Tax is again something that you need to take very seriously, and you have obligations that extend beyond what is in the US and what is in Australia (basically, you need to combine them). Seeking professional advice, therefore, is potentially your best way forward. I have listed some accountants who have been passed through to me below, and if you have more, please do let me know!
Federal income tax, Federal Social Security and Medicare tax, State income tax, and City income tax are withheld every pay-check.
Your employer estimates how much tax you will owe at the “end of the year” (in truth, the 15th of April or the next business day following it if the 15th is a weekend or holiday) and remits this amount to the various levels of government.
In January and early February, you start receiving forms from your employer, health insurance company, bank, and any other entity that gave you money over the past year. Keep these handy. You’ll need them when you File Your Tax Return.
How do you file your tax?
As a newcomer to the U.S. (for at least the first year and first filing), you should always, for simplicity, safety and peace of mind, use a proper accounting or tax firm. This applies too if you are in a situation that is more complicated than simply working one job (e.g. with assets or international considerations). I personally recommend Robert (“Bob”) Stein from Raich Ende Malter & Co., he’s been fantastic!
After a year, most Americans use Turbo Tax, an online system like Etax in Australia (though privately run, so there’s a fee!). It’s pretty easy and cost effective and it also helps you understand what’s driving your US tax. A “tax preparer” can help you get everything in a line if you need some help.
P.S. It is worth pointing out that deductions are quite complicated in the US – but most taxpayers who don’t have mortgages use a standardized deduction, which means you do not get a tax deduction on your accountant fees. So don’t mentally deduct 40% when considering the cost!
Payroll taxes aren’t your only tax. The other big one (excluding property tax that you probably won’t directly pay since you won’t likely own property just yet) is sales tax. This is the “government markup”, shall we say. The price on the shelf is not your out-the-door price. If an item costs $10 and you live in an area with a 9.5% sales tax, you will owe the cashier $10.95. Not every area has a sales tax–notably, Oregon does not impose one anywhere in its state–and the sales tax rate varies by area. Suffice to say, prepare to pay up to 10% more than what the shelf price says in most areas of the country.
Raich Ende Malter & Co. LLP – Couldn’t recommend Robert (Bob) Stein more. He’s across everything expats and will happily go through in detail almost any queries you have! This includes business, international tax, and more.
Extra bits for Australians
It’s important to think about HECS, HELP, investments, income, and partners in Australia when doing your tax over here!
The Aussie Expat Investor is a great one for all things helpful when it comes to tax and accounting, so be sure to keep an eye on his website. You will also want to know how Aussie expats can benefit from the double taxation agreement!
Thanks also to Ross E. for fleshing out the details.