1

Properties

RDKit · instant
Build a molecule to see its properties.
2

Quantum calculation

GFN2‑xTB / DFT
⚙️ Advanced — pick your own level of theory

Small molecules; higher levels run slower.

xTB = fast semi‑empirical · DFT/HF run real QM on our server. Reactivity indices appear after a DFT or orbital run.

3

Spectra & thermochemistry

IR · UV‑Vis · NMR · ΔG

Vibrational frequencies plus zero‑point energy, enthalpy, entropy and Gibbs free energy at 298 K (GFN2‑xTB Hessian).

UV‑Vis absorption

Excited states (TD‑B3LYP) → Gaussian‑broadened UV‑Vis absorption curve with the dominant orbital transition per band. Quick (3‑21G) for bigger molecules (≤~22 atoms); Advanced (6‑31G*) for near‑experimental λmax (small molecules, ≤~16 atoms).

NMR (¹H / ¹³C)

Predicted ¹H and ¹³C spectra with equivalent nuclei grouped and integrated. Quick is an instant empirical estimate (additivity, ChemDraw‑style); Advanced runs real GIAO B3LYP/6‑31G* quantum shieldings (≤22 atoms, up to a few minutes).

4

Orbitals, density & ESP maps

Psi4 · HF/3‑21G

Real molecular orbitals (Psi4) — click an energy level to view that MO (HOMO‑2 … LUMO+2), map the density/ESP, and adjust the isovalue. Blue/red lobes are the orbital phases. Small molecules only.

5

Conformers & dihedral scan

MMFF94

Automatic search

Generates conformers (ETKDG), ranks them by MMFF94 energy and Boltzmann‑weights the populations at 298 K.

Dihedral scan — set your own rotation

Pick a torsion and drive it through a range to map the rotational energy profile.

Build a molecule, then pick 4 atoms (i–j–k–l) in the 3D view; the j–k bond is rotated.

2D conformational map — a potential-energy surface

Scan two dihedrals at once for a Ramachandran-style energy map (e.g. pentane's two central C–C–C–C torsions).

6

Reactions & transition states

GFN2‑xTB path

Watch a bond-breaking, bond-forming reaction happen step by step. MoleBench drives the reactants together along a reaction coordinate (a relaxed GFN2‑xTB scan) — the energy maximum is the approximate transition state, and the path approximates the reaction (IRC).

Molecule library

presets

Export

save / share

A free account lets you save molecules and pick up where you left off. No account needed to use the tools.

Properties computed in your browser with RDKit. Drug‑likeness rules are guidelines, not verdicts.

Chemistry calculators

The everyday math — balance equations, reaction thermodynamics (ΔH, ΔS, ΔG, K), molar mass, mole conversions, dilutions, gas laws, pH.

Equation balancer

Type an equation with → or =, e.g. C3H8 + O2 -> CO2 + H2O.

Reaction thermodynamics — ΔH, ΔS, ΔG & K

Enter a balanced reaction using species from the table (include the phase, e.g. H2O(l)). Standard values are tabulated at 298.15 K; ΔG and K are recomputed at your temperature. Show available species ▾

Molar mass & mole converter

Handles parentheses and hydrates, e.g. Ca(OH)2, CuSO4·5H2O.

Dilution & gas law

C₁V₁ = C₂V₂ — leave one box blank, it's solved.

PV = nRT — leave one box blank. R = 0.0821.

pH & Beer–Lambert

pH of a strong acid/base from its concentration (mol/L).

Beer–Lambert A = ε·b·c — leave one box blank.

Simple pricing

Start free, no login. Server-side quantum calculations and the 29-lab curriculum come with a paid plan.

Free

$0 · no account

  • Build & view any molecule in 3D
  • Properties: MW, logP, TPSA, Lipinski
  • All molar-mass / dilution / gas-law / thermo calculators
  • 5 server calculations per day

Student

$10 / year

  • Everything in Free, plus:
  • Unlimited quantum calculations — DFT, NMR, orbitals, IR/UV-Vis, conformers, reactions & transition states, 1D/2D scans
  • All 29 guided labs (incl. structural biology)
  • Save molecules to your account

Pro

$120 / year

  • Everything in Student, plus:
  • Higher limits & priority compute for research-scale work
  • Best for power users running large or frequent jobs

Teaching a class? Email contact@ochemboard.com about classroom licenses.

Questions

Is it really free to start?
Yes. Building molecules, viewing them in 3D, reading their properties, and every calculator are free forever with no account — plus 5 server-side calculations a day to try the heavier tools.
What needs a paid plan?
The quantum calculations run on our compute servers — DFT, NMR, molecular orbitals, IR/UV-Vis, conformer searches, reaction & transition-state scans — and the 29-lab curriculum. Those are part of Student and Pro.
Can I cancel?
Anytime, from Manage in the header. Plans are annual and billed securely through Stripe — no hidden auto-upgrades.
Student vs Pro — which do I need?
Student ($10/yr) covers coursework and everyday study: unlimited standard calculations and all labs. Pro ($120/yr) raises the limits and adds priority for research-scale or high-volume use.

Real chemistry, computed in your browser.

GFN2‑xTB · Hartree‑Fock · DFT (B3LYP / PBE0 / M06‑2X) · molecular orbitals · ESP maps · IR spectra — in your browser, no install. Student access is $10/year.