Do I need to be proactive about telling the tax man (HMRC) I earn more than the child benefit threshold?
unregister for child benefit but apparently If I do that then my wife will stop getting the automatic national insurance stamp each year and will lose years of state pension You probably got this wrong according to Citizen's Advice. You can choose not to receive any Child Benefit, if you don't want to pay the extra tax. However, HMRC is encouraging you to still fill out a Child Benefit claim form even if you choose not to actually receive any Child Benefit payments from them. This is because filling your claim form for Child Benefit can help you build up national insurance credits which can help protect your future state pension. This is particularly important if you've stopped work to look after children full time. It can also help protect your entitlement to other benefits such as Guardian's Allowance, and ensure your child is automatically issued with a National Insurance number before their 16th birthday. Completing a Child Benefit claim form will make it easier for payments to start again if your circumstances change and your income falls below the £50,000 limit. As for Self Assessment If you decide to continue getting Child Benefit, you'll have to fill in a self-assessment tax return. This is when you'll have to declare you were getting Child Benefit and pay the extra tax, known as the High Income Child Benefit Charge. You'll have to register for self-assessment if you are not already registered. You can choose to pay the tax charge either: The following is important though:-   It is your responsibility to pay the extra tax, even if you don't hear from HMRC. SOURCE
You can register a limited company and leave it dormant, that's no problem. You just need to make sure that later on you notify HMRC within 3 months of any trading activity. As pointed out, you can register a company in a few hours now so I wouldn't worry about that. Your confusion about Private Limited Companies is understandable, it's often not made clear but UK formation services standard packages are always Private Limited by Shares companies. Limited by Guarantee is something else, and normally used by charities or non-profits only. See explanations here. Registering for VAT is optional until you reach the £81,000 turnover threshold but it can make your services more attractive to large companies - especially in your field of business. You should really seek professional advice on whether or not this is the best option for you. You need to set your status as self-employed the day you started online work. If that date is a little ambiguous (as is usually the case with online business), you can start with the day you first made any money. Yes, you can deduct expenses from your revenue. But you have to be sure that the expenses were purely business related.  This is how it goes: You inform HMRC about the day you started work. HMRC will assign you a UTR (Unique Tax Reference) number. Depending on how much you make you might or might not need to pay Class 2 NI contributions. You'll need to tell HMRC how much you expect to earn in the current tax year. Finally, you'll need to complete a Self-Assessment at the end of the tax year. I highly recommend setting up a business banking account. Here is a link that discusses being part-time self-employed in the UK. "Not really, no. The assumption you're making—withdrawals from a corporation are subject to ""[ordinary] income tax""—is simplistic. ""Income tax"" encompasses many taxes, some more benign than others, owing to credits and exemptions based on the kind of income. Moreover, the choices you listed as benefits in the sole-proprietor case—the RRSP, the TFSA, and capital gains treatment for non-registered investments—all remain open to the owner of a small corporation ... the RRSP to the extent that the owner has received salary to create contribution room. A corporation can even, at some expense, establish a defined benefit (DB) pension plan and exceed individual RRSP contribution limits. Yes, there is a more tax-efficient way for small business owners to benefit when it comes time to retirement. Here is an outline of two things I'm aware of: If your retirement withdrawals from your Canadian small business corporation would constitute withdrawal from the corporation's retained earnings (profits), i.e. income to the corporation that had already been subject to corporate income tax in prior years, then the corporation is able to declare such distributions as dividends and issue you a T5 slip (Statement of Investment Income) instead of a T4 slip (Statement of Remuneration Paid). Dividends received by Canadian residents from Canadian corporations benefit from the Dividend Tax Credit (DTC), which substantially increases the amount of income you can receive without incurring income tax. See TaxTips.ca - Non-eligible (small business) dividend tax credit (DTC). Quote: For a single individual with no income other than taxable Canadian   dividends which are eligible for the small business dividend tax   credit, in 2014 approximately $35,551 [...] could be earned before   any federal* taxes were payable. * Provincial DTCs vary, and so combined federal/provincial maximums vary. See here. If you're wondering about ""non-eligible"" vs. ""eligible"": private small business corporation dividends are generally considered non-eligible for the best DTC benefit—but they get some benefit—while a large public corporation's dividends would generally be considered eligible. Eligible/non-eligible has to do with the corporation's own income tax rates; since Canadian small businesses already get a big tax break that large companies don't enjoy, the DTC for small businesses isn't as good as the DTC for public company dividends. Finally, even if there is hardly any same-year income tax advantage in taking dividends over salary from an active small business corporation (when you factor in both the income tax paid by the corporation and the individual), dividends still allow a business owner to smooth his income over time, which can result in a lower lifetime average tax rate. So you can use your business as a retained earnings piggy bank to spin off dividends that attract less tax than ordinary income. But! ... if you can convince somebody to buy your business from you, then you can benefit from the lifetime capital gains exemption of up to $800,000 on qualifying small business shares. i.e. you can receive up to $800K tax-free on the sale of your small business shares. This lifetime capital gains exemption is a big carrot—designed, I believe, to incentivize Canadian entrepreneurs to develop going-concern businesses that have value beyond their own time in the business. This means building things that would make your business worth buying, e.g. a valued brand or product, a customer base, intellectual property, etc. Of course, there are details and conditions with all of what I described, and I am not an accountant, so please consult a qualified, conflict-free professional if you need advice specific to your situation." In general no, if you just have one employer and work there with the same salary for the whole year.  Typically an employer does tax withholding by extrapolating your monthly income to the entire year and withholding the right amount so that at the end, what is withheld is what you owe.  It's not a surprise to them when your income crosses a tax bracket threshold, because they knew how much they were paying you and knew when you would cross into another bracket, so they factored that in. If you have multiple jobs or only worked for part of the year, or if your income varied from month to month (e.g., you got a raise) there could be a discrepancy between what is withheld and what you owe, because each employer only knows about what it's paying you, not what money you may have earned from other sources.  (Even here, though, the discrepancy wouldn't be due to the tax brackets per se.)  You can adjust your withholdings on form W-4 if needed, to tell the employer to withhold more or less than they otherwise would. "I don't think it really matters, my understanding is that as a sole trader there is no distinction between your personal and business tax affairs. The distinction between your personal and business account is mainly for your own personal benefit to make it easier to differentiate between ""wages"" and retained earnings. If you want to maintain this distinction with regard to tax then you need to somehow differentiate between tax paid on your ""wage"" and tax paid on retained earnings. You could then either make two payments, or pay from either and transfer the difference from the other. Either way, it's just a matter of perspective rather than something with a physical difference." Aside from the fact that probably nobody is ever going to come and ask for that proof unless your amounts get five digits (or you're unlucky), if you never before reimbursed yourself, your old tax declarations would clearly show that. You can't prove a negative, so the only potential is that you had reimbursements before, and an audit might ask you to prove that the new ones are not duplicates of those. In this case, if you have other receipts / proof for all those other reimbursements, they are obviously not duplicates. "OK, it's a bit of a minefield but here goes! You only pay corporation tax in the UK on any profit made, so your ""salary"" would not be classed as part of the profit, so in the example you give you would only pay corporation tax on £4k less your ""salary"" ie £3,200 so profit on the £800 remaining gross profit. You don't say if your figures are monthly, annual etc, but you only pay income tax if you earn over £11.5k in any given tax year, the rates increase as your income does, check here:  https://www.gov.uk/income-tax-rates You may have a different tax code, you would need to check that with HMRC but the link gives the ""default"" position which is correct for most people. https://www.itcontracting.com/limited-company-dividends/ If the figures you give are monthly then I would consult an accountant as they are likely to save you more than they will charge for their services. You will probably find it is most tax efficient to pay yourself a dividend from the company's profits but check with an accountant. More info: https://www.gov.uk/running-a-limited-company/taking-money-out-of-a-limited-company" "In the US, you'd run the risk of being accused of fraud if this weren't set up properly.  It would only be proper if your wife could show that she were involved, acting as your agent, bookkeeper, etc. Even so, to suggest that your time is billed at one rate but you are only paid a tiny fraction of that is still a high risk alert.  I believe the expression ""if it quacks like a duck..."" is pretty universal. If not, I'll edit in a clarification.  note -I know OP is in UK, but I imagine tax collection is pretty similar in this regard."