Molecular properties calculator

Calculate commonly used molecular descriptors from SMILES locally in your browser.

COSMolKit 0.2.12 / Rust / WASM

CANONICAL STRUCTURECC(=O)Oc1ccccc1C(=O)O

FormulaC9H8O4

Molecular weight180.159

g/mol

Exact mass180.04226

Heavy atoms13

atoms

H-bond donors1

HBD

H-bond acceptors3

HBA

Topological polar surface area63.60

A²

Rotatable bonds2

strict

Crippen logP1.310

logP

Formal charge0

BROWSER-LOCAL DESCRIPTORS

Calculate molecular properties from SMILES

COSMolKit parses the SMILES and calculates molecular formula, average molecular weight, monoisotopic exact mass, heavy atom count, hydrogen-bond donors and acceptors, TPSA, strict rotatable bonds, Crippen logP, and total formal charge without uploading the molecule.

PYTHON BACKEND

Calculate the same descriptors in Python

The Python package exposes the same COSMolKit descriptor implementations used by this browser tool.

COSMolKit Python 0.2.12

molecular_properties.py

from cosmolkit import (
    Molecule, calc_crippen_descriptors, calc_exact_mol_wt,
    calc_mol_formula, calc_mol_wt, calc_num_hba, calc_num_hbd,
    calc_num_rotatable_bonds, calc_tpsa,
)

mol = Molecule.from_smiles("CCO")
logp, _ = calc_crippen_descriptors(mol)

properties = {
    "formula": calc_mol_formula(mol),
    "molecular_weight": calc_mol_wt(mol),
    "exact_mass": calc_exact_mol_wt(mol),
    "heavy_atoms": sum(a.atomic_num() != 1 for a in mol.atoms()),
    "hbd": calc_num_hbd(mol),
    "hba": calc_num_hba(mol),
    "tpsa": calc_tpsa(mol),
    "rotatable_bonds": calc_num_rotatable_bonds(mol, mode="strict"),
    "logp": logp,
    "formal_charge": sum(a.formal_charge() for a in mol.atoms()),
}
print(properties)