Frequency Converter

How to Use This Calculator

1. Enter the frequency value and select the From Unit.
2. Select the To Unit to see the conversion.
3. Use All Units tab to see the frequency in all 7 units at once.
4. Use Period tab to convert frequency to period (T = 1/f).
5. The Professional tab adds wavelength, angular frequency, and nearest musical note.

Formula

Example

Frequently Asked Questions

• How do I convert Hz to kHz? ▼
  To convert Hertz to kilohertz, divide by 1,000. To convert to megahertz, divide by 1,000,000. To convert to gigahertz, divide by 1,000,000,000. Examples: 440 Hz = 0.44 kHz; 1,000 Hz = 1 kHz; 100,000 Hz = 100 kHz; 1,000,000 Hz = 1 MHz; 2,400,000,000 Hz = 2.4 GHz. All frequency units use standard SI metric prefixes: kilo (k) = 10³, mega (M) = 10⁶, giga (G) = 10⁹, tera (T) = 10¹². Reverse conversions: 1 kHz = 1,000 Hz; 1 MHz = 1,000,000 Hz; 1 GHz = 1,000,000,000 Hz. The hertz (Hz) is named after Heinrich Hertz and means "cycles per second" — it replaced the older unit "cycles per second (cps)" in 1960.
• What is the relationship between frequency and period? ▼
  Frequency (f) and period (T) are exact reciprocals: T = 1/f and f = 1/T. Period is the time for one complete cycle, measured in seconds (or ms, μs, ns). Frequency is cycles per second (Hz). Examples: 440 Hz (concert A) → T = 1/440 = 0.002273 s = 2.273 ms; 50 Hz (AC mains, Europe) → T = 1/50 = 0.02 s = 20 ms; 1 MHz → T = 1 μs; 1 GHz → T = 1 ns; 60 Hz (AC mains, US) → T = 16.67 ms. Higher frequency means shorter period: audio (20 Hz–20 kHz) has periods of 0.05 ms to 50 ms; radio frequencies (kHz to GHz) have periods of microseconds to nanoseconds; visible light (400–700 THz) has periods of about 1.4–2.5 femtoseconds.
• How do I convert RPM to Hz? ▼
  To convert RPM (revolutions per minute) to Hz (revolutions per second), divide by 60. RPM / 60 = Hz. Examples: 60 RPM = 1 Hz; 600 RPM = 10 Hz; 3,000 RPM = 50 Hz; 3,600 RPM = 60 Hz; 10,000 RPM = 166.7 Hz. This is important for synchronous electric motor speeds: a 2-pole motor on 50 Hz mains runs at 3,000 RPM; a 4-pole motor runs at 1,500 RPM; a 6-pole motor at 1,000 RPM. On 60 Hz mains (US): 2-pole = 3,600 RPM; 4-pole = 1,800 RPM. To convert Hz to RPM, multiply by 60. Angular frequency (radians per second) ω = 2π × f = 2π × RPM/60. Example: 3,000 RPM = 50 Hz → ω = 2π × 50 = 314.16 rad/s.
• What is the wavelength of a 2.4 GHz WiFi signal? ▼
  The wavelength of a 2.4 GHz WiFi signal is approximately 12.5 cm (0.125 m). Wavelength λ = c/f, where c = speed of light = 299,792,458 m/s ≈ 3 × 10⁸ m/s, and f = 2.4 × 10⁹ Hz. Calculation: λ = 3×10⁸ / 2.4×10⁹ = 0.125 m = 12.5 cm. The 5 GHz WiFi band: λ = 3×10⁸ / 5×10⁹ = 0.06 m = 6 cm. Shorter wavelengths (5 GHz) pass through walls less effectively but carry more data. AM radio (1 MHz) has λ = 300 m; FM radio (100 MHz) has λ = 3 m; 4G LTE (700 MHz) has λ ≈ 43 cm; 5G millimeter wave (28 GHz) has λ ≈ 1.07 cm. The relationship λ × f = c is exact in vacuum; in other media, the speed of light is slower (c/n, where n is the refractive index), shortening the wavelength.
• What frequency is concert A? ▼
  Concert pitch A₄ (the A above middle C) is standardized at 440 Hz by the International Organization for Standardization (ISO 16). One octave higher is A₅ = 880 Hz; one octave lower is A₃ = 220 Hz; A₂ = 110 Hz; A₁ = 55 Hz. Each octave doubles (or halves) the frequency. Middle C is C₄ ≈ 261.63 Hz. The full piano keyboard spans about 27.5 Hz (A₀, lowest) to 4,186 Hz (C₈, highest). Human hearing range: approximately 20 Hz to 20,000 Hz (20 kHz), degrading with age. The 440 Hz standard was established internationally in 1939 and confirmed in 1955/1975 by ISO. Some orchestras (particularly in Europe) tune to A = 442 or 443 Hz for a brighter sound, creating a slight deviation from the international standard.

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