Most problems after converting JSON to CSV appear when Excel opens the file, not during the conversion. Excel guesses the encoding, the delimiter and the type of every value, and each wrong guess shows up as garbled accents, values split across columns or missing zeros.
Here are the five most common symptoms, why they happen and how to fix them, with the settings the JSON to CSV converter already uses to prevent them.
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Key takeaways
- Garbled accents mean Excel read UTF-8 as another encoding; a byte-order mark prevents it.
- Values with commas, quotes or line breaks must be quoted to stay in one cell.
- Excel removes leading zeros and rounds numbers over 15 digits; keep such values as text.
- Converting straight to XLSX avoids Excel's guessing altogether.
Steps shown in the video
- Click Choose JSON Files and select your JSON file
- Your file is listed with its size
- Click Convert to CSV
- Download your .csv file
Problems and fixes at a glance
| Symptom | Cause | Fix |
|---|---|---|
| é instead of é | Encoding misread | Use UTF-8 with a byte-order mark |
| Text split across columns | Unquoted commas | Quote values that contain the delimiter |
| Everything in column A | Regional separator is a semicolon | Import with Data, From Text/CSV |
| 00123 shows as 123 | Excel reads codes as numbers | Store the value as a string, or use XLSX |
| Long ID shows as 1.23E+15 | Excel keeps 15 digits | Store the value as a string, or use XLSX |
Garbled accents and symbols
JSON is almost always UTF-8. A CSV saved as UTF-8 without a byte-order mark is often read by Excel as an older encoding, which turns é into é and € into €.
The converter writes a UTF-8 byte-order mark at the start of every CSV, so Excel detects the encoding correctly. If you created a CSV elsewhere, import it with Data, From Text/CSV and choose 65001: Unicode (UTF-8).
Values split across columns
A value such as "Lisbon, Portugal" contains a comma. Unless it is wrapped in quotes, a CSV reader treats the comma as a column break. Quotes inside values must also be doubled, and line breaks must be inside quotes, as described in RFC 4180.
name,address,note
Ana,"Lisbon, Portugal","She said ""call me"""The converter applies these rules automatically. If your whole file lands in column A instead, the issue is your regional list separator; see why a CSV opens in one column.
Missing zeros and rounded IDs
In JSON, "00123" is clearly a string. In a CSV it is just text, and Excel turns it into the number 123 when it opens the file. Numbers longer than 15 digits are rounded, because Excel stores numbers with 15 significant digits.
The CSV itself is correct; the change happens in Excel. Two reliable fixes:
- Import the CSV with Data, From Text/CSV, choose Transform Data and set those columns to Text.
- Skip CSV and convert the JSON directly to a workbook with JSON to Excel, where strings stay strings.
Rows broken by line breaks
Descriptions and addresses in JSON often contain \n line breaks. In the CSV they are kept inside quoted values, which Excel and Google Sheets handle correctly. Some simple import tools read line by line and break those rows apart. If your target system does that, replace line breaks with spaces in the JSON before converting.
A quick checklist before converting
- The JSON is valid: no trailing commas, single quotes or comments.
- IDs and codes are stored as strings in the JSON, not numbers.
- You know whether the file will be opened in Excel or imported by another system.
- For Excel, consider XLSX instead of CSV.
- For nested data, read how nested JSON becomes CSV.
JSON to CSV in Excel: FAQ
Why does my CSV show é instead of é?
The file is UTF-8 but was read with another encoding. A UTF-8 byte-order mark, which the converter adds, makes Excel read it correctly.
Why are my values split into extra columns?
They contain commas that were not quoted. Properly quoted values stay in one cell.
Why did Excel remove leading zeros from my IDs?
Excel converts number-like text to numbers when it opens a CSV. Import those columns as Text, or convert the JSON to XLSX instead.
Does the CSV keep line breaks inside values?
Yes, inside quoted values. Excel and Google Sheets read them correctly, but some basic import tools do not.
Is XLSX better than CSV for opening in Excel?
Usually. An XLSX file stores each value's type, so Excel does not need to guess.
Fix the guess, not the data
A correctly written CSV can still look wrong in Excel because Excel guesses while opening it. Use UTF-8 with a byte-order mark, quote special values, import IDs as text, or skip the guessing entirely with an XLSX file.
