Tiny Online Tools
WASM Size Analyzer answers a question every large .wasm module raises sooner or later: what's actually taking up all this space? It parses the module's own section and function encoding — not an estimate, the exact byte length of every function body and data segment — and shows you where the bytes went, entirely in your browser.
What you get
- Treemap — the largest functions in the module, laid out as proportionally-sized rectangles so the biggest contributors are visually obvious at a glance. Click a box for its exact size and signature.
- Functions — every function sorted by size, with its byte count and share of the total file, exportable as CSV for further digging.
- Data segments — the same breakdown for a module's data segments (string literals, static tables, embedded assets).
- Sections — a section-level summary reconciling code, data, custom sections, and structural overhead back to the exact total file size.
Why this matters
When a .wasm bundle is bigger than expected, "which function is 40% of my binary" is a much more actionable question than staring at a total byte count. This tool turns that question into a sorted list and a picture, so you can decide what's actually worth optimizing, splitting out, or compiling with different flags — instead of guessing.
Good to know
Every size shown here is exact, read directly from the binary's own length-prefixed section and function encoding — never an estimate. The treemap itself is a simple proportional layout (not a squarified algorithm) chosen for legibility over visual polish; box position doesn't correspond to where bytes physically sit in the file, only relative size does. For a byte-offset map of the file instead, see the WASM Binary Explorer tool.