# AutoFill

Course: [Excel](https://www.devtutorials.ai/learn/excel) · Section: Formulas and Functions
Source: https://www.devtutorials.ai/learn/excel/formulas-and-functions/autofill

> Fill number series, copy patterns, create date series, and use AutoFill Options with the fill handle.

Entering long lists of numbers, dates, or repeating patterns manually can take time and increase the chance of mistakes. **AutoFill** helps by continuing a pattern for you automatically. Simply enter the starting values, drag the fill handle, and Excel fills the remaining cells. In this lesson, you'll learn how to create number series, copy patterns, fill date sequences, and use AutoFill options.

Open the **Excel sandbox** and follow along.

## The Fill Handle

When you select a cell, a small square appears in the **bottom-right corner** of the selection. This square is called the **fill handle**.

When you position the pointer over the fill handle, it changes into a thin black **+**.

You can use the fill handle to:

- Drag down or across to fill adjacent cells.
- Double-click to automatically fill down alongside existing data.

## Fill Series

A **series** is a sequence of values that follows a pattern.

To create a number series:

1. Enter the first two values.
2. Select both cells.
3. Drag the fill handle.

Examples:

| Starting Values | AutoFill Result |
|----------|----------|
| `1, 2` | `3, 4, 5, 6...` |
| `5, 10` | `15, 20, 25, 30...` |
| `100, 90` | `80, 70, 60, 50...` |

Excel analyzes the difference between the starting values and continues the pattern automatically.

To create a number sequence, enter **two values** whenever possible. If only one number is selected, Excel will usually copy that number instead of continuing a series.

## Copy Patterns

AutoFill can recognize and continue many common text patterns.

| Starting Value | AutoFill Continues As |
|----------|----------|
| `Mon` | `Tue`, `Wed`, `Thu`... |
| `January` | `February`, `March`, `April`... |
| `Q1` | `Q2`, `Q3`, `Q4`... |
| `Item 1` | `Item 2`, `Item 3`, `Item 4`... |
| `Yes` | `Yes`, `Yes`, `Yes`... |

Excel copies ordinary text values unless it recognizes a built-in pattern such as days, months, quarters, or numbered text.

AutoFill can also copy formulas while automatically adjusting relative references.

## Date Series

AutoFill works with dates as well as numbers.

If you enter a single date and drag the fill handle, Excel generates sequential dates.

Example:

```text
1/1/2026
1/2/2026
1/3/2026
1/4/2026
```

To create a custom interval, enter two dates before dragging.

Examples:

| Starting Dates | AutoFill Result |
|----------|----------|
| `1/1/2026`, `1/8/2026` | Weekly dates |
| `1/1/2026`, `2/1/2026` | Monthly dates |

AutoFill can only continue dates that Excel recognizes as actual date values. If the value is stored as text, Excel copies it instead of generating a date sequence.

## AutoFill Options

After using AutoFill, an **AutoFill Options** button appears near the filled cells.

Select it to choose how Excel handles the fill operation.

| Option | Description |
|----------|----------|
| **Copy Cells** | Copies the original value instead of continuing a pattern |
| **Fill Series** | Continues the detected series |
| **Fill Formatting Only** | Copies formatting without values |
| **Fill Without Formatting** | Copies values without formatting |
| **Fill Days** | Continues a daily date sequence |
| **Fill Weekdays** | Continues dates while skipping weekends |
| **Fill Months** | Continues by month |
| **Fill Years** | Continues by year |

If AutoFill produces the opposite result from what you expected, use the **AutoFill Options** button to switch between copying and filling a series.

## Common mistakes

| Mistake | Result | Solution |
|----------|----------|----------|
| Filling from a single number | The value is copied repeatedly | Enter and select two starting values |
| Dragging the cell border instead of the fill handle | The cells are moved | Undo and drag the fill handle |
| Expecting ordinary text to continue automatically | The text is copied | Use recognized patterns such as months or numbered text |
| Filling beyond the required range | Extra values appear | Undo and fill only to the required location |
| Copying formulas without locking required references | Formulas return incorrect results | Use absolute references where needed |

## Exercise

Click **Reset** in the sandbox header. Then complete the following tasks and click **Check**.

## What to Remember

- The **fill handle** is the small square in the bottom-right corner of a selected cell.
- Enter **two values** to define the pattern of a number series.
- AutoFill can continue days, months, quarters, dates, and numbered text.
- A single date creates a daily sequence, while two dates define a custom interval.
- Use **AutoFill Options** to switch between copying values and filling a series.
- Double-click the fill handle to fill down alongside existing data.
- AutoFill is useful for both values and formulas.

In the next lesson, you'll learn how to use Excel's most commonly used functions: **SUM**, **AVERAGE**, **MIN**, **MAX**, and **COUNT**.