A missed deadline can turn an otherwise good month in business into an unexpected bill. For new founders, startup tax deadlines often arrive before routines are in place: a first payroll run, a VAT quarter, a Corporation Tax payment or the January Self Assessment rush. The good news is that most deadlines are predictable once you know which taxes apply to your business and keep your records up to date.
The dates below are a practical guide for UK start-ups, sole traders and limited companies. Your exact obligations depend on your business structure, turnover, employees and whether you work in construction, so use them as a working calendar rather than a one-size-fits-all checklist.
Startup tax deadlines: start with your business structure
A sole trader and a limited company can have very different filing dates, even when they provide the same service. Sole traders generally report business profits through Self Assessment. Limited companies have Corporation Tax responsibilities, annual company accounts and potentially Self Assessment too if the director receives dividends or has other untaxed income.
If you employ anyone, including yourself as a director paid through payroll, you will also have PAYE deadlines. Registering for VAT creates another regular timetable. Construction businesses paying subcontractors may need to deal with CIS each month.
Trying to remember every date in your head is rarely the best approach. Put the deadlines that apply to you in a shared calendar, allow time beforehand to check the figures, and keep a clear record of what has been filed and paid. This is far less stressful than reacting to reminder letters.
Self Assessment dates for sole traders and directors
The tax year runs from 6 April to 5 April. If you are newly self-employed and need to submit a Self Assessment tax return for the first time, you normally need to tell HMRC by 5 October following the end of the tax year in which you started trading.
For example, if you began working as a sole trader during the tax year ending 5 April 2026, you would usually register for Self Assessment by 5 October 2026. Waiting until January is a common mistake and can leave little time to get your records in order.
The key Self Assessment deadlines are:
- 31 October following the end of the tax year for a paper return.
- 31 January following the end of the tax year for an online return.
- 31 January for any balancing tax payment due for the previous tax year.
- 31 July for the second payment on account, where payments on account apply.
Payments on account can catch new business owners out. HMRC may ask you to make advance payments towards the following year’s bill if your last Self Assessment bill was more than £1,000 and less than 80% of your tax was collected at source. Your first payment is due on 31 January alongside the balancing payment, with the second due on 31 July.
This does not mean you are being taxed twice, although it can feel that way in your first profitable year. It is an advance towards the next bill. If you know your income will be lower, you may be able to reduce payments on account, but only do this where there is a genuine reason. Reducing them too far can lead to interest later.
Limited company directors may still need Self Assessment
Running a limited company does not automatically remove your personal tax return. You may need to file one if you receive dividends above the relevant allowance, have income outside PAYE, are a higher-rate taxpayer, or HMRC asks you to do so. Keep dividend vouchers, payroll records and details of any other income together throughout the year. It makes January much more manageable.
Corporation Tax and company accounts deadlines
Once a limited company starts trading, it must register for Corporation Tax, usually within three months of beginning business activity. Starting activity can mean selling goods or services, buying stock, advertising, employing someone or earning interest. Incorporating a company and actually beginning to trade are not always the same thing.
Your company pays Corporation Tax on its taxable profits. The two deadlines that matter most are different:
- Corporation Tax is normally paid nine months and one day after the end of your accounting period.
- The Company Tax Return is normally filed 12 months after the end of that accounting period.
If your accounting year ends on 31 March, your Corporation Tax payment will generally be due by 1 January the following year, while the tax return is due by 31 March. Filing the return is not the same as paying the tax, so do not wait for the filing deadline before setting money aside.
Company accounts also need filing with Companies House. For most private limited companies, accounts are due nine months after the financial year end. A confirmation statement is separate again and is usually due within 14 days of the end of the review period. Neither is a tax return, but both carry filing responsibilities and should sit in the same compliance calendar.
For a new company, the first accounting period and first filing dates can be longer or slightly different. Check the dates shown in your Companies House and HMRC correspondence rather than assuming your first year follows the standard pattern.
VAT return deadlines and Making Tax Digital
You must register for VAT when your taxable turnover exceeds the registration threshold, currently £90,000 over a rolling 12-month period. This is not based on the calendar year or your year-end. A business can cross the threshold in the middle of a busy month, which is why regular sales monitoring matters.
Some businesses choose voluntary VAT registration before reaching the threshold. This can be useful where clients are VAT registered or where you have significant VAT on costs to reclaim. However, it also means charging VAT, keeping digital records and filing returns, so it is worth considering the administrative impact as well as the cash-flow benefit.
Most VAT-registered businesses file quarterly returns. The VAT return and payment are usually due one month and seven days after the end of the VAT accounting period. For a quarter ending 31 March, that normally means a deadline of 7 May.
VAT returns must generally be submitted through Making Tax Digital-compatible software. Your bookkeeping needs to be current enough for the figures to be reliable when the deadline approaches. Leaving bank reconciliation and receipts until the final week makes errors much more likely and gives you little time to query anything unusual.
Different VAT schemes, including annual accounting and the Flat Rate Scheme, can change how often you file or how you calculate the amount due. The payment deadline still needs close attention, particularly where VAT collected from customers has not yet reached your bank account.
PAYE, payroll and CIS deadlines
If you employ staff or run a director’s salary through payroll, you need to report pay and deductions to HMRC each time you pay someone. A Full Payment Submission, often called an FPS, must be sent on or before payday. This applies even if you only have one employee.
PAYE tax and National Insurance payments are usually due by the 22nd of the following tax month when paid electronically. Tax months run from the 6th of one month to the 5th of the next, which is easy to overlook. For example, deductions from pay between 6 April and 5 May are normally due by 22 May.
At the end of the payroll year, give employees their P60 by 31 May. If you provide taxable benefits, P11D forms are generally due by 6 July, with any Class 1A National Insurance normally due by 22 July when paid electronically.
Construction businesses operating the Construction Industry Scheme have an additional monthly return. CIS returns are usually due by the 19th of the month after the tax month, and deductions paid to HMRC by the 22nd if paying electronically. Verify subcontractors before paying them and keep clear records of deductions. Small errors can quickly become time-consuming to correct.
Build a calmer routine around your deadlines
Tax deadlines are easier to meet when the information behind them is already organised. Set aside a regular time each week to raise invoices, reconcile your bank account, upload receipts and check what you owe. If your income is seasonal, move money into a separate tax savings account when payments arrive rather than relying on whatever is left at the deadline.
A monthly review is also a sensible time to look ahead. Check your VAT position, payroll costs, upcoming Corporation Tax and whether late-paying customers could affect your ability to pay HMRC on time. Good records do more than support compliance. They show you what the business can safely afford.
If a deadline is approaching and your records are incomplete, act early. HMRC may charge penalties and interest for late filing or payment, but leaving the issue until after the due date rarely improves the outcome. A bookkeeper or accountant can help establish what is outstanding and create a practical plan.
At Angel Bookkeeping & Payroll Services, we see the difference a simple, dependable timetable can make for a growing business. The aim is not to make you a tax expert. It is to give you clear numbers, on-time submissions and the confidence to focus on the work that moves your business forward.