I have applied for a K1 Visa to join my fiance (US citizen) in the US later this year.
I am planning to move to the US on the 15 December. We will get married in January 2019 and I hope to receive a green card in March 2019. Given that the K1 visa is a non immigrant visa, it is unclear to me whether I will be considered US tax resident from the time I arrive in the US or from the day I receive agreen card. This is important for me to know because I will receive income from the country I currently reside in after i move to the US (a redundancy payment in January & bonus in March). I will not be allowed to work in the US before I receive the green card, it seems a litle harsh that I am considered tax resident before I'm allowed to work.
For 2018 you would be a nonresident alien and would only have to report US source income.
For 2019, assuming you will receive the green card and will be in the US January 1st 2019, you will be considered a resident alien for the entire year and will need to report worldwide income. Since you will be married, you can file a joint return. If you pay taxes in the foreign country for your income from that country, you can use the foreign paid tax credit to offset those taxes, you will not have to pay double taxes, but if the tax rate in the US is higher, you will need to pay the difference between the tax credit and the tax due in the US.
Thank you for your answer. I understand that the reason for this is that in 2019, I will meet both the green card test and the substantial presence test.
This is going to be very costly, because I come from a country with much lower taxes than the US.
Thanks for your help!