URL / Base64 / MD5 Converter — Encode & Decode Text Online
Free text encrypt/decrypt tool: URL encode & decode, Base64 and MD5 hash in one page. Instant results, supports Chinese and emoji, all in your browser.
About Text Encryption & Decoding
Free online text encrypt/decrypt tool with the three most-used text encoding algorithms on one page: URL encode, Base64 encode/decode and MD5 hash generator. Results appear as you type, Chinese and emoji are fully supported, and everything runs locally in your browser — no sign-up, no upload, works offline.
"Encrypt/decrypt" is the habitual name, but the three algorithms differ in nature: URL encoding and Base64 are reversible encodings (the original can be recovered), while MD5 is a one-way hash (only a fingerprint can be generated). The interface labels each direction clearly to prevent misuse. Switch algorithms with the segment control at the top, or press the ⇄ swap button between the panes to feed the result back and convert again — round-trip verification at a glance.
URL Encoding (Percent-Encoding)
URL encoding turns characters that are not allowed in URLs into %XX form: a space becomes %20, the Chinese character 你 becomes %E4%BD%A0, and & becomes %26. Two modes cover different scenarios:
- Component mode: for encoding a single parameter value —
& = ? +are all escaped so the parameter structure stays intact - Full URL mode: for encoding a complete address — structural separators like
& = ? /are preserved
For decoding, paste the %XX text and press Decode; invalid sequences such as %ZZ produce a clear error message instead of garbage. A quick-reference chart of common character encodings (space, &, #, Chinese, emoji) sits right below the converter.
Base64 Encode & Decode
Base64 represents arbitrary bytes with 64 safe characters (A-Z, a-z, 0-9, +, /): every 3 bytes of input become 4 characters, so length grows by about 33%. Base64 decode is one click as well — paste 5L2g5aW9 and immediately get 你好.
Two advanced options handle real-world scenarios:
- URL-safe alphabet: replaces
+/with-_and strips=padding, so the result can go straight into URLs, filenames and JWTs - Wrap at 76 chars: MIME email style, wrapping long output every 76 characters
Chinese text is processed as UTF-8, so encoding and decoding round-trip exactly with no mojibake.
Understanding MD5 the Right Way
MD5 encrypt is a high-volume search term, but MD5 is not encryption — it is a one-way hash function: any input length always yields a 32-character hexadecimal fingerprint, identical inputs yield identical results, a tiny change scrambles the output completely, and the original cannot be recovered from the fingerprint. Sites that claim to "decrypt MD5" merely look up precomputed rainbow tables, which fail on long texts and salted hashes.
Legitimate MD5 uses: verifying file integrity, generating cache keys, fingerprinting data for deduplication. When you need a stronger hash, choose SHA-256 or above. The tool switches to uppercase output in one click for platforms that require uppercase fingerprints.
Which Algorithm to Use
| Need | Use | Direction |
|---|---|---|
| Make Chinese/symbols safe in URLs and parameters | URL encoding | Reversible |
| Move any text through plain-text channels (email, JWT, data URI) | Base64 | Reversible |
| Fingerprint a file or string, verify integrity | MD5 | One-way |
Related tools
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- Word Counter — words, characters and platform limits at a glance.
- Case Converter — UPPER, lower, Title and programmer naming styles.
Chart tip: if the input contains invalid sequences like %ZZ, the tool shows a clear error instead of garbage output.
FAQ
Can MD5 be decrypted?
No. MD5 is a one-way hash function — the original text cannot be recovered from the 32-character digest. Sites that claim to "decrypt MD5" are just looking up precomputed rainbow tables of common passwords; they fail on long texts and salted hashes.
Is Base64 encryption? Is it secure?
No, Base64 is an encoding, not encryption. Anyone can decode it instantly, so never use it to protect passwords or secrets. Its value is letting data pass safely through plain-text-only channels (email, URLs, JSON).
Why does my Chinese Base64 decode to garbage?
Most likely the source data was encoded in a non-UTF-8 charset (such as GBK), or the last characters got lost when copying. This tool works in UTF-8, so Chinese text round-trips exactly.
Component mode or full URL mode — which should I use?
Use component mode to encode a single parameter value (& = ? are escaped, so the parameter structure stays intact); use full URL mode to encode a complete address (separators are preserved).
Is MD5 still safe for storing passwords?
Not recommended. MD5 is fast and covered by massive rainbow tables, so it is easy to crack by lookup. For password storage use a slow salted hash such as bcrypt, scrypt or Argon2; MD5 remains fine for file integrity checks and cache keys.
Does the tool upload my text?
No. All encoding, decoding and hashing happen in your browser — the tool works offline.