CSV guide

Find missing values in a CSV

Unwrap counts empty cells and can flag values that may also mean “missing.”

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Missing does not always look empty

Consider this small customer export:

customer_id,age,region
1001,34,DE
1002,,AT
1003,-1,N/A

The empty age is clearly missing. But -1 may also mean that the age was unknown, and N/A may mean that no region was recorded. Only someone who knows the source data can confirm that.

Unwrap reports empty cells separately from values that look like missing-value codes.

What you can check

What to check first

1. Start with important columns. Missing customer IDs, dates, or amounts usually matter more than gaps in an optional note.
2. Compare empty and missing-like values. A column may use more than one way to record the same absence.
3. Check the original rows. The surrounding values can help you understand what a placeholder means.
4. Confirm the rule at the source. Do not replace 0, -1, or N/A until you know what the exporting system intended.

Why placeholder values matter

A blank cell is often left out of calculations. A number such as -1 is not: it can lower an average or become the smallest value in a range. Text such as N/A can also make a number column appear to contain text.

Finding these values early helps you decide what to clean before using the CSV elsewhere.

Check the counts you are using

If the dataset is marked Sample, missing-value counts cover only the loaded rows. Select Load full file for complete counts. Possible placeholders still need your interpretation: -1 might mean “unknown” in one export and a real value in another.

Common questions

Does zero count as missing?

Not automatically. Zero is often a valid value. Unwrap only flags it in limited cases where the column and its other values make it look unusual.

What about cells that contain only spaces?

They may look blank while still containing text. Unwrap can include empty-looking strings among the possible missing-value codes.

Does Unwrap check every row?

It checks every loaded row. If you see the Sample label, select Load full file when you need counts for the complete CSV.

Continue exploring

• CSV column analyzer — see all available details for a column
• Fix broken CSV — understand rows that do not line up
• CSV viewer — compare the available views