Toolstead
Small, focused tools for everyday developer chores — no sign-up, no upload, no tracking. Open DevTools and watch the Network panel: converting anything produces zero requests.
Encoding
Base64 to Image
Paste any Base64 — prefixed, raw, wrapped, URL-safe or broken — and see the image.
Image to Base64
Get the exact string you need: Data URI, plain Base64, CSS, HTML or JSON.
Raw Base64 Decoder
No data: prefix required. The format is read from the bytes, not the label.
URL-safe Base64 to Image
Handles the - and _ alphabet used by JWTs, cookies and query parameters.
Base64 to PNG
Decode a raw string straight to a .png file, transparency preserved.
Base64 to JPG
Recognise a JPEG by its FF D8 FF signature, even without a prefix.
PNG to Base64
Encode a transparent PNG into a Data URI ready for CSS or JSON.
JPG to Base64 for CSS
Wrapped and quoted for a stylesheet or an email template.
Guides
Everything that tends to go wrong when you move an image through Base64 — and how to fix it.
Base64 Image Not Showing: How to Find the Real Cause
Six checks, cheapest first, that separate a bad string from a bad prefix from bytes that were never an image. Includes the two causes almost nobody checks.
Base64 Line Breaks and Padding: Why They Break Decoders
MIME wraps Base64 at 76 characters and padding rounds it to a multiple of four. What both rules are for, and how to handle strings that break them.
Base64 Overhead: Why Data URIs Make Files 33% Bigger
The 4-for-3 arithmetic behind Base64, why gzip cannot recover it for images, and where the break-even point for inlining an asset actually sits.
Base64 vs Hex, Base32 and ASCII85: Encodings Compared
Four ways to turn bytes into text, with different alphabets, different overhead and different failure modes. Which one belongs in which situation.
Why these tools are built this way
Your data never leaves the browser. Every tool here runs entirely client-side. There is no backend to send anything to — that is the reason the page keeps working when the network drops, and why a 5 MB image convert produces no requests at all.
Failures get explained, not just reported. The Base64 tools do not stop at "invalid input". They tell you the character that broke it, its exact position and code point, whether the length implies truncation, and whether those bytes are gzip rather than an image — then offer a one-click fix where one exists.
Offline by default. The site installs as a PWA, so once a tool has loaded it stays available with the network switched off — useful when you are debugging against an internal service.
No account, no history, no upload. If advertising is introduced later, it will be limited to clearly separated, fixed-height slots that never cover the working area.