Cycles per Second (cps) - Unit Information & Conversion

Quick Answer

What is Cycles per Second? Cycles per second (cps) is the old name for hertz (Hz). 1 cps = 1 Hz = 1 complete oscillation per second. The term "hertz" replaced "cycles per second" in 1960 to honor physicist Heinrich Hertz. You may see "cps" in older technical documents, but Hz is now standard. 1 cps = 1 Hz exactly. Use our frequency converter for instant conversions.

Key Facts: Cycles per Second

Property	Value
Symbol	cps
Quantity	Frequency
System	Metric/SI Derived
Derived from	Hertz
Category	Frequency
Standard Body	NIST / ISO

Definition

1 cps = 1 Hz = 1 cycle per second = 1 complete oscillation per second

History

Before 1960: "Cycles per second" was the standard term

• Common abbreviations: c/s, c.p.s., cps, ~/s

1960: Renamed to "hertz" (Hz)

• Honors Heinrich Hertz (1857-1894)
• Adopted at 11th CGPM (General Conference on Weights and Measures)
• Simplified terminology and standardized notation

Why the change?

• Shorter, more convenient
• Honors a pioneering physicist
• Consistent with other SI units named after scientists (ampere, watt, volt, etc.)
• International standardization

Common Uses (Historical & Current)

Historical Technical Documents: Pre-1960 radio, electronics, and acoustics literature - understanding older specs. Some Fields Still Use "cycles": Audio engineering may say "cycles" colloquially. Education: Teaching frequency concepts before introducing Hz notation. Older Equipment: Vintage test equipment labeled in cps. Legacy Systems: Industrial control systems that predate 1960 standardization.

Real-World Historical Conversions

Old Radio Frequency Standards (cps/kc/s notation)

How vintage equipment was labeled:

Service	Old Notation	Modern (Hz)	Equipment Era
AC Power	60 cps	60 Hz	Pre-1960 all regions
AM Radio	550-1600 kc/s	550-1600 kHz	1920s-present
Shortwave	3-30 Mc/s	3-30 MHz	1920s-present
FM Radio	88-108 Mc/s	88-108 MHz	1930s-present
VHF TV	54-216 Mc/s	54-216 MHz	1940s-present
UHF TV	470-890 Mc/s	470-890 MHz	1950s-present
CB Radio	26.5-27.4 Mc/s	26.5-27.4 MHz	1960s-present

Key insight: Old radio frequencies still use the same band ranges; only the notation changed

Equipment Labeling Over Time

How the same frequency was labeled on test equipment:

Equipment Type	Pre-1960 Label	Post-1960 Label	Actual Frequency
Oscilloscope	"Freq: 1000 cps"	"Freq: 1 kHz"	1,000 Hz
Signal generator	"Output: 100 kc/s"	"Output: 100 kHz"	100,000 Hz
Frequency meter	"0-10 Mc/s range"	"0-10 MHz range"	0-10,000,000 Hz
Audio analyser	"10 cps - 100 kc/s"	"10 Hz - 100 kHz"	10 Hz to 100,000 Hz

Reading old manuals: Simply replace "cps" with "Hz", "kc/s" with "kHz", "Mc/s" with "MHz"

Audio Engineering Historical Terminology

How audio specs evolved:

Spec	Old Notation	Modern Notation	Context
Human hearing	20-20,000 cps	20-20,000 Hz	Audible frequency range
Telephone	300-3,400 cps	300-3,400 Hz	Bandwidth limit
AM radio	Modulation up to 5 kc/s	Modulation up to 5 kHz	Bandwidth
FM radio	Modulation up to 15 kc/s	Modulation up to 15 kHz	Bandwidth
High-fidelity audio	20-20 kc/s flat response	20-20 kHz flat response	Frequency response spec

Colloquial: Audio engineers might still say "20-20 cycles" informally, but professionally use "Hz"

Prefix Equivalence Over Time

How metric prefixes worked with cycles/second:

Modern (Hz)	Old Notation	Value
Hz	cps or c/s	1
kHz	kc/s or kc	1,000
MHz	Mc/s or Mc	1,000,000
GHz	Gc/s (rarely used)	1,000,000,000
THz	Tc/s (extremely rare)	1,000,000,000,000

Complexity: Using Mc/s and kc/s together was awkward (mixing metric with old terminology)

Is cps the same as Hz?

Yes, exactly the same:

• 1 cps = 1 Hz
• 1 kilocycles per second (kcps or kc/s) = 1 kHz
• 1 megacycles per second (Mcps or Mc/s) = 1 MHz

Only difference: Terminology and era

• cps: Used before 1960
• Hz: Used from 1960 onwards (current standard)

Example conversions:

• 60 cps = 60 Hz (AC power)
• 1000 cps = 1 kHz (audio frequency)
• 100,000 cps = 100 kHz (AM radio range)

cps to Hz converter →

Why was cps changed to hertz?

Reasons for the 1960 change:

1. Brevity: "Hz" is shorter than "cycles per second"
2. Honor: Named after Heinrich Hertz who proved electromagnetic wave existence
3. Standardization: Consistent with ampere, watt, volt, newton, pascal
4. International: Single symbol understood globally
5. Simplicity: Easier for metric prefixes (kHz, MHz, GHz vs kcps, Mcps, Gcps)

The change was purely nomenclature - the measurement itself remained identical.

When do I still see "cycles per second"?

Where you might encounter cps:

Historical documents:

• Pre-1960 radio manuals
• Vintage audio equipment
• Old electrical engineering textbooks

Colloquial use:

• Audio engineers may say "cycles" informally
• Explaining frequency concepts to beginners
• When emphasizing the cyclic nature

Vintage equipment:

• Old oscilloscopes
• Antique signal generators
• Historical test equipment

Recommendation: Use Hz in all modern contexts. Only use cps when discussing historical equipment or documents.

How do I convert kc/s (kilocycles per second) to Hz?

Formula: Hz = kc/s × 1,000

Examples:

• 1 kc/s = 1,000 Hz = 1 kHz
• 10 kc/s = 10,000 Hz = 10 kHz
• 1000 kc/s = 1,000,000 Hz = 1 MHz

Old radio terminology:

• AM radio: 550-1600 kc/s = 550-1600 kHz
• Shortwave: 3-30 Mc/s = 3-30 MHz

kHz to Hz converter →

What is Mc/s (megacycles per second)?

Mc/s = Megacycles per second (historical term)

Modern equivalent: MHz (megahertz)

Conversion: 1 Mc/s = 1 MHz = 1,000,000 Hz

Historical usage:

• FM radio: 88-108 Mc/s → now 88-108 MHz
• VHF TV: 54-216 Mc/s → now 54-216 MHz
• Old radio communications

Old abbreviations:

• Mc/s, Mc, Mcps all meant megacycles per second
• Now standardized as MHz

MHz to Hz converter →