Filling Series and Patterns

The fill handle copies formulas, but it can also generate series and patterns of plain values. Dates, numbers, weekdays, and months can all be filled automatically.

This means you rarely have to type a sequence by hand. Type the start, give the spreadsheet a hint about the pattern, then drag, and it continues the series for you.

Type 1 in A1 and 2 in A2. Select both cells, then drag the fill handle down.

The spreadsheet sees the step of +1 and continues: 3, 4, 5, 6, and so on. The two starting cells tell it the gap between values.

Try 5 and 10 instead and you get 15, 20, 25. The pattern is whatever difference your two seed cells establish.

The number of seed cells changes the result.

• One cell with the number 1, dragged down, often just copies 1, 1, 1. In Excel hold Ctrl while dragging to count up instead.
• Two cells establish a step, so 1 and 2 fill as 3, 4, 5 with no extra keys.

When in doubt, seed two cells. It removes all ambiguity about the pattern you want.

Dates are a natural series. Type a date like 01/01/2026 in A1, then drag the fill handle down.

The spreadsheet advances one day at a time: Jan 2, Jan 3, Jan 4. With dates you only need a single seed cell because the default step is one day.

This is perfect for building a calendar column, a daily log, or a schedule without typing every date.

The fill handle recognizes named sequences too. Type Monday and drag down to get Tuesday, Wednesday, Thursday, and so on.

Type January and drag to get February, March, April. Short forms work as well: Mon fills as Tue, Wed; Jan fills as Feb, Mar.

These built-in lists save real time when labeling reports by day or month.

You are not stuck with one-day steps. Type 01/01/2026 in A1 and 08/01/2026 in A2, select both, and drag.

The spreadsheet detects a 7-day gap and fills every seventh day, giving you weekly dates. Seed two dates a month apart and it fills monthly. Two seed cells define any custom interval you like.

Text with a trailing number is treated as a pattern. Type Item 1 and drag down to get Item 2, Item 3, Item 4.

This is handy for invoice lines, ticket numbers, or labels like Q1 filling to Q2, Q3, Q4. The spreadsheet keeps the text and counts up the numeric part automatically.

Right after you drag in Excel, a small Auto Fill Options button appears near the end of the filled range. Click it to choose what happened.

Options include Copy Cells, Fill Series, Fill Days, and Fill Without Formatting. If a drag copied when you wanted a series, switch it here without redoing the drag. It is your undo-and-adjust shortcut.

Excel's Flash Fill spots patterns from your examples. If column A holds full names and you type the first name in B2, Excel can fill the rest of the first names automatically.

Type one or two examples, then press Ctrl+E. Excel detects the pattern, in this case "take the text before the space," and fills the column. It is pattern recognition without a formula.

Modern Excel and Google Sheets offer a formula way to build number series: the SEQUENCE function. It spills a list of numbers from one formula.

The formula =SEQUENCE(10) produces the numbers 1 through 10 down a column. Unlike a dragged series, it updates automatically if you change the count. You will explore SEQUENCE fully in a later array course.

Google Sheets often shows an autofill suggestion automatically. Start a recognizable list, such as a few dates or names, and Sheets may display a faint preview of the continued series.

Press Ctrl+Enter or click the checkmark to accept the suggestion. It is Sheets' equivalent of Excel's Flash Fill, predicting your pattern as you type.

Test your grasp of filling series.

You can now auto-generate data, not just copy formulas:

• Seed two cells to define a number step, then drag to continue it.
• Dates, weekdays, and months fill as recognized series.
• The Auto Fill Options button switches between copy and series after a drag.
• Flash Fill (Ctrl+E) and Sheets suggestions extract patterns from your examples.

Next you will learn to spot and fix formulas that break when copied.