URL Percent Encoding Explained: Why Website Addresses Can Contain %20

The six points in the video

This is a silent video. The headings, explanations and labels below reproduce the information on screen.

1. 1

   Step 1: Recognise the percent pattern

   0:18

   A percent sign followed by two hexadecimal digits represents an encoded byte.

   On-screen labels: Percent sign; Two hexadecimal digits; Encoded byte.

2. 2

   Step 2: A space can become %20

   0:30

   Space handling depends on the URL or form-encoding context.

   On-screen labels: Space character; Percent-encoded space; Encoding context.

3. 3

   Step 3: Some symbols are separators

   0:42

   Characters such as question marks and ampersands can have structural roles.

   On-screen labels: URL structure; Reserved symbol; Component meaning.

4. 4

   Step 4: Encode values appropriately

   0:54

   A value containing a reserved symbol may need encoding within its component.

   On-screen labels: Individual value; Correct component; Preserved meaning.

5. 5

   Step 5: Avoid encoding it twice

   1:06

   An already encoded percent sign can be encoded again and change the result.

   On-screen labels: Original value; Existing encoding; Unexpected double encoding.

6. 6

   Step 6: Check the resulting link

   1:18

   Use suitable URL tools and verify the page receives the intended value.

   On-screen labels: Generated address; Expected value; Correct destination.

Common questions

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