a chemistry scratchpad
Paste a SMILES. See the molecule.
A SMILES string is easy to write and impossible to picture. Molsnap turns it into a real 2D structure, a spinnable 3D model, and the molecular formula and weight, instantly, in your browser. No account, no upload, no install.
Open Molsnap →Free. Runs entirely client-side.
Real 2D layout
Bond geometry and ring layout computed from the SMILES itself, not a lookup image. Any valid structure renders, not just a curated few.
A spinnable 3D model
Atoms relax into three dimensions right in the page and orbit under your cursor. Grab it, zoom it, pause it.
Formula and weight, always in sync
Hill-notation formula and molecular weight computed from the same atom accounting as the structure, never a mismatched placeholder.
Reading a SMILES string without the desktop software
SMILES (Simplified Molecular Input Line Entry System) is the
shorthand chemists use to write a molecule as plain text.
O is water, CCO is ethanol, and
CC(=O)Oc1ccccc1C(=O)O is aspirin. It fits in a
spreadsheet cell, a URL, or one line of a paper, which is exactly why
it turns up everywhere and exactly why it is so hard to read at a
glance. The parentheses, ring-closure digits, and lowercase aromatic
atoms carry real structure your eye cannot reconstruct on its own.
Molsnap closes that gap. Paste a SMILES string, press render, and it draws the flat 2D skeleton, builds a 3D model you can spin and zoom, and prints the Hill-notation formula and molecular weight, all computed in your browser. Nothing is uploaded, so a structure you are still keeping to yourself stays on your machine, and the page keeps working once it has loaded even if you lose your connection.
How to use it
- Paste a SMILES string into the input at the top of the app, or tap an example chip (aspirin, caffeine, ibuprofen, benzene, water).
- Press render. The 2D and 3D panels fill in and the formula and weight appear.
- Drag the 3D model to orbit it, scroll to zoom, and use the pause button to stop the auto-rotate.
- Copy the link from your address bar. The SMILES is stored in the URL, so the exact render reopens for anyone you send it to.
Common questions
- Is Molsnap free?
- Yes. It is free, needs no account, and runs entirely in your browser.
- Does my SMILES get sent to a server?
- No. Parsing, the structure layout, the 3D coordinates, and the formula and weight are all computed client-side. Your input never leaves the page.
- How accurate is the 3D model?
- It is a fast approximation, not a validated conformer. Molsnap relaxes the 2D layout into 3D with a distance-geometry method so shapes look plausible and spin well. Reach for dedicated software when you need energy-minimized geometry.
- Which molecules does it handle?
- Everyday organic chemistry: chains, branches, rings, aromatics, double and triple bonds, charges, and the common heteroatoms and halogens. A SMILES it cannot parse shows a clear error instead of a wrong picture.
- What is the molecular weight based on?
- Standard atomic weights summed over every atom, including the hydrogens added explicitly during parsing, so the formula and the weight always agree.