TUTORIAL

How to Base64 Encode Text

Step-by-step guide to encoding plain text into Base64, covering padding rules and common use cases.

Problem

You need to convert a plain-text string into a Base64 representation so it can be safely transported over text-only channels such as JSON, XML, or HTTP headers.

Prerequisites

Basic understanding of ASCII and binary
Familiarity with a terminal or online encoder

Steps

1. Prepare the input text

Write down or paste the exact text you want to encode. Make sure there are no trailing newline characters unless you intentionally want them encoded. Even a hidden line break will change the output.
Input
```
Hello, World!
```
Output
```
SGVsbG8sIFdvcmxkIQ==
```
2. Encode the text to Base64

Feed the text into a Base64 encoder. The encoder splits the byte stream into 6-bit groups and maps each group to one of 64 printable characters. The output length is always a multiple of 4 characters.
Input
```
Hello, World!
```
Output
```
SGVsbG8sIFdvcmxkIQ==
```
3. Verify the padding

Check that the result ends with zero, one, or two '=' padding characters. Padding ensures the total length is a multiple of 4. If the output length is not divisible by 4, the encoding is invalid.
Input
```
SGVsbG8sIFdvcmxkIQ==
```
Output
```
valid (length 16, divisible by 4)
```

Expected result

A Base64 string that is a multiple of 4 characters in length, containing only A-Z, a-z, 0-9, +, /, and = padding.

Common errors

Output contains spaces or line breaks: Some encoders insert line breaks every 76 characters (MIME style). Use a raw Base64 encoder or strip whitespace before using the result.
Decoding produces extra characters: An invisible trailing newline was encoded. Trim the input before encoding if you do not want it.

Troubleshooting

If the output is not a multiple of 4, re-run the encoder with the same input and check for truncation.
Compare your result with an independent encoder to rule out character-set mismatches.