, enter the formula that will check the date or time condition. The formula should refer to the first cell in your selected range that contains the date or time you're evaluating. Use relative and absolute references carefully (e.g., $A1 to apply to column A but check row by row, or A1 if applying only to cell A1).
6. Set the Formatting: Click the Format... button. This opens the "Format Cells" dialog box. Go to the Fill tab to choose a background color, the Font tab to change text style or color, or the Border tab to add borders. Select your desired formatting and click OK.
7. Apply and Confirm: Back in the "New Formatting Rule" dialog box, click OK. Your conditional formatting rule is now applied to the selected range.

Useful Formulas for Date and Time Conditions

Here are some common formulas you can use in Step 5, assuming your date or time is in cell A1 of the first row of your selected range:

• Highlight if Past Due (Based on Date):
  =A1<TODAY()
  • This formula will be TRUE if the date in cell A1 is earlier than the current date. TODAY() is an Excel function that returns the current date (without time).
• Highlight if Due Today (Based on Date):
  =A1=TODAY()
  • This formula is TRUE if the date in cell A1 is exactly the current date.
• Highlight if Due Within Next 7 Days (Based on Date):
  =AND(A1>=TODAY(), A1<=TODAY()+7)
  • This formula uses AND to check if the date in A1 is today or later (>=TODAY()) AND also within the next 7 days (<=TODAY()+7).
• Highlight if Past Due (Based on Date and Time):
  =A1<NOW()
  • This formula is TRUE if the date and time in cell A1 is earlier than the current date and time. NOW() returns the current date and time. Note that using NOW() might require your spreadsheet to recalculate to update colors dynamically.
• Highlight if in the Future (Based on Date):
  =A1>TODAY()
  • This is TRUE if the date in A1 is after today's date.

Tip: If you want the entire row to change color based on the date in column A, select the range covering all the columns you want to format (e.g., A1:Z100), and use a formula like =$A1<TODAY(). The $ before A makes the column reference absolute, ensuring that for every row, the formula always checks the date in column A of that same row.

Managing Your Rules

You can manage, edit, delete, or reorder your conditional formatting rules by going back to Conditional Formatting > Manage Rules.... This is especially useful if you have multiple rules applied to the same range, as the order determines which rule takes precedence if multiple rules are TRUE for a cell.

By using conditional formatting with formulas, your Excel cells can provide instant visual cues about the status of your date and time-sensitive data.