Simple Trick to Convert Volatility

My boss came to me today with "how do I convert this monthly vol to annual?". This is by far not the first time someone asked me to convert x-period volatility to y-period volatility. If you're having troubles doing this, here is a simple trick to remember: figure out the multiplier as if scaling were linear, and take the square root of that multiplier. For example, returns scale linearly with time. If someone gives you a monthly returns to convert to annual, you would simply multiply it by 12. So, in the case of converting monthly to annual volatility multiply it by √12. If someone gives you annual returns and asks you to calculate daily returns you would divide it by 252. To convert annual volatility to daily volatility divide it by √252.

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P.S. √252≈16, which is the reason for "rule of 16" for converting daily to annual volatility.
P.P.S. To convert:

Daily to weekly	->	multiply by √5
Daily to monthly	->	multiply by √21
Daily to quarterly	->	multiply by √63
Daily to annual	->	multiply by √252
Weekly to daily	->	divide by √5
Weekly to monthly	->	multiply by √4
Weekly to quarterly	->	multiply by √12.5
Weekly to annual	->	multiply by √50
Monthly to daily	->	divide by √21
Monthly to weekly	->	divide by √4
Monthly to quarterly	->	multiply by √3
Monthly to annual	->	multiply by √12
Quarterly to daily	->	divide by √63
Quarterly to weekly	->	divide by √12.5
Quarterly to monthly	->	divide by √3
Quarterly to annual	->	multiply by √4
Annual to daily	->	divide by √252
Annual to weekly	->	divide by √50
Annual to monthly	->	divide by √12
Annual to quarterly	->	divide by √4