The short version: yes, you can run a side hustle while on maternity leave in the UK, and starting a small business or freelancing does not stop your Statutory Maternity Pay because SMP has nothing to do with other income you earn. What can trip you up is your employment contract, the Keeping in Touch day rules if you want to do paid work for your actual employer, and the very real fact that a newborn destroys your working hours far more thoroughly than anyone tells you before you have one.
If you want to go deeper on this: Do You Need to Declare Side Hustle Income to the Tax Office?.
What happens to your maternity pay if you start earning elsewhere
Let’s clear up the bit people worry about most first, because it’s the bit most blog posts get muddled. Statutory Maternity Pay is paid to you by your employer because of your relationship with that employer. It is not means-tested. Nobody at HMRC or your payroll department is checking whether you sold three candles on Etsy last Tuesday. You could set up a small copywriting business, sell handmade jewellery, do a bit of virtual assistant work for a client in another country, and your SMP keeps arriving unchanged, at roughly £187 a week for weeks 7 to 39 (the rate is reviewed every April, so check gov.uk for the exact 2026/27 figure), on top of 90% of your average weekly earnings for the first six weeks.
The confusion usually comes from mixing SMP up with benefits that are means-tested, like Universal Credit, where extra income does affect what you’re paid. If you’re on Maternity Allowance instead of SMP (this applies if you’re self-employed or haven’t been with your employer long enough to qualify for SMP), the rules around doing work for the business you claimed it under are stricter, and it’s worth reading the official guidance on maternity pay and leave before you start invoicing anyone.
The bit about your contract nobody mentions
Here’s what catches people out, and it’s got nothing to do with SMP. Most UK employment contracts include a clause about outside work or conflicts of interest, sometimes buried three pages in under a heading like “Other Employment.” Technically you’re still employed during maternity leave, even though you’re not physically at your desk, which means that clause is still live. If you work in marketing and your side hustle is freelance marketing for other small businesses, that could count as competing work depending on how your contract is worded.
I’ve had two people email me about this exact scenario in the last year. Both had contracts that said something close to “employees must not engage in any other business or employment without prior written consent from the company.” Neither had read that clause since the day they signed it, three or four years earlier. One found out her employer was fine with it as long as it wasn’t a direct competitor. The other got a slightly awkward email from HR asking her to confirm the work didn’t overlap with client accounts she managed. Nobody got sacked. But both wished they’d checked before starting, not after their manager spotted a LinkedIn post.
The fix takes ten minutes: pull out your contract, search for “other employment,” “outside interests,” or “conflict of interest,” and read what it says. If it’s vague or you’re not sure, a short email to HR saying you’re planning to do some freelance work unrelated to the business during your leave, and asking if that’s fine, closes the question and protects you if it ever comes up later.
Keeping in Touch days versus your own side project
Don’t confuse Keeping in Touch (KIT) days with your side hustle, because they’re a completely separate mechanism. You’re allowed up to 10 KIT days during maternity leave, where you can do paid work for your actual employer, whether that’s a training day, a team meeting, or covering a shift, without it ending your maternity leave or affecting your SMP for that week. Your side hustle is a different thing entirely and doesn’t use up any KIT days, because it’s not work for the employer paying your SMP. The two systems just happen to both involve the word “work” during maternity leave, which is where the confusion creeps in.
What one of my clients did in her first four months off
A woman I worked with, I’ll call her Priya because that’s not her real name, went on maternity leave from a mid-sized marketing agency in Manchester in early 2025. She’d always wanted to try freelance copywriting on the side, mostly LinkedIn content for small B2B companies, and decided maternity leave was the moment to test it, since she’d have “more time” than being back at a full-time job. That phrase, more time, is doing a lot of heavy lifting in that sentence, and it’s worth sitting with for a second.
In her first two months, working roughly five or six hours a week spread across nap times and one evening when her partner took the baby out, she landed three small clients and made £2,800 writing LinkedIn posts and short blog pieces. It worked, and for a while it looked like the dream everyone sells you about building something during maternity leave.
Then her son hit the four-month sleep regression. Naps went from 90 minutes to 20. Nights that had settled into something manageable fell apart completely. She had three clients expecting content and a baby who wouldn’t sleep long enough for her to string two sentences together, let alone write a client’s monthly content calendar. She missed one deadline, apologised, and paused two of the three contracts until she was back at work and had childcare sorted. She still earned that £2,800, and she still says it was worth doing. But she’s also the first to say the “just work during naptime” advice she’d read online assumed a baby who napped on a schedule, which hers did for about six weeks total out of a five-month leave.
How to set it up without creating a mess for yourself
- Check your employment contract for outside work or conflict of interest clauses before you take a single booking, and email HR if there’s any doubt.
- Register as self-employed with HMRC if you don’t already have a UTR number, and know that the deadline is the 5th of October following the end of the tax year in which you started trading, not the day you make your first sale.
- Open a separate bank account for the side hustle money, even a free basic one, so it doesn’t get muddled with your SMP or household spending when you come to do your tax return.
- Keep a simple spreadsheet from day one, invoice date, amount, client name, expenses. Twenty minutes a month now saves a stressful January later.
- Set a real weekly hours cap for yourself, three to five hours to start, and treat going over it as a warning sign rather than a badge of honour.
- Tell whoever is doing childcare with you, even informally, what hours you’re planning to work, so it’s a shared plan rather than something you’re squeezing in and hoping nobody notices you’ve disappeared upstairs.
Why most maternity-leave side hustles quietly die by month three
Here’s the part that doesn’t get said much, so I’ll say it plainly: the naptime-empire idea sold on Pinterest and in a lot of “mumpreneur” content assumes a baby’s schedule and your energy levels behave predictably, and for most people they simply don’t. Newborns don’t nap on a timer. Sleep deprivation isn’t a minor inconvenience, it measurably drops your working memory and decision-making, which is exactly the stuff you need for writing, pricing, client calls, or building anything from scratch. Plenty of women start a side hustle in week two of maternity leave with total sincerity and real ambition, and by week ten it’s sitting untouched, not because they lacked drive but because the maths of newborn care and focused work rarely lines up the way it does in a blog post written by someone selling a course about it.
That’s not a reason not to try. It’s a reason to plan for the version where it stalls for a month or six weeks, and to not treat that as failure. Priya’s clients weren’t lost, they were paused, and she picked two of them back up once she was six months in and sleep had improved. Building in that flexibility from the start, telling clients upfront that you’re a new parent and deadlines might shift, does more for your sanity than any productivity hack about “batching content during nap one.”
The money and tax side, in plain figures
If your side hustle earns under £1,000 in a tax year, you don’t need to register with HMRC or declare it at all, thanks to the trading allowance. Go over £1,000 and you need to register as self-employed and file a self-assessment return by 31 January following the end of the tax year, with any tax owed paid by that same date. If you’re claiming Universal Credit alongside SMP, which some families do if household income is low, self-employed earnings do need reporting monthly and will affect your payment, unlike SMP itself which doesn’t. It’s worth a quick call to the Universal Credit helpline if this applies to you, because the interaction between the two isn’t always intuitive and getting it wrong means either an overpayment you’ll have to pay back or an underpayment you didn’t need to live with.
When it makes sense and when it doesn’t
A side hustle on maternity leave makes sense if you’ve got a partner or family member covering some childcare hours, if the work is something you can pick up and put down without losing momentum (freelance writing, virtual admin, selling a product you’ve already made rather than building from zero), and if you’re doing it because you want to, not because household finances depend on it working out. It makes far less sense if it’s your only source of extra income and you’re relying on it to cover a shortfall, because the unpredictability of a newborn’s sleep and health (colds, jabs, growth spurts all eat into “free” time without warning) makes it a shaky foundation for anything you need to pay a bill.
If you’re weighing up whether to build something bigger once you’re back at work, rather than squeezing it into maternity leave, it’s a conversation worth having rather than starting in the gaps of an already exhausting year. Some of the women I’ve worked with as an AI consultant for small businesses came to me exactly six or nine months after maternity leave ended, once they had a bit more headspace and childcare in place, and that timing made the difference between panicked evening work and a plan they could stick to.
Frequently asked questions
Will starting a side hustle affect my Statutory Maternity Pay?
No. Statutory Maternity Pay is paid based on your employment with your employer and is not reduced or stopped because you earn money elsewhere through self-employment or freelance work, as long as that work is separate from your employer and doesn’t breach any contract clause about outside work.
Do I need to tell my employer if I’m freelancing during maternity leave?
You’re not legally required to unless your contract has a clause about outside employment or conflict of interest, but it’s worth checking that clause and sending a short email to HR if there’s any overlap with your employer’s business, so there’s no awkward surprise when you’re back.
How many hours can I work for my own business while on maternity leave?
There’s no legal limit on hours worked for your own separate business, unlike Keeping in Touch days for your employer, which are capped at 10. The practical limit is usually your own energy and childcare arrangements rather than any rule.
Do I have to pay tax on side hustle income earned during maternity leave?
If you earn over £1,000 in a tax year from self-employment, you need to register with HMRC and file a self-assessment return by 31 January the following year, and pay any tax owed by the same date. Below £1,000, the trading allowance means you don’t need to declare it.
