Take 1-1-1900 as a starting point. That is represented in Excel as the
number 1. So Jan 2 1900 is number 2. etc.
Small error: Excel treats 1900 as a leap year. Forget that; hardly any
effect on your calculations.
So 8 years would be 1-1-1908, the number 2923. 80% of that would be May 26
1906; the number 2338.4
If you want to express that in years, months and days, look he

http://www.cpearson.com/excel/datedif.htm

--
Kind regards,

Niek Otten

"Ricardo Monteiro :^)" wrote in
message ...
Sorry, I'm getting no results. The formulas you indicated start with a
date
and I'm working with "time quantities", like 8 years, 20 years, etc.,
which
will be greater or lesser in some percentage. Is what I'm saying
understandable?

"Niek Otten" escreveu:

See

http://www.cpearson.com/excel/datedif.htm

--
Kind regards,

Niek Otten

"Ricardo Monteiro :^)" wrote
in
message ...
Cell A1 shows prison time for a certain crime (eg. 8 years).
How would cell B1 show 1/5 (20%) of that in time format (ie, not 1,6;
but
1
"year" 7 "months").
I suppose I want a duodecimal system instead of a decimal one...
Thanks in advance.