1) if you are "self employed" and just do "boletas" (a sort of personal invoice), you pay 10% of that each month as a provision of your total income tax, usually this is paid directly by the receiver of the invoice to the SII (chilean equivalent of the IRS)
2) if you have an employment contract from a company, the company pays whatever the corresponding tax is for what they are paying you each month directly to the SII
But, each year you have to file a tax declaration form with the SII. And depending on the total amount that you earned during the year, there's a corresponding tax rate that you have to pay. Then if the total amount of the provision you paid during the previous year is higher than what you had to pay, you get a return on the difference (adjusted for inflation), but if the corresponding rate is higher (10% in your case), you'll have to pay the SII the difference.
If you only have one employment contract, from one company, then your total tax (global complementario) has already been paid, and you are excused from having to file your tax declaration.
Here's the table for the tax (global complementario) you have to pay corresponding to your total income:
The way the table works is kind of complicated, the tax rate you have to pay depends on the total amount, but you have to pay a different rate for each of the tax brackets/tiers that your total earnings fall in. There's also a maximum total discount that you can subtract from the total as "expenses". The total is easy to calculate from the table using the "cantidad a rebajar" (discount) column though.
For example, if you make Ch$ 15 M (around USD 30k) a year, then you have to pay (according to the table above), 10% of: Ch$ 15 M, minus the discount on the same row = Ch$ 1.5M - 900k = Ch$ 600k. Hence, if you paid Ch$ 1.5M in provisions during the previous year, you'll get a Ch$ 900k (about USD 1.8k) return.
There's also another discount for expenses, I don't fully understand how it works though, but it would mean paying even less in the example above, and getting a higher return.
I'm not an accountant though, so don't take my word for it and get well informed before filing a tax return form.
Edit: changed some wording for clarity, added some info and changed the link to a more current table
1) if you are "self employed" and just do "boletas" (a sort of personal invoice), you pay 10% of that each month as a provision of your total income tax, usually this is paid directly by the receiver of the invoice to the SII (chilean equivalent of the IRS)
2) if you have an employment contract from a company, the company pays whatever the corresponding tax is for what they are paying you each month directly to the SII
But, each year you have to file a tax declaration form with the SII. And depending on the total amount that you earned during the year, there's a corresponding tax rate that you have to pay. Then if the total amount of the provision you paid during the previous year is higher than what you had to pay, you get a return on the difference (adjusted for inflation), but if the corresponding rate is higher (10% in your case), you'll have to pay the SII the difference.
If you only have one employment contract, from one company, then your total tax (global complementario) has already been paid, and you are excused from having to file your tax declaration.
Here's the table for the tax (global complementario) you have to pay corresponding to your total income:
http://www.sii.cl/pagina/valores/global/igc2011.htm
The way the table works is kind of complicated, the tax rate you have to pay depends on the total amount, but you have to pay a different rate for each of the tax brackets/tiers that your total earnings fall in. There's also a maximum total discount that you can subtract from the total as "expenses". The total is easy to calculate from the table using the "cantidad a rebajar" (discount) column though.
For example, if you make Ch$ 15 M (around USD 30k) a year, then you have to pay (according to the table above), 10% of: Ch$ 15 M, minus the discount on the same row = Ch$ 1.5M - 900k = Ch$ 600k. Hence, if you paid Ch$ 1.5M in provisions during the previous year, you'll get a Ch$ 900k (about USD 1.8k) return.
There's also another discount for expenses, I don't fully understand how it works though, but it would mean paying even less in the example above, and getting a higher return.
I'm not an accountant though, so don't take my word for it and get well informed before filing a tax return form.
Edit: changed some wording for clarity, added some info and changed the link to a more current table