Convert String to Base64 and Base64 to String

System.Text.Encoding class provides methods to convert String to Base64 and vice-versa.

Convert String to Base64

First convert the string to a byte array and then use the Convert.ToBase64String() method to convert the byte array to a Base64 string.


    byte[] byt = System.Text.Encoding.UTF8.GetBytes(strOriginal);

    // convert the byte array to a Base64 string

    strModified = Convert.ToBase64String(byt);


    Dim byt As Byte() = System.Text.Encoding.UTF8.GetBytes(strOriginal)

    ' convert the byte array to a Base64 string

    strModified = Convert.ToBase64String(byt)

Convert Base64 string to String

In order to convert a Base64 string back to the original string, use FromBase64String(). First FromBase64String() converts the string to a byte array and then use the relevant Encoding method to convert the byte array to a string, in our case UTF8.GetString();


    byte[] b = Convert.FromBase64String(strModified);

    strOriginal = System.Text.Encoding.UTF8.GetString(b);


    Dim b As Byte() = Convert.FromBase64String(strModified)

    strOriginal = System.Text.Encoding.UTF8.GetString(b)

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About The Author

Suprotim Agarwal
Suprotim Agarwal, ASP.NET Architecture MVP (Microsoft Most Valuable Professional) works as an Architect Consultant and provides consultancy on how to design and develop Web applications.

Suprotim is also the founder and primary contributor to DevCurry, DotNetCurry and SQLServerCurry. He is the Editor of a Developer Magazine called DNC Magazine. He has also written two EBooks 51 Recipes using jQuery with ASP.NET Controls. and The Absolutely Awesome jQuery CookBook

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11 Responses to "Convert String to Base64 and Base64 to String"
  1. Anonymous said...
    September 1, 2009 at 12:29 AM

    Thanks for this code.
    it is really useful for me

  2. Anonymous said...
    June 28, 2010 at 7:10 AM

    That was help full


  3. Illutionist said...
    July 9, 2010 at 3:01 AM

    Thats it ! simple


  4. Anonymous said...
    November 4, 2010 at 12:37 PM

    This was really lucid and it worked. Thnaks.

  5. Anonymous said...
    December 7, 2011 at 11:29 PM

    wow Excellent..........

  6. Anonymous said...
    April 12, 2012 at 1:34 AM

    Thank you so much for this! :)

  7. Nipesh Shah said...
    May 1, 2012 at 6:10 AM

    Time Saving Code


  8. Anonymous said...
    May 1, 2012 at 1:45 PM

    thank you!!!

  9. Anonymous said...
    October 3, 2013 at 4:25 AM


  10. Anonymous said...
    October 11, 2013 at 2:07 AM

    Thanks very much for this sample

  11. buyi wen said...
    September 21, 2015 at 11:30 PM

    I'm not a developer, i always use the free online base64 string converter to encode and decode base64.


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