# Sequential numbering based on information in another column

Options
edited 02/15/24

I'm trying to create a formula (preferably one that can be converted into a column formula) that will generate a sequential Change Order Number based on the position and number of times the Contract # is used in my sheet. I'm attaching a screenshot of what I need the finished product to look like. I'm sure I will need an auto number row in here somewhere and probably a helper column but this one's got me scratching my head.

Thanks for any help!

Tags:

## Best Answer

• ✭✭✭✭✭
edited 02/14/24 Answer ✓
Options
```="CO-0" + COUNTIF([Contact #]\$1:[Contact #]2, [Contact #]@row) + "-" + [Contact #]@row
```

Some notes:

1. You need to drag the formula from top. Start of range is anchored to Row 1, and End of range is range at row.
2. The serial CO-0 will need a bit of tweaking to count with leading zeroes.

Here's with the flexible leading zeroes up to 999

```="CO-" +
IF(COUNTIF([Contact #]\$1:[Contact #]1, [Contact #]@row) < 10, "00",
IF(COUNTIF([Contact #]\$1:[Contact #]1, [Contact #]@row) < 99, "0", "")) +
COUNTIF([Contact #]\$1:[Contact #]1, [Contact #]@row) +
"-" + [Contact #]@row
```

...

## Answers

• ✭✭✭✭✭
edited 02/14/24 Answer ✓
Options
```="CO-0" + COUNTIF([Contact #]\$1:[Contact #]2, [Contact #]@row) + "-" + [Contact #]@row
```

Some notes:

1. You need to drag the formula from top. Start of range is anchored to Row 1, and End of range is range at row.
2. The serial CO-0 will need a bit of tweaking to count with leading zeroes.

Here's with the flexible leading zeroes up to 999

```="CO-" +
IF(COUNTIF([Contact #]\$1:[Contact #]1, [Contact #]@row) < 10, "00",
IF(COUNTIF([Contact #]\$1:[Contact #]1, [Contact #]@row) < 99, "0", "")) +
COUNTIF([Contact #]\$1:[Contact #]1, [Contact #]@row) +
"-" + [Contact #]@row
```

...

## Help Article Resources

Want to practice working with formulas directly in Smartsheet?

Check out the Formula Handbook template!