PowerShell Script to Convert CSV to JSON Easily

Use Import-Csv 'input.csv' | ConvertTo-Json | Set-Content 'output.json' in PowerShell to convert a CSV file to JSON format quickly.

Examples

InputName,Age Alice,30 Bob,25

Output[ { "Name": "Alice", "Age": "30" }, { "Name": "Bob", "Age": "25" } ]

InputProduct,Price,Stock Pen,1.5,100 Notebook,3.0,200

Output[ { "Product": "Pen", "Price": "1.5", "Stock": "100" }, { "Product": "Notebook", "Price": "3.0", "Stock": "200" } ]

InputCity,Population New York,8419000 Los Angeles,3980000 Chicago,2716000

Output[ { "City": "New York", "Population": "8419000" }, { "City": "Los Angeles", "Population": "3980000" }, { "City": "Chicago", "Population": "2716000" } ]

How to Think About It

To convert CSV to JSON in PowerShell, first read the CSV file using Import-Csv which converts each row into an object. Then use ConvertTo-Json to transform these objects into JSON format. Finally, save the JSON string to a file with Set-Content.

Algorithm

1

Read the CSV file using Import-Csv to get objects.

2

Convert the objects to JSON format using ConvertTo-Json.

3

Write the JSON string to an output file using Set-Content.

Code

powershell

Import-Csv 'input.csv' | ConvertTo-Json | Set-Content 'output.json'

# To see the JSON output on screen:
Import-Csv 'input.csv' | ConvertTo-Json | Write-Output

Output

[
  {
    "Name": "Alice",
    "Age": "30"
  },
  {
    "Name": "Bob",
    "Age": "25"
  }
]

Dry Run

Let's trace converting a CSV with two rows: Name,Age\nAlice,30\nBob,25 through the code.

1

Import CSV

Import-Csv reads the CSV and creates an array of objects: [{Name: 'Alice', Age: '30'}, {Name: 'Bob', Age: '25'}]

2

Convert to JSON

ConvertTo-Json converts the array of objects into a JSON string representing the array.

3

Write JSON to file

Set-Content writes the JSON string to 'output.json' file.

Step	Data
Import-Csv	[{Name: 'Alice', Age: '30'}, {Name: 'Bob', Age: '25'}]
ConvertTo-Json	[{"Name":"Alice","Age":"30"},{"Name":"Bob","Age":"25"}]
Set-Content	Writes JSON string to output.json

Why This Works

Step 1: Import-Csv reads CSV

The Import-Csv cmdlet reads the CSV file and converts each row into a PowerShell object with properties matching the CSV headers.

Step 2: ConvertTo-Json transforms objects

ConvertTo-Json takes the array of objects and converts it into a JSON formatted string representing the data.

Step 3: Set-Content saves JSON

Set-Content writes the JSON string to a file, creating or overwriting the output JSON file.

Alternative Approaches

Using Out-File instead of Set-Content

powershell

Import-Csv 'input.csv' | ConvertTo-Json | Out-File 'output.json' -Encoding utf8

Out-File allows specifying encoding explicitly, useful for UTF-8 output.

Using Get-Content with ConvertFrom-Csv

powershell

$csv = Get-Content 'input.csv' | ConvertFrom-Csv
$csv | ConvertTo-Json | Set-Content 'output.json'

Reads CSV as text then converts; useful if you want to manipulate CSV lines before conversion.

Using -Depth parameter with ConvertTo-Json

powershell

Import-Csv 'input.csv' | ConvertTo-Json -Depth 3 | Set-Content 'output.json'

Increase depth if CSV has nested objects or complex data structures.

Complexity: O(n) time, O(n) space

Time Complexity

The script reads each CSV row once and converts it to JSON, so time grows linearly with the number of rows.

Space Complexity

Memory usage grows linearly with the number of CSV rows because all data is loaded into memory before conversion.

Which Approach is Fastest?

Using Import-Csv piped directly to ConvertTo-Json is fastest and simplest; alternatives add overhead or complexity.

Approach	Time	Space	Best For
Import-Csv | ConvertTo-Json | Set-Content	O(n)	O(n)	Simple, direct CSV to JSON conversion
Get-Content + ConvertFrom-Csv + ConvertTo-Json	O(n)	O(n)	When preprocessing CSV lines is needed
ConvertTo-Json with -Depth parameter	O(n)	O(n)	Handling nested or complex CSV data