In-browser RDKit.js · Dock tools
Lipinski Rule of 5 & Drug-likeness Checker
Paste SMILES to compute MW, LogP, HBD, and HBA — pass/fail Lipinski before you spend docking Credits.
Results appear here after you submit a valid SMILES string.
How to check Lipinski's Rule of 5 online
Christopher Lipinski's Rule of 5 (often written Rule of Five) is a quick oral drug-likeness filter used in medicinal chemistry and virtual screening. This free calculator runs RDKit.js (WebAssembly) in your browser — no desktop ChemDraw, SwissADME login, or local RDKit install required for the four classic descriptors.
- 1
Paste a SMILES string
Use Canonical or any valid SMILES from PubChem, ChemDraw, or our Name to SMILES converter. Rings, branches, and charges are supported when RDKit can parse the graph.
- 2
RDKit.js computes MW, LogP, HBD, HBA
Average molecular weight, Crippen LogP, Lipinski hydrogen-bond donors, and Lipinski acceptors are calculated locally via WASM — nothing is uploaded for this check.
- 3
Compare to classic Rule of 5 limits
Pass when MW ≤ 500, LogP ≤ 5, HBD ≤ 5, and HBA ≤ 10. Review each green check or red cross, then dock promising ligands with AutoDock Vina on Dock.
The four Lipinski Rule of 5 criteria
Each rule is a multiple of five — hence the name. Use them as a screening filter for oral small molecules, not as absolute ADMET truth.
Molecular weight ≤ 500 Da
Larger molecules often show poorer intestinal absorption. This checker uses RDKit average molecular weight (AMW) from the SMILES graph.
LogP ≤ 5
Octanol–water partition coefficient proxies lipophilicity. We report Crippen LogP from RDKit — a fast 2D estimate, not an experimental shake-flask value.
Hydrogen-bond donors ≤ 5
Classic Lipinski donors count OH and NH groups (lipinskiHBD). Too many donors can hinder membrane permeation.
Hydrogen-bond acceptors ≤ 10
Classic acceptors count N and O atoms (lipinskiHBA). This differs from some modern HBA definitions that exclude certain nitrogens.
Example molecules to test drug-likeness
Coursework and early virtual screens often start from familiar drugs. Click a name to run the live RDKit Rule of 5 check, then dock if the profile looks reasonable.
| Compound | Typical use | What to expect |
|---|---|---|
| NSAID teaching ligand | Typically passes all four | |
| Drug-like carboxylic acid | Classic oral Ro5 pass | |
| Small xanthine scaffold | Low MW / low LogP pass | |
| Polyphenol flavonoid | Often HBD / LogP edge cases | |
| Kinase inhibitor classic | Larger oral oncology ligand | |
| Statin / lipophilic acid | Useful for discussing violations |
Why check Rule of 5 before molecular docking?
AutoDock Vina and related docking tools will score almost any parsable ligand — even compounds that are unlikely oral drugs. Running a Lipinski Rule of 5 calculator first helps students and early discovery teams prioritize drug-like SMILES before spending queue time on huge polyphenols, peptides, or ultra-lipophilic hits.
This page targets the common search intent behind "rule of five calculator", "Lipinski drug-likeness checker", and "SMILES MW LogP HBD HBA online". Unlike spreadsheet hand-counts, RDKit.js applies consistent Crippen LogP and Lipinski donor/acceptor definitions so results match what many cheminformatics notebooks report.
After you pass (or knowingly accept a violation), convert a drug name with our chemical name to SMILES tool if needed, find a receptor with PDB search by protein name, clean waters with the PDB cleaner, set a box with the grid box calculator, then run docking on the Dock homepage. Docking reports also include RDKit Lipinski / Veber / QED summaries for each ligand.
Rule of 5 vs Veber, QED, and experimental ADMET
Lipinski filters are computational heuristics from Pfizer-era oral drug sets. Beyond Ro5, many teams also watch Veber rules (rotatable bonds and topological polar surface area) and QED (quantitative estimate of drug-likeness). Passing Rule of 5 does not prove oral bioavailability, solubility, or low toxicity — and failing it does not prove a compound is useless (many natural products and beyond-rule-of-5 oncology agents still matter).
Treat this checker as a triage step before docking and SAR discussion. For lab reports, state clearly that descriptors are RDKit-derived estimates, not SwissADME web results or measured assays.
Lipinski Rule of 5 FAQ
Short answers for students and researchers evaluating oral drug-likeness from SMILES before AutoDock Vina docking.
A rule-of-thumb filter for orally available small molecules: molecular weight ≤ 500, LogP ≤ 5, ≤ 5 hydrogen-bond donors, and ≤ 10 hydrogen-bond acceptors. It is a computational heuristic from medicinal chemistry, not a guarantee of bioavailability or safety.
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