What does "accurate" actually mean for a frequency converter?

Accuracy means every conversion uses exact constants and full precision. SI prefixes are exact powers of ten, rad/s uses 2π exactly, and per-minute units divide by the integer 60. A round trip — converting the answer back to the starting unit — should always return your original number with no drift.

How do you round-trip check a frequency conversion?

Convert the result back to the unit you started with. If the value matches your original input, the conversion is accurate. For Hz to MHz to Hz, 0.5 MHz should come back as 500,000 Hz. For rad/s, the round trip only closes exactly when the converter uses 2π, not an approximation like 6.2832.

Are mHz and MHz conversions exact?

Yes. Millihertz is 10⁻³ Hz and megahertz is 10⁶ Hz, both exact powers of ten per BIPM definitions. A value written in mHz converts to Hz, kHz, MHz, GHz, or THz with no loss of digits, because the only operation is shifting the decimal point by whole thousands.

Why is a rad/s number about 6.28 times larger than the same Hz value?

Because one full cycle sweeps 2π radians, angular frequency equals 2π·f. So 1 Hz equals 2π rad/s, which is about 6.283185 rad/s. The rad/s number looks bigger but represents the same rotation in different units. Note that this means a rad/s figure describes a slower cycle than the same number in Hz, since rad/s is the larger unit.

Can a frequency converter be exact and still private?

Yes. The Frequency Converter runs all conversions in your browser using exact SI and trigonometric constants, so the math stays precise. Nothing is uploaded, which means the values you enter — for example, a proprietary motor speed or a personal heart rate — never leave your device.

Accurate Frequency Converter: Hz, kHz, MHz, GHz & More

An accurate frequency converter changes the unit that measures how often a repeating event occurs — hertz (Hz), kilohertz (kHz), megahertz (MHz), gigahertz (GHz), terahertz (THz), millihertz (mHz), revolutions per minute (rpm), beats per minute (BPM), radians per second (rad/s), and degrees per second (deg/s) — by routing every conversion through hertz, the SI base unit for one cycle per second. Because the SI prefixes are exact powers of ten following BIPM definitions (kilo is 10³, mega is 10⁶, giga is 10⁹, tera is 10¹², milli is 10⁻³), scaling between Hz and any of these prefixes is mathematically exact with no rounding error. Angular and per-minute units are likewise handled with closed-form constants: omega = 2π·f for rad/s, 360 degrees per cycle for deg/s, and 60 seconds per minute for rpm and BPM. A converter built on these definitions returns your original value when you convert the answer back to the starting unit, which is the practical test of accuracy. The Frequency Converter applies these constants precisely in your browser, so any pair of supported units stays consistent and round-trip safe.

What makes a frequency converter accurate

Three ingredients decide whether a frequency converter is accurate: the base unit it routes through, the constants it uses for non-SI units, and the precision it preserves between conversions. Routing through hertz means every pair of supported units shares one common reference, so a value written as 2.4 MHz becomes 2,400,000 Hz and 0.0024 GHz with no drift. The second ingredient is the constants for non-SI units — 2π for rad/s, 360 for deg/s, and 60 for rpm and BPM. The third ingredient is precision, because a tool that truncates digits or uses rounded constants like 6.2832 instead of 2π will fail a strict round-trip check. When all three are in place, the same input always produces the same output, and reversing the conversion reproduces the original number to full precision.

The SI prefix ladder: exact factors from mHz to THz

The ladder of SI prefixes is the backbone of frequency conversion between Hz, kHz, MHz, GHz, and THz. Each step up the ladder is exactly a factor of 1000, so converting Hz to kHz, kHz to MHz, or MHz to GHz is mathematically the same operation: shift the decimal point three places. Going downward, millihertz sits three places below hertz, useful for very slow oscillations such as tides or geological cycles.

Unit	Symbol	Exact factor vs 1 Hz
Terahertz	THz	1,000,000,000,000
Gigahertz	GHz	1,000,000,000
Megahertz	MHz	1,000,000
Kilohertz	kHz	1,000
Hertz	Hz	1
Millihertz	mHz	0.001

Because every step on this ladder is an exact power of ten, no SI-prefix conversion loses information. Two and a half megahertz is exactly 2,500,000 Hz, and 2,500,000 Hz converts back to exactly 2.5 MHz. The same logic holds for any prefix pair: a value entered in kHz and read out in GHz, or vice versa, closes the loop with no intermediate rounding.

How to convert a frequency in three steps

The fastest way to get an accurate frequency conversion is to enter the value once, choose the two units, and read the answer. The Frequency Converter handles the rest of the arithmetic in the background.

Type the frequency you want to convert into the frequency value field on the Frequency Converter.
Choose the source unit under 'From' and the target unit under 'To' — Hz, kHz, MHz, GHz, THz, mHz, rpm, BPM, rad/s or deg/s.
Read the converted result instantly, or tick 'Show all units at once' to see every unit from millihertz to terahertz alongside rpm, BPM, rad/s and deg/s.

To verify the result, copy the converted value back into the field, swap the 'From' and 'To' selections to return to the original unit, and confirm the answer matches your starting number. Round-trip matching is the simplest way to confirm the tool's accuracy, and it works because the underlying constants are exact. Common use cases span audio and music (Hz, BPM), radio and wireless (kHz, MHz, GHz), processors and signal timing (MHz, GHz), light and spectroscopy (THz), and rotating machinery (rpm, rad/s).

Worked example: 440 Hz to kHz and back

Standard concert-A pitch sits at 440 Hz, the reference frequency used to tune instruments. To express that in kilohertz, divide by 1000: 440 ÷ 1000 = 0.440 kHz. To verify the conversion, take 0.440 kHz and multiply by 1000: 0.440 × 1000 = 440 Hz. The round trip closes exactly, which confirms the Hz-to-kHz conversion is precise. Because the same logic applies to every SI-prefix pair, a value entered in MHz can be read out in GHz, THz, or mHz with no loss of accuracy.

Angular frequency and rad/s: where precision matters

Angular frequency is the unit where most converters get the constant wrong. Angular frequency (omega) is the rate at which a rotating or oscillating object sweeps through radians, while ordinary frequency f counts complete cycles per second. Because one full cycle sweeps 2π radians, omega = 2π·f, so 1 Hz equals exactly 2π rad/s, which is approximately 6.283185 rad/s. Going the other way, 1 rad/s = 1/(2π) Hz, which is approximately 0.159155 Hz. The Frequency Converter uses 2π exactly rather than a rounded 6.2832, so a round trip through Hz to rad/s and back returns your original number with no drift. Notice the magnitude relationship — a rad/s number is roughly 6.28 times larger than the same frequency written in Hz, so 1 rad/s describes a slower cycle than 1 Hz even though the digits look smaller.

Degrees per second follow the same idea with a full turn of 360 degrees, giving 1 deg/s = 1/360 Hz, which is approximately 0.002778 Hz. Because 360 is an integer, the deg/s conversion closes exactly when you multiply and divide by the same factor. Together, rad/s and deg/s let you move between trigonometric math and ordinary frequency without losing precision, provided the converter relies on exact constants rather than approximations.

Revolutions per minute and beats per minute are per-minute rates, and both convert to Hz with the same one-line formula: divide by 60. That makes 1 rpm = 1/60 Hz, approximately 0.016667 Hz, so 60 rpm equals 1 Hz and 3000 rpm equals 50 Hz. BPM uses identical numbers — 60 BPM equals 1 Hz and 120 BPM equals 2 Hz — but the label tells you which world the value comes from. RPM describes a spinning motor, hard drive, or engine, while BPM describes musical tempo or heart rate. Because the converter keeps rpm and BPM as separate units, you can move between a drummer's tempo, a motor's speed, and a clean hertz reading without redoing the arithmetic.

The 60 ratio is rational and integer-based, so the conversion is exact: any value in rpm multiplied by 60 returns the same number when divided by 60. This is one reason why mechanical speed references such as 3000 rpm (a typical small motor speed) and musical references such as 128 BPM sit so close to clean Hz values — the math keeps them aligned by a factor of 60.

Verify your conversion with a round-trip check

The simplest way to confirm any frequency conversion is correct is to convert the answer back to the starting unit and see whether the value matches. With SI prefixes, this is automatic: if 2.4 MHz converts to 2400 kHz, then 2400 kHz converts back to 2.4 MHz. With rad/s, the round trip returns the same Hz only if the converter uses 2π exactly rather than a rounded 6.2832. With rpm and BPM, dividing by 60 then multiplying by 60 closes the loop exactly because 60 is an integer and the inverse 1/60 is rational.

If you ever spot a mismatch, the cause is usually one of three things: a converter that rounds intermediate values, a constant that has been approximated (especially 2π for rad/s), or a unit treated as 1/100 or 1/10 of the next unit by mistake. The Frequency Converter uses exact constants and full client-side math, so round-trip checks pass for every supported pair. Everything runs in your browser, so the values you enter never leave your device — accuracy stays exact while the inputs stay private.