NMR Chemical Shift Calculator

Calculator Inputs

Choose a mode, enter frequencies, then submit.

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Nucleus

Select the observed nucleus.

Reference

Common chemical shift reference standard.

Input mode

Choose Δν or absolute frequencies.

Spectrometer frequency (MHz)

Use the instrument frequency for the nucleus.

Peak offset Δν (Hz)

Keep your sign convention consistent.

Sample frequency νsample (Hz)

Absolute spectrometer readout for the peak.

Reference frequency νref (Hz)

Reference peak frequency in the same run.

Temperature (°C) (optional)

Useful for documenting shift variability.

Solvent (optional)

Record solvent for reproducibility.

Notes (optional)

Saved into downloads with your result.

Reset

Example data

Sample entries showing typical usage. Values are illustrative.

Nucleus	Mode	Spectrometer (MHz)	Δν (Hz)	δ (ppm)	Reference	Solvent
¹H	Δν	400	1200	3.000	TMS	CDCl₃
¹³C	Δν	100.6	7550	75.050	TMS	DMSO-d₆
¹⁹F	Absolute	376.5	-1882	-4.999	Other	CD₃CN

Formula used

Chemical shift is reported in parts per million (ppm) as a ratio between the peak frequency difference and the spectrometer frequency.

Δν = ν_sample − ν_ref (in Hz)
δ (ppm) = (Δν / ν₀) × 10⁶, where ν₀ is the instrument frequency in Hz
This tool accepts either Δν directly or absolute frequencies to compute Δν.

How to use this calculator

Select the observed nucleus and the reference standard.
Choose an input mode: enter Δν (Hz) or absolute frequencies (Hz).
Enter the spectrometer frequency in MHz for that nucleus.
Click Submit to show results above the form.
Use Download CSV or Download PDF to save your report.

FAQs

1) What is chemical shift in NMR?

Chemical shift is a normalized frequency difference between a peak and a reference, reported in ppm, allowing comparison across instruments.

2) Why do we use ppm instead of Hz?

Hz differences scale with spectrometer frequency. ppm removes that scaling, so the same compound shows comparable values on different instrument frequencies.

3) Which reference should I choose?

TMS is common for organic solvents. DSS is common for aqueous samples. Use the reference standard used in your experiment and keep it consistent.

4) Can δ be negative?

Yes. If your frequency difference is negative under your sign convention, the computed chemical shift will also be negative. Keep the same convention across reports.

5) What instrument frequency should I enter?

Enter the instrument frequency for the nucleus being observed, in MHz. A “400 MHz” proton instrument corresponds to a lower frequency for other nuclei.

6) How accurate is the result?

The math is exact for the inputs. Experimental accuracy depends on referencing quality, temperature, solvent effects, peak picking, and instrument calibration.

7) What do the downloads include?

CSV and PDF include nucleus, reference, mode, instrument frequency, Δν, δ, optional solvent, temperature, notes, and a timestamp for record keeping.

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