Lesson 1.4 – Data Types in Excel: Text, Numbers, and Dates

Excel interprets data differently depending on its type. Understanding how Excel classifies text, numbers, and dates is essential for accurate calculations, sorting, filtering, and data analysis. This lesson explains how each data type works and how Excel behaves when processing them.

---

1. Text (Strings)

Text is any content that Excel does not recognize as a number or date. Text is aligned to the left by default. It is commonly used for labels, names, categories, and descriptive information.

Examples of text:

• Product A
• January
• Invoice #4521
• ABC123

Even numeric-looking values may be treated as text if they contain leading zeros, spaces, or non-numeric characters.

---

2. Numbers

Numbers are values Excel can use in calculations. They are aligned to the right by default. Numbers can represent quantities, prices, percentages, measurements, or any numeric data.

Examples of numbers:

• 150
• 3.75
• -20
• 12000

Excel automatically recognizes numbers unless the entry contains symbols, spaces, or formatting that prevents interpretation.

---

3. Dates and Times

Dates and times are stored as numeric values in Excel. This allows Excel to perform calculations such as differences between dates, sorting by date, and generating timelines.

A date appears in a readable format (e.g., 12/03/2024), but internally Excel stores it as a serial number. For example:

• 1 = January 1, 1900
• 45000 ≈ a date in 2023

Times are stored as decimal fractions of a day:

• 0.5 = 12:00 (noon)
• 0.25 = 06:00

Dates and times are right-aligned by default. If a date appears left-aligned, Excel is treating it as text.

---

4. How Excel Determines the Data Type

Excel automatically assigns a data type based on the content entered. The following rules apply:

• If the entry contains only digits → Excel interprets it as a number.
• If the entry matches a date pattern → Excel interprets it as a date.
• If the entry contains letters or symbols → Excel interprets it as text.
• If the entry begins with an apostrophe (') → Excel forces text format.

---

5. Common Issues with Data Types

Incorrect data types often cause calculation errors. Common issues include:

• Numbers stored as text (cannot be summed)
• Dates stored as text (cannot be sorted chronologically)
• Text that looks like a number (e.g., product codes)
• Imported data with inconsistent formatting

---

6. Practical Exercise

Practice identifying and working with data types:

1. Create a worksheet named Lesson_1_4_Practice.
2. In column A, enter five text values.
3. In column B, enter five numeric values.
4. In column C, enter five dates in DD/MM/YYYY format.
5. Check alignment: text left, numbers and dates right.
6. Enter '123 and observe that Excel treats it as text.

---

Next Lesson

Lesson 2.1 – Entering Data