Kilohertz to terahertz: bridging radio and far infrared
What this conversion does
It divides by a billion, which spans the distance between the units used by radio engineers and those used by spectroscopists. A measurement made on a radio-frequency instrument and a line reported from a far-infrared spectrum can describe the same physical resonance, and this is the conversion that shows they do.
Two communities, one spectrum
Radio work is done in kilohertz and megahertz because the instruments are tuned with oscillators and the tuning steps are small. Far-infrared work is done in terahertz because the instruments are optical and the interesting features are broad. A rotational transition in a small molecule can be quoted either way, and being able to move between the two notations is what lets a result from one instrument be checked against the other.
Kilohertz to terahertz conversion table
Frequencies that straddle the boundary between electronic and optical measurement, listed in both units so the crossing point is visible.
| Kilohertz (kHz) | Terahertz (THz) |
|---|---|
| 1 | 1e-9 |
| 10 | 1e-8 |
| 100 | 1e-7 |
| 530 | 5.3e-7 |
| 1000 | 0.000001 |
| 1700 | 0.0000017 |
The awkward middle of the spectrum
There is a region where neither the electronic nor the optical toolkit is at its best, and it happens to be the region where many molecules have their rotational fingerprints. Instruments that work there have to borrow from both traditions, and their readouts sometimes come in kilohertz and sometimes in terahertz. Anyone reading across those two literatures needs the conversion almost daily.
Powers of ten, counted once
From kilohertz to terahertz is three steps of a thousand: to megahertz, to gigahertz, to terahertz. The exponent therefore moves by nine. Reading the exponent off the input and subtracting nine gives the answer without touching the digits.
Frequently asked questions
How do I convert kilohertz to terahertz?
Divide by a billion. A frequency of 500,000,000 kHz is 0.5 THz. The operation is three successive divisions by a thousand, so an input with fewer than ten digits will always give an answer below one terahertz.
Why would anyone need this conversion?
Because two fields measure the same phenomena in different units. A molecular rotation may be reported in the radio literature in kilohertz and in the optical literature in terahertz. Converting lets a reader check a value against a source written in the other tradition.
Does the converter lose precision on very small results?
No. Small values are written in exponent form so that significant digits are preserved rather than being swallowed by a run of leading zeroes. The number you get back is the exact quotient, not a rounded stand-in.
Is a terahertz the same as a thousand gigahertz?
Yes. One terahertz is a thousand gigahertz, and since a gigahertz is a million kilohertz, a terahertz is a billion kilohertz. Each SI prefix step is a factor of a thousand, with no exceptions in this chain.
What frequency range counts as terahertz?
Conventionally from about 0.1 THz to 10 THz, which in kilohertz is a hundred billion up to ten trillion. The boundaries are approximate — the term describes a region of the spectrum rather than a precisely defined band.