Enter your compound's Molecular Structure (SMILES) and Solvent, choose your NMR Type and Spectrometer Frequency, and the NMR Chemical Shift Calculator predicts your Chemical Shifts along with the Number of Signals, Chemical Shift Range, and a Prediction Confidence score — no spectrometer required.
Predicted Chemical Shifts
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Number of Signals
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Chemical Shift Range
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Prediction Confidence
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An NMR chemical shift predictor is a computational tool that uses machine learning or quantum mechanical calculations to predict the chemical shifts of atoms in organic molecules. It helps chemists estimate NMR spectra before running expensive experiments.
Modern prediction methods can achieve accuracy within 0.1-0.5 ppm for ¹H NMR and 1-3 ppm for ¹³C NMR. The accuracy depends on the molecular complexity, solvent, and the quality of the prediction algorithm used.
This calculator supports common deuterated NMR solvents including CDCl₃, D₂O, DMSO-d₆, and CD₃OD. Each solvent has different effects on chemical shifts due to hydrogen bonding and polarity differences.
SMILES (Simplified Molecular-Input Line-Entry System) is a text notation for describing molecular structures. For example, 'CCO' represents ethanol. You can draw structures in chemical drawing software and export as SMILES or find SMILES codes in chemical databases.
TMS (tetramethylsilane) is the standard reference for organic solvents, set to 0 ppm. DSS is used for aqueous solutions, and TSP is an alternative aqueous reference. The choice affects the absolute chemical shift values reported.
This calculator focuses primarily on chemical shift prediction. While it can estimate basic multiplicities based on molecular connectivity, detailed coupling constant prediction requires more specialized quantum mechanical calculations.
Small to medium-sized organic molecules with common atoms (C, H, N, O, S, P, F, Cl) work best. Very large molecules, metal complexes, or highly strained structures may have less accurate predictions due to computational limitations.
Chemical shifts in ppm are theoretically frequency-independent, but higher field strengths (higher MHz) can provide better resolution and more accurate experimental validation of predicted values. The calculator accounts for field-dependent effects where relevant.