Considering the income, around 15-20%, most likely, in the US.

Would be around 10% in Canada, though.

I normally pay around 35 % for taxes and insurances (germany). But the more I earn, the more I have to pay. When I earn 2.000 bucks in a month, I just pay around 500 € for taxes and insurances. But When I earn 6.000 €, I'll have to pay around 2.500 € for that stuff.

It all depends however, because the exact amount is being calculated by What I earn in a year. But those numbers are my experience After working for almost 7 years as a freelancer. But When you ask about payment by the hour, I always calculate with around 33 % for taxes and insurances.

The German state takes more than 40% of your wage for government social security alone, followed by a progressive income tax.

https://en.wikipedia.org/wiki/Social_security_in_Germany#Funding

Now, that's an exaggeration, do re-read that link.

I don't think it's fully fair to consider pension in the calculation, seeing as it is essentially a (mandatory) savings account for yourself (the amount you receive back is directly proportional to the amount you put in.)

Consider, also, that the amounts stated to come from the employer are not stated on the income. Something similar also exists in the US - health insurance, for example, is also offered by employers, in many (most) cases, in Germany, it's just declared to be mandatory, and going through the state.

I'm a freelancer, so I don't pay for social security.

Careful when explaining stuff like this because many, many people do not realize that the progressive tax system brackets are intended so that only the money ranging in each bracket is taxed at that rate. So for example, if the hypothetical first bracket was from $1-$30,000 and was 10% then $30,000 would be taxed at 10% and the remaining amount ($1200 using your example) would be taxed at the next highest bracket rate (15%).

There is never, never, a case where you would be better off earning less money. Many people do not realize that. You are not better off if you earn $29,999 compared with $30,001 when it comes to taxes.