The short version: the best side hustle alongside your existing business is almost never a brand new idea, it’s a smaller, faster version of what you already do well, sold to a slightly different buyer. Pick something you can start with skills and assets you already own, test it for 30 days before you spend a penny building it, and be honest that it will eat hours you don’t currently have.
Why I even started thinking about a side hustle while running a business
In 2020 my speaking income fell by roughly 40% in about six weeks. Conferences cancelled, retainers paused, one client simply went quiet. I had a business, a decent reputation, and a diary that had suddenly gone white. What I didn’t have was a second income stream that didn’t depend on other people’s events happening.
So I started running paid 90 minute LinkedIn workshops for small groups of business owners, charging £150 a head, capped at ten people. First one made £900 in an afternoon, cost me nothing but time and a Zoom link. That side hustle didn’t stay small, it became a chunk of what I now teach and sell as part of my consulting work. That’s the pattern I’d point anyone to: the side hustle that works is rarely a hobby you’re passionate about, it’s a sharper cut of the thing you’re already good at.
The uncomfortable bit nobody tells you before you start
Every side hustle article promises extra income without mentioning the trade off. Here it is plainly: a side hustle takes hours from somewhere, and that somewhere is usually your main business, your evenings, or your sleep. There’s no version of this where you add £500 a month of income and it costs you nothing. Something gives.
The people who make side hustles work long term pick ideas that feed the main business rather than compete with it for attention. My workshops fed my consulting pipeline. A friend who runs a small accountancy firm started selling a £39 template pack for freelancers doing their own bookkeeping, that template pack now brings her three or four accountancy clients a month who upgrade once they realise they’d rather pay her than do it themselves. The side hustle wasn’t a distraction, it was a funnel.
Pick a side hustle that competes with your business for the same buyer and you’ll end up tired and confused about which thing you’re running. Pick one that sits one step below or one step beside your main offer and it strengthens both.
Side hustles built on the skills you already sell
Start here before you invent anything new. If you run a marketing agency, sell a scaled down version of your service to people who can’t yet afford the full agency price:
- A one off “audit and action plan” call, priced at £200 to £400, no ongoing commitment
- A done for you template, checklist, or swipe file built from work you’ve already done for clients dozens of times
- A short paid workshop or webinar teaching the one thing clients ask you about most
- Freelance overflow work for other agencies who need a specialist for a fixed number of hours a month
If you’re a bookkeeper, sell a course on reading your own numbers. If you’re a copywriter, sell a template pack of headlines and email subject lines. If you run a small AI consultancy, package a one hour “AI readiness” session for solo business owners who aren’t ready for full implementation coaching yet but want a clear next step. These are all things you could have priced and sold by next week, not something you need six months to build.
Side hustles built on the audience you already have
If you’ve got even a small email list or a following, that’s an asset most people never monetise, and it’s the fastest side hustle to start because you’re not building an audience from zero. A course, a template, a paid newsletter tier, or affiliate recommendations for tools you use in your business all work here.
The online course as a side hustle route works particularly well for business owners because you’re not starting from scratch on expertise, you’re repackaging knowledge you’d otherwise give away in client calls for free. A £97 course sold to 40 people a month is £3,880, and unlike client work, the fifth sale doesn’t cost you an extra hour.
If your list is thin, building it is worth the side hustle in itself before you sell anything. I’ve watched clients go from nothing to a workable email list using the same slow, unglamorous method: one useful post a day, a clear signup offer, and consistency for three months, and the platform underneath it matters more than people admit, which is why I point people toward comparing email marketing platform alternatives before they commit to one that gets expensive the moment their list grows. Same logic applies to social platforms, and if you’re starting an Instagram presence from zero for a side hustle, the practical steps in how to get your first 1000 Instagram followers are more useful than most generic advice because they don’t assume you’re starting with a following already.
Side hustles that pay, not pocket money
There’s a difference between a side hustle that earns £40 a month doing surveys and one that earns £2,000 a month doing something you’re skilled at. Business owners in particular don’t need the low value versions, you already have skills that are worth more than that. If you want a fuller list of ideas that pay meaningfully rather than trivially, I’ve laid out the specifics, including real numbers, in side hustle ideas that pay you real money, not pennies. The short version of that longer piece: consulting, coaching, done for you services, and digital products built from existing expertise consistently outearn content creation for its own sake, gig work, or reselling.
A concrete example of the gap: a freelance social media manager charging £35 an hour doing ad hoc posts for small local businesses will struggle to clear £600 a month working evenings. The same person running a £250 “social media audit and 90 day plan” for four clients a month makes £1,000 for roughly the same number of hours, because they’re selling judgement, not time.
Side hustles built on what you already own or have spare
Not every side hustle needs to be knowledge based. If you’ve got a spare room, a driveway, storage space, or equipment sitting idle, renting it out is passive in a way most “passive income” schemes aren’t. A parking space near a train station or football ground can bring in £80 to £150 a month with zero ongoing effort once it’s listed. This isn’t glamorous and it won’t build a personal brand, but it’s real money for close to no time input, which matters if your business already takes every spare hour you have.
If you want the fuller picture on what passive income requires before it becomes passive, because most of it takes six to twelve months of unpaid setup work first, I wrote about this honestly in how do I generate passive income, including what the first year really looks like rather than the version people sell you.
If you’re starting later, or starting small on purpose
Age and stage change what makes sense. Someone running a business at 55 with grown up children and equity in a house has different assets, and different risk tolerance, than someone at 30 juggling a mortgage and a toddler. If that’s you, the practical, unglamorous version of this conversation, including what works when you’re starting a side income later in life rather than at 25 with nothing to lose, is in side hustles for women over 50. Plenty of the advice in general side hustle content assumes you have unlimited evenings and no existing commitments, and that’s simply not true for most business owners past 40.
How to test an idea before you build anything
Here’s the step by step version I’d give a client sitting across from me, not a theoretical framework:
- Week 1: Write down the one thing people already ask you for advice on, unpaid, at least once a month. That’s your idea, not something new.
- Week 1, same day: Price it. Pick a number that feels slightly too high. If it’s a service, £150 to £300 for a single session is a sensible starting point for most consultants and specialists.
- Week 2: Offer it to five people directly, by name, by email or message, not a public post. Ask three of them if they’d pay for it before you build a single page or slide deck.
- Week 3: If one person pays, deliver it, badly if necessary, and take notes on what was hard, what took longer than expected, what they asked for that you hadn’t planned.
- Week 4: Decide, using actual numbers not vibes, whether £150 for four hours of prep and delivery is worth repeating. If it isn’t, you’ve lost a month, not a year.
This is deliberately smaller and slower than most “launch your side hustle” content suggests. Most of that content wants you to build a course, a brand, and a funnel before you’ve sold anything once. Sell the one thing to one person first. Everything else is procrastination dressed up as preparation.
What to avoid
Skip anything that requires a big upfront spend before a single sale, that’s how people end up with a garage full of stock or a course nobody bought. Skip anything that requires you to learn an entirely new skill from zero when you already have paid ones. And skip anything that’s really an MLM structure wearing a side hustle costume, if the pitch focuses more on recruiting other sellers than on selling an actual product to an actual customer, walk away regardless of the numbers they show you.
Also worth saying plainly: if your main business is struggling for time or cash right now, a side hustle is sometimes the wrong answer entirely, and fixing pricing, offers, or systems in the business you already have will outperform a new income stream you have to build from scratch. A side hustle should be additive, not a rescue plan for a business that needs different attention.
Frequently asked questions
How much time does a side hustle realistically take alongside a business?
Expect four to eight hours a week in the first three months if you want it to earn meaningful money, not pocket change. That drops once you’ve built templates, processes, and repeat clients, but the first quarter is the expensive one in time terms, so plan for it rather than being surprised by it.
Should my side hustle be related to my main business or completely different?
Related, in most cases. A side hustle that uses the same skills as your business but sells to a smaller or different budget of customer strengthens both, feeds leads back into your main offer, and doesn’t require you to learn a new skill set from zero. Completely unrelated side hustles work, but they take longer to become profitable because you’re starting from nothing twice.
What’s a side hustle idea I can start this week with no money?
Offer a one off paid consultation or audit in your area of expertise to five people you already know, priced between £100 and £250. No website, no branding, just a direct offer and a calendar link. This tests demand before you spend anything.
Is a side hustle worth it if my main business is already busy?
Only if it feeds the main business or fills a genuine income gap, not if it’s simply another project competing for the same attention. If your business is already stretched thin, fixing pricing or capacity in that business usually earns you more than a new side hustle would.
Related reading: How Do You Turn Playing Games Online Into A Small Income (I Tried It For A Week) and What Jigsaw Puzzle Games Online Are Worth Trying for a Mental Break.
