The Life You Can Save VS. 10% Pledge

Hi,

I’m new to effective altruism and just got my first paycheck from my job.

I’m confused.

On one hand, The Life You Can Save offers a calculator on how much to donate. It seems to be a pretty progressive calculator in the sense that the more money you make, the higher “tax” you pay.

Furthermore, it seems pretty clear that the tax you pay is based on pre-taxed money.

What I am confused is on is that is there a progressive “tax” scheme for this 10% pledge?

It seems a bit unclear whether you are supposed to donate only 10% whether you are extremely poor or like a billionaire.

Furthermore, it is kind of ridiculous to expect poor people to donate a similar portion to a billionaire.

Finally, does the 10% pledge apply to pre-annual tax income or post-annual tax?

How would you calculate your post-annual tax income by the way if you know your hourly rate?

To calculate pre-annual income I just do : (Hourly Rate) x 40 hours x 52 weeks.

Finally, why are there two different schemes?

Is one scheme meant for one people and the other meant for others?

Isn’t Peter Singer involved with both 10% pledge and the Life You Can Save?

How does the Life You Can Save remotely related to 10% pledge?

Thanks.