Hi!
why is everyone telling me that I should not use more than 1% on a single trade?
I mean -when I have a $5,000 account and risk 10%, that would be like $500…
so when I have a $50,000 account and I risk 1%, that would be like $500, too…
so what’s the deal? do you want me to use the 99% as usable margin when something goes wrong? 
regards
PS:
might be that I got something completely wrong - I’m quite a noob
I am a complete Newbie too, but I think I can answer this, as I understood it from the babypips school (which I need to do again, because I have forgotten a lot).
They say that one of the major reasons for failure is undercapitalisation.
You should only risk 1% because even if you have are the best trader in the world the market may turn sour, then you a few bad trades in a row, maybe even six or seven, heaven forbid.
If you are risking 10% (doesn’t matter whether you have a $5000 or $50000 account) if you lose a trade , you have lost 10% , then another and another, and then you have lost 30%, or more compounded.
Now to get back up is a real struggle , to get back to where you were, you have to make spectaclar percentage gains, on what you have left.
I think this is the reason.
look in school: 13th grade, money management
Drawdown and Maximum Drawdown? - 13th Grade: Money Management - Beginner’s Guide to Forex Trading, Free Forex Education, Learn to Trade Forex, Forex Training - BabyPips.com
hi
I see, thanks for your reply!
but i think in the end percentages are not important… 1% could be $0.01, $100, or $1,000,000,000… so when I have a $40,000 and a $4,000 account, why am I “allowed” to risk $400 at my $40,000 account but “disallowed” to risk $400 at my $4,000 account?
(I don’t have such accounts, and I won’t have such accounts, this is just a stupid example)
ahh, thanks for the link, great explanation 
look in school: 13th grade, money management
Drawdown and Maximum Drawdown? - 13th Grade: Money Management - Beginner’s Guide to Forex Trading, Free Forex Education, Learn to Trade Forex, Forex Training - BabyPips.com
whoops, i didn’t mean to post that again.
anyway, yes , the percentages are very important, if you lose $400 out of $40000, then you still have a lot left to play with, if you lose $400 out of $4000 it is relatively a lot more significant. the percentage is the key.
If you have $40,000,000 the you lose 10% of that a few times, it has the same relative impact on your wealth, as if it was 10% of your $4000!
To Mariomullermanno :
DoctorG is correct in what he says.
Read the Babypips section again and highlight the important parts with a highlighter pen.
Take the advice or lose your dough.!! 
It takes some time to fully understand the logic of these things. This will grow on you with time.
All the best!