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JobYour business
- Develop the ideadone
- Test your idearunning
- Start a businessnext
Required Register for Self Assessment with HMRC by 5 October after the tax year in which your side income passed £1,000.
A module of the digital founding companion for the United KingdomA planix founding-companion module
Start your own business.
And keep your job.Start on the side.
Keep your job.
- Fits your week: planix plans with the time and budget you have next to your jobFits your week
- Test first: a concept test shows whether there is anything in your ideaTest first, then invest
- Registered correctly: Self Assessment, National Insurance and VAT – with official sourceHMRC and tax sorted
All three modules freeno subscription, no credit cardno subscription
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STARTUPS
How to start in the UK
What a side business involves Five steps. Handing in your notice is not one.
Check first, then register. Your job stays as long as you want.
Check first, then register.
- FirstRead your contract
What your employment contract says about side work – before your first customer.
What your contract says.
- With planixSharpen the idea
What you sell to whom – with the time and budget you have next to your job.
With your time and budget.
- With planixTest
A concept test shows whether there is anything in it before you invest money.
Before you invest.
- RequiredRegister with HMRC
Self Assessment once your side income passes £1,000 a year – by 5 October after that tax year.
Self Assessment with HMRC.
- LaterGrow
Your job stays until your business carries you. You choose the moment.
Job stays until it carries.
Your profit is added to your salary and taxed at your highest Income Tax band – in Scotland at the Scottish rates.
A side business in the UK
Three numbers you should know.
From the planix fact table – with authority and date.
With authority and date.
Up to this much side income per tax year is tax-free. Above it, you register for Self Assessment.
Tax-free up to here.
HM Revenue and Customs (HMRC) · GOV.UK guidance ‘Tax-free allowances on property and trading income’ (HM Revenue and Customs (HMRC)), gov.uk, as of 06.04.2017Only once your taxable turnover over the last 12 months passes this do you have to register for VAT.
VAT only from this turnover.
HM Revenue and Customs (HMRC) · GOV.UK guidance ‘Register for VAT’ (HM Revenue and Customs (HMRC)), gov.uk, as of 10.10.2024On profits from £12,570 to £50,270, paid through Self Assessment – on top of the NI on your salary.
On profits, via Self Assessment.
HM Revenue and Customs (HMRC) · GOV.UK guidance ‘Self-employed National Insurance rates’ (HM Revenue and Customs (HMRC)), gov.uk, as of 06.04.2026What planix delivers
Idea. Test. Founding.
Three modules of the founder journey – evenings or weekends, at your own pace.
Target customer, problem, offer and the maths per sale on one page, with a completed canvas.
- Target customer, problem, offer
- Calculation per sale
- Business Model Canvas
- Business Model Canvas - Word
- Your idea
Your riskiest assumption tested, with a first assessment and the next validation step.
- What convinces, what doesn’t
- Questions for real conversations
- Your next step
- Your concept test
Reasoned legal form, founding roadmap and obligations for taxes and staff, with official sources.
- Legal form that fits your inputs
- Founding steps in the right order
- Tax and National Insurance, with source
- Your founding plan
Clear limits
What planix does not do.
- 1
Your employment contract is up to you. Whether you have to tell your employer about side work is in your contract. planix does not read it.
You read the contract. planix does not check it.
- 2
You register yourself. planix shows where and by when. Nothing is submitted in your name.
You register. planix shows where and when.
- 3
No invented numbers. Thresholds and deadlines come from official sources – with date.
Nothing invented. Every number with a source.
FAQ
Questions
Usually yes – you can be employed and self-employed at the same time. Whether you need your employer’s consent, or may not compete with them, is in your employment contract. Read it before you start.
Yes, once you earn more than £1,000 from self-employment in a tax year (6 April to 5 April). You register for Self Assessment by 5 October after the end of that tax year. You need your National Insurance number for it.
As much as you have. In «Develop the idea» you state how much time and budget you have – planix plans with it. You can pause and continue at any time.
Only once your taxable turnover over the last 12 months passes £90,000. Below that, registering is voluntary – for example to reclaim VAT on your costs.
Develop the idea free, Test the idea free, Found your company free – no subscription.
When your business covers your living costs – you decide. «Business & financial planning Pro» calculates the numbers: is the profit enough for your household?
Start on the side?
Begin tonight.
The idea first. Test and registration when you’re ready.
Start for free All three modules free · no subscription