Druglikeness Calculator

In short: Druglikeness calculator for SMILES or compound names. It is free, works in your web browser and needs no download.

Enter a SMILES string or compound name to calculate a simple druglikeness guideline score from Lipinski and Veber-style properties.

How the Druglikeness Score Works

This tool combines six common medicinal chemistry property checks: Lipinski molecular weight, LogP, H-bond donors, H-bond acceptors, plus Veber-style TPSA and rotatable bond checks. The score is the percentage of these checks that pass.

• Use it for quick triage, teaching, and early compound comparison.
• Do not treat the score as a prediction of potency, safety, or approval likelihood.
• Natural products, macrocycles, prodrugs, and specialized target classes may fall outside these simple guidelines.

Reading the result

Druglikeness rules are quick filters that flag molecules less likely to be orally absorbed. Lipinski's rule of five, published by Lipinski and colleagues in 1997, suggests poor absorption is more likely when a compound has more than 5 H-bond donors, more than 10 H-bond acceptors, a molecular weight over 500, or a calculated logP over 5. Veber's criteria add rotatable bonds (10 or fewer) and polar surface area (140 Ų or less).

What the rules do not tell you

• They are guidelines, not predictions of activity, toxicity, or metabolism.
• Many approved drugs break one or more rules, notably natural products, antibiotics, and drugs absorbed by transporters.
• They apply to oral delivery; injectables and topical products follow different constraints.

Example: ibuprofen (C₁₃H₁₈O₂, about 206 g/mol, one donor and two acceptors) passes the Lipinski checks comfortably. Use the score to prioritise or compare a series of analogues, then look at individual properties with the LogP and TPSA calculators.