This Base64 converter encodes text to Base64 and decodes Base64 back to text — with full UTF-8 support, running entirely in your browser.

Why Base64 Exists: Binary Data, Text-Only Roads

Email, URLs and JSON were built for text; Base64 repackages binary bytes as 64 safe characters (A–Z, a–z, 0–9, +, /) at a 33% size tax — 3 bytes become 4 characters. Its bit-level cousin is our Binary Converter. Part of our Other Calculators collection.

Worked Examples (Verified)

  • “Muse” → “TXVzZQ==” — the == is padding, completing the final 4-character group
  • “The Desmos Calculator” → “VGhlIERlc21vcyBDYWxjdWxhdG9y” — 21 bytes → 28 characters, exactly the 4/3 ratio
  • The alphabet ends with + and / in standard Base64; URL-safe variants swap those for − and _ and often drop padding (JWT tokens are the famous example)
  • Base64 is encoding, not encryption: anyone can decode it instantly (this page just did), so it protects against corruption and formatting — never against readers

Where You’ll Meet It

  • Email attachments (MIME), embedded images in HTML/CSS (data URIs), API tokens and basic-auth headers.
  • Padding (“=”) appears only at the end, 0–2 characters, aligning output to a multiple of 4.
  • Decoding failures almost always mean truncated copies or URL-safe variants fed to strict decoders (this one tolerates whitespace but requires correct padding).
  • Unicode: naive encoders break on characters beyond Latin-1 — this converter routes through UTF-8 bytes, so emoji and accented text survive the round trip.

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Frequently Asked Questions

How do I encode text to Base64?

Convert the text to bytes, regroup the bits from 8-bit bytes into 6-bit chunks, and map each chunk to the Base64 alphabet, padding the output to a multiple of four characters. “Muse” becomes “TXVzZQ==”. This converter does it instantly, with UTF-8 handling for non-English text.

Is Base64 encryption?

No — it’s a reversible encoding with no key. Anyone holding Base64 text can decode it with a tool like this one. Never store passwords or secrets as plain Base64 expecting protection; use hashing (for passwords) or real encryption (for data).

Why does Base64 end in = signs?

Padding: input bytes rarely divide evenly into 3-byte groups, so “=” characters fill the final group to four characters. One = means the last group held 2 bytes; == means 1 byte. URL-safe Base64 often omits padding since lengths can be inferred.

How much bigger does Base64 make data?

Exactly 4/3 the size (plus line breaks in email formatting): 3 bytes → 4 characters, a 33% overhead. That’s the price of squeezing arbitrary binary through text-only channels safely.

What is URL-safe Base64?

A variant replacing + with − and / with _ (characters that are safe inside URLs without escaping), usually without padding. You’ll see it in JWTs, web tokens and file-safe identifiers. Most decoders, this one included, handle the standard alphabet; swap −_ back to +/ if a strict source demands it.

Is this Base64 converter free?

Yes — free, instant, private (everything runs in your browser), no sign-up.