21 seconds in minutes

Conversion

21 seconds is equivalent to 0.35 minutes.^[1]

Conversion formula
How to convert 21 seconds to minutes?

We know (by definition) that: $1 \sec \approx 0.016666667 \min$

We can set up a proportion to solve for the number of minutes.

\frac{1 \sec}{21 \sec} \approx \frac{0.016666667 \min}{x \min}

Now, we cross multiply to solve for our unknown $x$ :

x \min \approx \frac{21 \sec}{1 \sec} * 0.016666667 \min \to x \min \approx 0.350000007 \min

Conclusion: $21 \sec \approx 0.350000007 \min$

21 seconds is equivalent to 0.35 minutes

Conversion in the opposite direction

The inverse of the conversion factor is that 1 minute is equal to 2.85714285714286 times 21 seconds.

It can also be expressed as: 21 seconds is equal to $\frac{1}{2.85714285714286}$ minutes.

Approximation

An approximate numerical result would be: twenty-one seconds is about zero minutes, or alternatively, a minute is about two point eight five times twenty-one seconds.

Units involved

This is how the units in this conversion are defined:

Seconds

"The second (symbol s) is the base unit of time in the International System of Units. It is qualitatively defined as the second division of the hour by sixty, the first division by sixty being the minute.[3] SI definition of second is the duration of 9 192 631 770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the caesium 133 atom. Seconds may be measured using a mechanical, electrical or an atomic clock. SI prefixes are combined with the word second to denote subdivisions of the second, e.g., the millisecond (one thousandth of a second), the microsecond (one millionth of a second), and the nanosecond (one billionth of a second). Though SI prefixes may also be used to form multiples of the second such as kilosecond (one thousand seconds), such units are rarely used in practice. The more common larger non-SI units of time are not formed by powers of ten; instead, the second is multiplied by 60 to form a minute, which is multiplied by 60 to form an hour, which is multiplied by 24 to form a day. The second is also the base unit of time in other systems of measurement the centimetre–gram–second, metre–kilogram–second, metre–tonne–second, and foot–pound–second systems of units."

Wikipedia page of seconds

Minutes

"The minute is a unit of time or of angle. As a unit of time, the minute is equal to 1⁄60 (the first sexagesimal fraction) of an hour, or 60 seconds. In the UTC time standard, a minute on rare occasions has 61 seconds, a consequence of leap seconds (there is a provision to insert a negative leap second, which would result in a 59-second minute, but this has never happened in more than 40 years under this system). As a unit of angle, the minute of arc is equal to 1⁄60 of a degree, or 60 seconds (of arc). Although not an SI unit for either time or angle, the minute is accepted for use with SI units for both. The SI symbols for minute or minutes are min for time measurement."

Wikipedia page of minutes

Footnotes

[1] The precision is 15 significant digits (fourteen digits to the right of the decimal point).

Results may contain small errors due to the use of floating point arithmetic.

Conversion

Conversion formula How to convert 21 seconds to minutes?

Conversion in the opposite direction

Approximation

Conversion formula
How to convert 21 seconds to minutes?