Frequency Converters
Last updated: 2 June 2026
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Guide
Frequency: From Radio Stations to CPU Clock Speeds
Your car radio tunes to 96.7 FM. Your WiFi router broadcasts at 5GHz. Your laptop CPU runs at 3.2 GHz. These are all frequencies, measured in different ways, and they sound completely different because they're operating across vastly different scales. Understanding them explains why a 5GHz router is faster than 2.4GHz, and why a processor's clock speed isn't the whole story.
Frequency is how many times something happens per second. One hertz (Hz) is one cycle per second. Kilohertz (kHz) is 1,000 cycles per second. Megahertz (MHz) is 1,000,000 cycles per second. Gigahertz (GHz) is 1,000,000,000 cycles per second. Your CPU running at 3.2 GHz completes 3.2 billion cycles per second. That's fast, but even at that speed, some operations take multiple cycles.
Radio stations broadcast at frequencies measured in MHz. In Australia, FM radio uses 87.5-108 MHz. When the radio dial says "96.7", that's 96.7 million hertz. Each station gets a narrow frequency band. The ABC broadcasts across multiple frequencies, but the most famous is ABC Radio National at 105.3 MHz in Sydney (varies by city). AM radio uses lower frequencies, typically 540-1600 kHz. AM frequencies are 1,000 times lower than FM, which is why AM penetrates buildings better but has more static and is harder to modulate with clear audio.
WiFi operates in two main frequency bands: 2.4GHz and 5GHz. The 2.4GHz band is crowded (microwave ovens, cordless phones, and older devices all use it), so you get interference and slower speeds. The 5GHz band is less crowded and carries more data, but doesn't travel as far through walls. Newer routers support both bands simultaneously. The latest WiFi 6 and WiFi 6E routers add a 6GHz band, even less crowded. For most home use in Australia, 5GHz WiFi is fast and reliable if you're in the same room as the router.
Mobile phone frequencies are different again. Australia's 4G networks operate at various frequencies: 700MHz, 800MHz, 1.8GHz, 2.1GHz, and 2.6GHz depending on provider and location. 5G uses higher frequencies (around 3.5GHz in Australia). Higher frequency means more bandwidth and faster data, but shorter range. This is why 5G networks have smaller cell radius and need more base stations. Also, higher frequencies don't travel through walls as well, which is why early 5G didn't work indoors.
Audio frequency ranges from 20 Hz (lowest audible note for humans) to 20,000 Hz (20 kHz, the highest audible). A concert A note is 440 Hz. Bass frequencies are below 200 Hz. Treble is above 5 kHz. This is why a small speaker can't produce bass: it physically can't move slowly enough (at low frequencies). Subwoofers are specialised for frequencies below 200 Hz. When you see a speaker rated "20 Hz to 20 kHz", that means it attempts to reproduce the full range of human hearing.
RPM (revolutions per minute) is frequency for rotating objects. Your car engine at idle might be 700 RPM. At highway cruising, it might be 2,200 RPM. Maximum RPM (the red line) is usually 6,000-7,500 for a normal car. Diesel engines typically have lower maximum RPM (around 4,000-5,000) because they're built differently. A high RPM doesn't necessarily mean more power, because torque (rotational force) is different from frequency. A car might make its peak power at 5,500 RPM but peak torque at 4,000 RPM. This is why acceleration feels different at different engine speeds.
Common Questions
Why is 5GHz WiFi faster than 2.4GHz?
Higher frequency means more bandwidth, so more data can travel per second. The 5GHz band is also less crowded, so less interference from other devices. Downside: 5GHz doesn't penetrate walls as well. Range is shorter but speed is faster. Use 5GHz for devices in the same room. Use 2.4GHz if you need range and can tolerate slower speeds.
What's the difference between FM radio (96.7 MHz) and WiFi (2.4 GHz)?
FM radio uses megahertz (106 million Hz). WiFi uses gigahertz (2.4 billion Hz). WiFi operates at 1,000 times higher frequency than FM radio. Higher frequency lets you carry more data, but the signal travels shorter distances. Radio signals bounce off buildings. WiFi signals are absorbed or reflected by walls.
Can I hear a 15 kHz sound?
Maybe, if you're young and your hearing is good. Human hearing typically ranges 20 Hz to 20 kHz. Above 20 kHz is ultrasonic (dogs can hear this). Below 20 Hz is infrasonic. A speaker rated "20 Hz to 20 kHz" covers the full range. Most humans lose high-frequency hearing with age, so a 50-year-old might only hear up to 15 kHz.
Why does my car engine idle at 700 RPM?
At idle, the engine does just enough work to keep running against friction and parasitic losses. Too low and it stalls. Too high and it wastes fuel and heats up the engine. 700 RPM is a balance. Modern cars might idle lower because computers control the fuel injection precisely. Older cars needed higher idle speeds.
What does 3.2 GHz mean for a CPU?
It completes 3.2 billion clock cycles per second. Each cycle is a fraction of a nanosecond. Not all operations take one cycle. Some take many cycles. Also, modern CPUs have multiple cores running simultaneously, so a 4-core CPU at 3.2 GHz is potentially processing 12.8 billion instructions per second if all cores are fully utilised.
Why do FM radio stations get 1-2 MHz spacing but 5G networks use gigahertz?
FM radio carries audio only, which needs low bandwidth. Each station needs only about 0.2 MHz of bandwidth. 5G networks carry all types of data (video, gaming, calls). They need gigahertz of available spectrum to carry the volume. More bandwidth equals more data capacity. That's why 5G is faster: it uses higher frequencies with larger bandwidth per channel.
How We Verify Our Conversions
Every converter on RefDat uses peer-reviewed conversion factors sourced from the International Bureau of Weights and Measures (BIPM), the National Institute of Standards and Technology (NIST), and the Australian National Measurement Institute (NMI). Temperature formulas follow the ITS-90 international temperature scale. Cooking measurements use Standards Australia definitions (AS 1766) where applicable. We cross-check against multiple authoritative sources and test every calculator both forwards and backwards before publishing. If you spot an error, let us know.