How do I decode a Base62 string?

To decode a Base62 string, paste it into the input field and the tool will automatically convert it back to the original text. Base62 decoding is case-sensitive, so make sure to preserve the exact capitalization from the original encoded string. The decoder accepts the 62-character alphabet: 0-9, A-Z, and a-z. Any invalid characters will trigger an error message. The decoding happens instantly in your browser without any server uploads, ensuring complete privacy. Base62 uses only alphanumeric characters (no special symbols like Base64's plus and slash), making it URL-safe and ideal for short URLs and compact identifiers. You can copy the decoded result to clipboard or download it as a text file.

Why does case matter when decoding Base62?

Base62 is case-sensitive, meaning it treats uppercase and lowercase letters as completely different characters. For example, 'A' (uppercase) represents a different value than 'a' (lowercase). If you change the case of even one character in a Base62 string, the decoding will produce completely different output or fail entirely. Always copy and paste Base62 strings to preserve exact capitalization. This case sensitivity is what gives Base62 its 62 unique characters: 10 digits (0-9), 26 uppercase letters (A-Z), and 26 lowercase letters (a-z). URL shorteners and ID generators rely on this case distinction to create more compact identifiers—removing case sensitivity would reduce the alphabet to just 36 characters and require longer strings. When working with Base62 data, never normalize case or convert to all uppercase/lowercase.

What characters are invalid in Base62?

Base62 only accepts alphanumeric characters: digits 0-9, uppercase letters A-Z, and lowercase letters a-z. Any other characters including spaces, punctuation, special symbols, or Unicode characters are invalid and will cause decoding errors. If you encounter an error, check for accidentally copied spaces, line breaks, or special characters. The decoder typically ignores whitespace (spaces, tabs, newlines) by stripping it before processing, but other invalid characters will cause failures. Common mistakes include including URL prefixes (http://), domain names (bit.ly/), hyphens, underscores, or the equals signs used in Base64 padding. Base62 has no padding characters, so any string length is valid as long as all characters come from the 62-character alphabet.

Can I decode short URLs with this tool?

You can decode the Base62 identifier portion of short URLs, but not the full URL. For example, if you have a short URL like bit.ly/Abc123, you would decode only the 'Abc123' part. However, URL shorteners typically encode numeric database IDs, not readable text, so decoding will give you a number or binary data rather than meaningful text. The main use case is understanding how URL shorteners generate compact identifiers. Most URL shorteners store a numeric ID in their database and encode it to Base62 to create short, URL-safe strings. When you decode these, you get back the original numeric ID. Some systems encode random bytes for uniqueness, which will appear as garbled characters when decoded to text. Use the Base62 to File tool if you need to decode Base62-encoded file data or binary content.

Can I decode YouTube video IDs?

YouTube video IDs use a Base64-like encoding (not Base62), so this tool won't correctly decode them. YouTube IDs use 64 characters including hyphens and underscores, while Base62 uses only 62 alphanumeric characters. If you try to decode a YouTube ID containing hyphens or underscores, you'll get an invalid character error. Use a Base64 decoder for YouTube IDs instead. However, some other platforms like Imgur, Flickr, and various URL shorteners do use Base62 for their identifiers and will decode correctly with this tool. The key difference: Base62 contains only 0-9, A-Z, and a-z (62 total), while Base64 also includes plus, slash, and equals for padding (64 total). When you encounter an identifier with special characters, it's likely Base64 or a custom encoding scheme.

Why is my decoded output empty or garbled?

Empty or garbled output usually means the Base62 string was not originally encoded from text. If the original data was a file, binary data, or a numeric ID, decoding will produce non-printable characters or appear empty. Base62 is often used to encode numbers or binary data for compact identifiers, not human-readable text. To decode Base62-encoded files, use the Base62 to File tool instead. For example, URL shorteners encode database IDs (numbers), so decoding produces numeric bytes that display as strange characters. Image hosting services might encode file hashes or binary data. If you see control characters, null bytes, or random symbols, the original data was binary. If the output is completely empty, the encoded string might represent a zero value or empty data. Try encoding and decoding a test string to verify the tool works correctly with text data.

Does whitespace affect Base62 decoding?

Whitespace (spaces, tabs, line breaks) is typically ignored during Base62 decoding and stripped automatically. You can paste Base62 strings with formatting or line breaks, and the decoder will remove them before processing. However, be careful with spaces that might be part of encoded data versus formatting spaces. When in doubt, copy the exact Base62 string without any added formatting. Some systems split long Base62 strings into chunks for readability (like 'AbC DeF GhI'), and these spaces should be removed before decoding. The tool handles this automatically. However, if you're working with a system that uses spaces as delimiters between multiple Base62 values, you'll need to decode each chunk separately. Always check your source system's documentation to understand how whitespace is handled in their Base62 implementation.

How can I verify a Base62 string is valid?

A valid Base62 string contains only characters from the 62-character alphabet: 0-9, A-Z, and a-z. The decoder will validate this automatically and show an error for invalid characters. Additionally, the string length doesn't have special requirements (unlike Base64 padding), so any length is acceptable as long as all characters are valid. If decoding succeeds without errors, your Base62 string is structurally valid. However, structural validity doesn't guarantee the decoded content is meaningful—a valid Base62 string might decode to gibberish if it was corrupted, truncated, or represents binary data rather than text. To fully verify, you can re-encode the decoded output and compare it to the original Base62 string. If they match, the decoding was successful and the data round-trips correctly. For production systems, implement checksum validation or use Base62 with error detection codes.

Can I detect if a string is Base62-encoded?

There's no definitive way to detect Base62 encoding since Base62 strings look like any alphanumeric text. A string containing only 0-9, A-Z, and a-z might be Base62-encoded or just regular alphanumeric text. Context clues help: if the string comes from a URL shortener, database ID, or tracking system, it's likely Base62. If decoding produces readable text, it was probably encoded; if it produces garbage or binary data, it might not be Base62 or was encoded from non-text data. Some hints that suggest Base62 encoding include: uniform character distribution across digits and letters; no natural language word patterns; consistent length matching your system's ID format; strings appearing in URLs or APIs where compact identifiers are needed; and lack of vowel-heavy patterns (natural text tends to have vowel patterns). When in doubt, try decoding—if the output makes sense, it was likely encoded.

Is there a limit to Base62 string length?

This tool can decode Base62 strings of any reasonable length, though extremely long strings (megabytes) may take longer to process. Base62 is typically used for compact identifiers (short URLs, IDs), so most strings are relatively short. For decoding Base62-encoded files, use the Base62 to File tool which is optimized for large data. Browser memory limits may apply for extremely long strings, but you're unlikely to encounter these in normal usage. As a general rule, strings under 1MB decode instantly, strings 1-10MB may take a few seconds, and strings over 10MB should use the file-specific tool. The mathematical properties of Base62 mean that a 10-character Base62 string can represent about 839 quintillion unique values, so very few real-world use cases need strings longer than 10-20 characters. Database IDs, session tokens, and short URLs typically use 6-12 character Base62 strings.

Free Base62 Decoder Online

Decode Base62 strings back to readable text instantly. Convert Base62 encoded data (short URLs, compact IDs) to original text format. 100% free, secure, case-sensitive, and works in your browser.

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