Megahertz to Hertz Converter
Common Conversions
| MHz | Hz |
|---|---|
| 0.1 | 100000 |
| 0.5 | 500000 |
| 1 | 1000000 |
| 2 | 2000000 |
| 5 | 5000000 |
| 10 | 10000000 |
| 25 | 25000000 |
| 50 | 50000000 |
| 100 | 100000000 |
| 1000 | 1000000000 |
Why this conversion matters in chemistry
NMR spectrometers are identified by their proton Larmor frequency in MHz — a 400 MHz instrument operates at 9.4 T, a 600 MHz one at 14.1 T. Probe-tuning, network-analyzer measurements, and chemical-shift offsets read in raw Hz. A 600.13 MHz proton frequency is 600,130,000 Hz on a tuning sweep. Multiplying by 10⁶ is the clean prefix step. The same conversion is what underlies the chemical-shift formula δ (ppm) = Δν (Hz) / ν₀ (MHz) — divide the offset in Hz by the spectrometer frequency in MHz to get the field-independent ppm scale.
Formula
Where the factor comes from
Nothing in this pair was ever measured. Mega is 10⁶ by definition, the hertz is one cycle per second, and the second is fixed by a defined cesium transition frequency, so the conversion is a six-place shift of the decimal point and no more than that. What is worth extracting is how little energy a megahertz represents. Through E = hν, one MHz is 6.626 × 10⁻²⁸ J per photon, about 4 × 10⁻⁴ J/mol. At 400 MHz the photon energy is roughly 6 × 10⁻⁵ of kT at room temperature — which is exactly why nuclear spin populations differ by only tens of parts per million, and why NMR is such an insensitive technique despite the size of the magnet driving it.
Precision and significant figures
Multiplying by a million appends six zeros and none of them are significant figures. A nameplate 400 MHz becomes 400000000 Hz on paper, but only three digits were ever meaningful — the true carrier depends on the shimmed field and commonly sits a hundred kilohertz or more off the round number. Where the digits are real they run deep: a carrier logged as 600.1304 MHz is 600130400 Hz, seven meaningful figures whose last one lands at the 100 Hz level, and a console printing the carrier in hertz goes finer still, down toward the hertz a proton linewidth occupies. Scientific notation, 6.001304 × 10⁸ Hz, records the count honestly where a bare integer cannot. Take the figure count from what the instrument locked to, then move the decimal.
Worked Examples
A standard high-field NMR proton frequency, expressed in raw Hz.
The conversion anchor — one MHz equals exactly one million Hz.
A high-field NMR spectrometer frequency, used for routine biomolecular work.
Common mistakes
Coupling constants stay in hertz
A J value is field-independent: a 7.2 Hz doublet is 7.2 Hz on a 300 MHz instrument and on an 800 MHz one, while its separation expressed in ppm shrinks as the field rises. Nothing about a coupling should ever pass through the MHz label. Only the chemical-shift axis scales with the carrier, and conflating the two makes a perfectly good spectrum look mis-referenced.
Angular frequency carries a hidden 2π
Gyromagnetic ratios circulate in two forms — γ/2π at 42.577 MHz/T for protons, and γ itself at 2.675 × 10⁸ rad s⁻¹ T⁻¹. Relaxation theory and pulse-sequence algebra work in radians per second; the console and the nameplate work in hertz. Carrying a rad s⁻¹ value into a hertz calculation costs a factor of 6.28 that reads like an ordinary arithmetic slip rather than a unit error.
Nine-digit values get truncated on display
A frequency of 600130400 Hz dropped into a spreadsheet column formatted to three significant figures reads 6.00 × 10⁸, and the offset information that mattered is gone from the file rather than merely from the view. Instrument logs exported at default precision do the same. Keep frequencies in MHz, where the meaningful digits sit past the decimal point, and expand only at the last step.