One Number, Two Notations
The MHz-to-kHz conversion is the same operation as the kHz-to-MHz conversion, flipped: multiply by 1,000 instead of dividing. The reason both directions feel identical is that they are — the prefixes are exact powers of ten, and moving between them is always decimal-point arithmetic. What differs is the situation. A datasheet that specs a band-pass filter at "100.5 MHz" and a test setup that marks the same frequency "100,500 kHz" are describing an identical point on the spectrum. The engineer's job is to notice they're the same number.
The unit conventions aren't arbitrary — they follow the band plan. Below 30 MHz (HF and below), radio documentation often uses kHz; above 30 MHz (VHF and up), MHz is standard. A 28 MHz ham band is "28,000 kHz" in older books and "28 MHz" in modern ones. The FM band at 88-108 MHz is always MHz in consumer equipment, but the ITU's own frequency tables list it in Hz: 88,000,000 to 108,000,000. Every notation is correct; the conversions between them are exact.
kHz = MHz × 1,000
because 1 MHz = 10⁶ Hz and 1 kHz = 10³ Hz
The factor 1,000 is exact — a definition, not a measurement.
The Spectrum Analyzer's Two Notations
Spectrum analyzers are the place this conversion happens most. Set the center frequency to 100 MHz and the span to 20 MHz, and the marker readout may display in MHz while the resolution-bandwidth settings are in kHz. A 200 kHz resolution bandwidth — the analyzer's frequency resolution — is 0.2 MHz. The filter's 10 kHz span is 0.01 MHz. Keeping the two notations straight is a constant ×1,000/÷1,000 exercise, and it's exactly where a misread zero turns a measurement into noise.
Common Megahertz to Kilohertz Conversions
| MHz | kHz | Where you'd see this |
|---|---|---|
| 0.001 MHz | 1 kHz | The definitional anchor — one kilohertz. |
| 0.53 MHz | 530 kHz | Bottom of the AM broadcast band. |
| 1 MHz | 1,000 kHz | The boundary itself — 1,000 kHz. |
| 1.7 MHz | 1,700 kHz | Top of the AM broadcast band. |
| 3 MHz | 3,000 kHz | Bottom of the shortwave band. |
| 7 MHz | 7,000 kHz | The 40-meter ham band. |
| 12.1 MHz | 12,100 kHz | A typical shortwave station. |
| 30 MHz | 30,000 kHz | Top of HF, bottom of VHF. |
| 88 MHz | 88,000 kHz | Bottom of the FM band. |
| 100.5 MHz | 100,500 kHz | A typical FM station or RF test frequency. |
| 108 MHz | 108,000 kHz | Top of the FM band. |
| 300 MHz | 300,000 kHz | Bottom of the UHF region. |
Worked Examples
The filter datasheet vs the analyzer
A band-pass filter's datasheet says center frequency 100.5 MHz, 3-dB bandwidth 200 kHz. The spectrum analyzer's marker shows the filter at 100,500 kHz — the same center, converted. Checking the bandwidth: the analyzer's span control reads in kHz, so you set 200 kHz. The conversion between the datasheet's MHz and the instrument's kHz is exact: ×1,000. No approximation, no rounding — just three zeros.
The ham radio license exam
US ham radio exam questions love this conversion. "Which band is 7,000 kHz?" — answer: 7 MHz, the 40-meter band. "What is 146.52 MHz in kHz?" — 146,520 kHz. The exam tests fluency in both notations because the hobby spans them: HF in kHz/MHz, VHF/UHF in MHz. This converter is the study aid that makes the ×1,000 automatic.
Broadcast planning documents
An engineering consultant writes an FM station's channel authorization request. The FCC filing lists the channel in kHz ("100,500 kHz"), while the station's own technical documents say 100.5 MHz. The two must match exactly for the filing to be consistent. This page produces the conversion both directions, and because it's exact, the filing has no unit-induced discrepancy to explain.
Engineering Context
The ITU Radio Regulations define all frequency allocations in hertz, and national regulators (FCC, Ofcom) publish band plans in the prefixes that suit each range. The conversion between MHz and kHz is exact by the SI prefix definitions. For the next rung — MHz to GHz — see the MHz to GHz converter, and for the data rates carried by these channels (e.g., a 6 MHz TV channel at 19.4 Mbps) the data storage hub is the companion. The frequency hub collects all eight converters.
More: kHz to MHz · kHz to Hz · Hz to kHz · Frequency Guide
Related Unit Converters
Frequently Asked Questions
Is 100 MHz the same as 100,000 kHz?
Yes, exactly. 100 MHz × 1,000 = 100,000 kHz. Both describe a frequency of 100,000,000 Hz. The MHz form is compact for everyday use; the kHz form appears in engineering documents, spectrum displays, and regulatory filings that prefer three fewer digits of zeros. They are the same number, and the conversion is exact.
Why do some countries' radio docs use kHz where others use MHz?
Convention, not physics. Below 30 MHz, kHz has been traditional in European and international documentation; above 30 MHz, MHz is nearly universal. Some documents (especially ITU and older national tables) use Hz throughout. All conventions describe the same spectrum, and all conversions between them are exact powers of ten. The kHz to MHz page handles the opposite direction.
How do I convert MHz to Hz directly?
Multiply by 1,000,000. 2.4 GHz = 2,400,000,000 Hz = 2,400 MHz. The direct MHz-to-Hz factor is 10⁶; the MHz-to-kHz factor is 10³. Both are exact. For most engineering work, converting MHz to kHz (×1,000) then to Hz (×1,000 again) is the same as going straight — the chain is always exact.