Check a CSV dataset for missing values: count and percentage per variable, complete cases and incomplete rows, with custom missing codes like -99.
About this tool
Count and chart missing values per variable and find incomplete rows in a dataset.
How to use Missing Data Checker
- Upload or paste your dataset.
- Add any codes your data uses for missing values, such as -99 or 999.
- Sort variables by missingness and download the report.
Worked example
In a 16-row dataset, BMI is missing for 2 people (12.5%) and only 12 rows (75%) are complete cases.
What counts as missing?
Blank cells always count. By default NA, N/A, NaN, null, None, “.”, “-”, “?” and #N/A count too, and you can edit the list.
How much missing data is too much?
There is no fixed cut-off, but more than 5–10% on a key variable deserves attention and possibly multiple imputation.
- Missing Data Checker — Count and chart missing values per variable and find incomplete rows in a dataset.
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