Excel turns long numbers into scientific notation
If you work with 16-digit credit card numbers, long order IDs, or ISBNs in CSV files, you’ve seen this disaster: Excel displays them as 1.23E+15.
Even worse, if you try to fix the formatting by expanding the cell, you might see zeros at the end (e.g., 1234567890123450 instead of ...3456). The data has been corrupted.
The 15-Digit Limit
Excel follows the IEEE 754 standard for floating-point numbers, which only guarantees about 15 digits of precision. Any number longer than 15 digits gets truncated when stored as a number. The remaining digits are permanently lost and replaced with zeros.
How to prevent data loss
You must ensure these values are imported as Text, not Numbers.
Manual Method:
- Use Data > From Text/CSV.
- In the import preview, identify columns with long numbers.
- Explicitly set their type to Text before loading.
Warning: If you have already opened the file and saved it, the data is likely gone forever. You must go back to the original CSV source.
The Safe Solution
SterileCSV handles this automatically. It detects numeric strings that exceed Excel's precision limit and automatically flags them as text. This ensures that your 20-digit invoice ID remains exactly 20 digits long, without manual intervention.