Self employed and moved to UK in mid 2017, can i pay all 2017 tax to US?

I moved to the UK in May last year while continuing my work as a freelancer, am I able to pay up all of 2017 taxes with just the US and start 2018 with the UK? I'm asking because I have a nice chunk of US dollars still in the states that I'd rather just pay everything with and not have to convert if possible.

While you can pay what you like to the IRS, if you have not already paid HMRC, you will owe UK tax & NIC on the taxable profits for the 2017-18 UK tax year that relate to the period after arrival in the UK. 

Is arrival defined as the day I land, the day I got my National Insurance Number (which was 2 months later) or can I actually define it as whatever day I want? I know I probably sounds like I'm doing something shady, but I've had my spousal visa for awhile and my wife already owned the apartment so there isn't anything specific that points to when I technically moved here. I didn't bill my clients from one address and then change to a different address on a certain day either, it's always just been the same bank account.

Is arrival defined as the day I land, the day I got my National Insurance Number (which was 2 months later) or can I actually define it as whatever day I want?

The UK tax year starts in April, and according to your title, you arrived in May. That's roughly 10 out of 12 months in the UK minimum. Tax residence isn't determined by which day you arrived but by how many days you have been resident in the UK during the past tax year.

Start with this chart. It would seem the answer to the first 3 lines, for you, is NO.
https://home.kpmg.com/content/dam/kpmg/pdf/2016/01/statutory-residence-test-flowchart.pdf

Here's the official version of the residence test:
https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/547118/160803_RDR3_August2016_v2_0final_078500.pdf

Those resident must work out how they wish to pay the UK tax:
https://www.gov.uk/tax-foreign-income

Since you're self employed, here are the additional rates for NIC:
https://www.gov.uk/self-employed-national-insurance-rates

You'll be required to keep records and will want to produce accounts each year once you have selected your business accounting date. You may want to simplify things by selecting a 31 December year-end. The business is treating as commencing the day you became UK tax resident.

I would add the following comments to those of theOAP and Guya.

For the period from May 2017 you need to look at the split year rules. See the guidance starting at paragraph 5.30 of HMRC’s SRT publication. It is likely that you will end up being treated as being UK resident (and therefore liable to UK tax) for the period from your arrival in May 2017 to 5 April 2018, under the split year rules. This is as contrasted to being UK resident from 6 April 2017 to 5 April 2018.

You need to register as self employed and for self assessment, for which you need a National Insurance number and a Unique Tax Refence. It can take some time to obtain these, so you should start now if you do not already have a NINO and UTR. There are also time limits by which you need to have registered, after which you will be liable to penalties.

You should also familiarise yourself with the cycle of UK tax payments and requirements to make payments on account.

You will need to calculate your profits in sterling terms.

Once you have got to grips with the above, you would then wish to look at the implications for US tax, and in particular the FEIE.

Thanks all for your input. As you can probably tell I've procastinated on this issue quite a bit and it's all catching up to me now that april 15th is closing in. Would you suggest I just submit a US tax return with money earned up until may of last year, and then wait until I do UK taxes later on to inform them of what I paid the UK for the remainder of the year?

Thanks all for your input. As you can probably tell I've procastinated on this issue quite a bit and it's all catching up to me now that april 15th is closing in. Would you suggest I just submit a US tax return with money earned up until may of last year, and then wait until I do UK taxes later on to inform them of what I paid the UK for the remainder of the year?

There is no filing deadline on 15 April. There is a payment due by 17 April should you wish to pay the IRS with an extension by that date.

As you paid zero tax to HMRC by 31 December 2017 there is no foreign tax credit to claim at present for 2017. You may be able to amend the 2017 return next year should the 2018 US return result in excess foreign tax credits.

I'm in the same position as you (moved in May, self-employed) and had to register as self-employed with HMRC to get taxed, even though most of my clients are based in the US. This year I have to file in the US and UK, but next year my accountant says I'll be able to file remittance for US taxes under the treaty. Make sure you're outside of the US at least 330 days from now on to qualify, as well as avoid the ACA penalty.

The remittance basis is UK domestic law. Which Article of the treaty changes both that and the argument held in ''Ogilvie v Kitton'' (case law from 1908) to allow self-employment to be taxed on the remittance basis?

I concur with Guya’s comments in relation to AncestrySpouse’s reference to the use of the remittance basis.

Under UK domestic law the remittance basis in available to a UK resident non-domiciled sole trader only if the trade is carried on wholly outside the UK. This would not be the case if for instance AncestrySpouse provided advisory services from the UK.

Article 7 of the UK US double tax treaty deals with the taxation of Business Profits. There is nothing in that Article, or elsewhere in the treaty, that would deem a trade of a UK resident to be carried out wholly outside the UK.

Perhaps AncestrySpouse would like to check with the adviser and comment further?

I think I might have misspoken or used the incorrect term. What my accountant was saying is that I'm not likely to owe taxes in the US under the tax treaty between the US and UK for the 2018 tax year, since my income is unlikely to be more than the US-UK tax treaty. I'll just file in the US and indicate the income was already taxed in the UK.

For the 2017 tax year I don't qualify for the treaty, since I didn't move to the UK until May 2017 and worked in the US in the first part of the year.