The route without the leap
There are two ways to open a salon. The first is to resign, sign a lease and hope the diary fills before your savings run out. The second is to keep your job, work three evenings and a Saturday, and only give notice once the numbers say you should.
The second route is duller and much wiser. Your salary keeps arriving, your sick pay and pension accrual keep running, and you find out for real whether people will book with you and come back. That is the only question that matters in year one, and no business plan answers it.
What that second route takes in practice differs a lot by trade, and a nail studio or a massage practice sits very differently in it than a hair salon. A nail technician or massage therapist can start in a spare room at home or at the client's place with a treatment table and a set of tools. A hairdresser needs a wash unit and a chair, and fitting a wash unit at home in the evening hours alongside a job is not a project you fit in on the side. That is why most part-time hairdressers rent a chair in an existing salon instead of building their own.
The price is not financial. As a hairdresser you are running two things at once in a trade where you spend the day on your feet, inside an employment contract that has an opinion about it. This article is about those two things: what is allowed, and what fits.
If your plan is a clean exit rather than the middle step, read the separate article on moving from employment to your own salon instead.
Can your employer forbid it?
They can, but no longer just because they say so. Since 1 August 2022 a Dutch employer may only forbid side activities where there is an objective justification. A bare line in your contract saying side activities are not permitted is no longer enough on its own.
What can count as a ground: health and safety, the Working Hours Act, protecting confidential business information, and conflicts of interest. Those last two are what your plan runs into. You would be doing the same work in the same town, which is not a far-fetched conflict of interest, it is competition.
Source: kvk.nl on the ban on side activities, checked September 2026.
The practical conclusion is less cheerful than the law change suggests. The rule made boilerplate bans unusable, but an employer who explains that you are serving his clients in his catchment area has an argument that gets taken seriously. The justification also does not have to be in your contract in advance; it may be given at the moment the clause is invoked.
What to look up in your contract
Two clauses, and they are not interchangeable.
The nevenwerkzaamhedenbeding, the side-activities clause, is about working alongside your job in general. The rule above applies to it.
The concurrentiebeding, the non-compete, is about competing, and it is a heavier commitment. Article 7:653 of the Dutch Civil Code requires it to be agreed in writing with an employee of 18 or older on a contract for an indefinite period; on a fixed-term contract only with written reasoning of weighty business interests tailored to your role. Without that, the clause is probably invalid. The full conditions are set out in the article on moving from employment to your own salon; read that alongside this one if your contract has such a clause.
The distinction to notice here: a non-compete is usually written for the situation after your employment ends, but the wording almost never rules out that it also applies during it. Start part-time while you are still on the payroll and you breach the clause on the day you cut your first client. That is a different order of risk from an argument about side activities.
One variant sometimes removes the problem: start outside the radius named in the clause, in a different town. Travel time in exchange for peace of mind.
How many clients fit into three evenings and a Saturday
This is where most people go wrong, because they calculate with revenue per client instead of with chair time.
Take a 45-minute cut. Add settling up with the previous client, cleaning your tools and letting the next one in. Budget one hour per client, door to door.
Three evenings from 18:00 to 21:00 is 9 hours. A Saturday from 09:00 to 17:00 with a half-hour break is 7.5 hours. Together that is 16.5 hours of chair time a week, so 16 clients a week with a full diary.
Full diaries do not exist in year one. Assume 60 percent occupancy and you are at 10 clients a week. Take out holidays and public holidays and you keep 46 workable weeks: 460 clients in a year. At 45 EUR a treatment that is 20,700 EUR in revenue.
That figure matters for two reasons. It is real money next to a salary, and it sits just above the 20,000 EUR turnover threshold for the kleineondernemersregeling, so you have a VAT decision halfway through the year that is better taken in advance. There is a separate article on the KOR for salon starters.
Redo the sum with your own treatment times and prices. A two-hour colour appointment changes it, and not always against you.
The hours criterion: 1,225 hours, and the myth around it
To claim the zelfstandigenaftrek and the startersaftrek you have to meet the urencriterium: at least 1,225 hours a year spent on your business. It is all or nothing, and there is no partial deduction at 1,200 hours. The startersaftrek may be applied in at most 3 of your first 5 years, although from 2027 it is worth only 10 euro: the Belastingplan 2027 bill of 15 September 2026 cuts it from 2,123 to 10 euro and sets the zelfstandigenaftrek at 900 euro. Source: belastingdienst.nl and kvk.nl, checked September 2026.
If you start in 2027 that item is all but gone. The Belastingplan 2027 bill cuts the startersaftrek from 2,123 to 10 euro on 1 January 2027 and scraps it on 1 January 2028, and the zelfstandigenaftrek drops to 900 euro. Both chambers still have to pass the bill. Source: the Belastingplan 2027 bill on rijksoverheid.nl, 15 September 2026.
There is a second condition that gets quoted a lot and rarely correctly: you must spend more time on your business than on other work, employment included. If that always applied, this article would end here, because nobody with a 32-hour job clears it. But the Belastingdienst states explicitly that if you were not an entrepreneur in any of the 5 preceding years, only the first condition applies to you. As a starter, only the 1,225 hours count.
Will you make them? Do the sum. The 16.5 hours of chair time above, plus roughly 5 hours a week of admin, buying stock, photos and client messages, is 21.5 hours. Times 46 weeks is 989 hours. You are more than 200 hours short.
To reach 1,225 hours you need nearly 27 hours a week, 46 weeks a year, on top of a job. That is a fourth evening and part of your Sunday. It is possible, but call it what it is.
All hours for the business count, not only the ones with a client in the chair: bookkeeping, your price list, purchasing. Being available without working does not count, and reconstructing hours afterwards convinces nobody, so log them from day one.
Plan year one on the assumption that neither deduction applies to you. The euro amounts attached to them change from year to year; look them up on belastingdienst.nl rather than in a blog, this one included.
What you actually pay in tax on the side income
Four things to know in advance.
Entrepreneur or not. The Belastingdienst decides whether you have winst uit onderneming, business profit, or resultaat uit overige werkzaamheden, income from other activities. In the second category you pay tax on the result but get neither the entrepreneur deductions nor the mkb-winstvrijstelling. A few loose cuts a month is not a business; a salon with regulars, your own stock and your own risk is.
Your profit lands on top of your wage. This is the biggest surprise at the first assessment. Your employer already applies the payroll tax credit, so you do not get it again on your profit, and that profit is taxed at the rate that stacks on your salary. Ask for a voorlopige aanslag, a provisional assessment, once you have a realistic view of your profit, so you pay in instalments instead of in one go.
The mkb-winstvrijstelling. In 2026 it is 12.7 percent of your profit after reducing that profit by the entrepreneur deductions, and the Belastingplan 2027 bill keeps that percentage the same. No hours criterion is attached, so a part-timer keeps it. In 2026 the deduction is settled at a rate of 37.56 percent. Source: belastingdienst.nl, checked September 2026.
The Zvw contribution. On your profit you pay an income-related contribution of 4.85 percent in 2026, through a separate assessment. The maximum contribution income is 79,409 EUR, and your wage counts towards it. Source: belastingdienst.nl, checked September 2026.
One more point that only matters if things go wrong: if you later lose the job, UWV looks at the average number of hours per week you worked as a zzp'er in the 26 weeks before you became unemployed. Those are exempt hours and are not offset against your WW. Work more self-employed hours after that and the extra ones are offset. Source: uwv.nl, checked September 2026.
The tipping point
Part-time is an interim phase, not a destination. Three signals say the phase is over.
You are turning clients away. Not once, but as a pattern. Once you decline more than a handful of requests a month because your evenings are full, your job is costing you revenue instead of subsidising it.
Your clients cannot make the times you can. Three evenings and a Saturday exclude everyone who can only come on a weekday daytime. That is a large slice of the market, and they do not come back later to ask whether your hours have widened.
The sum works. Put your monthly profit after tax next to your net salary. At half, carrying on is a gamble. At three quarters with a full diary, running two jobs has become the more expensive option.
If you do jump, do it on the calendar rather than on feeling. Count backwards from your intended first full month: add your notice period, add the fact that notice runs to the end of the calendar month, and you have the date the letter goes in.
What to set up now
The practical problem with starting part-time is not tax, it is being reachable. You cannot pick up the phone while standing at your employer's chair, and a client who messages you on Tuesday afternoon and hears back on Wednesday evening has booked elsewhere in between.
So make booking possible without you: an address you can share, showing the evenings and Saturdays you actually have free, where someone can lock in a time at half past ten at night without waking you.
CelerBook gives you that address. You get your own booking page on your own subdomain with your treatments, your prices and only the hours you really have open. Confirmation emails go out automatically, an SMS reminder ahead of time costs 0.11 EUR excluding VAT per appointment, and every appointment writes itself through to your Google Calendar, so it sits next to your employed rota. The link runs one way: what you put in Google does not block your booking page, so you fence off your free evenings in your working hours. On your phone, the app shows you between two clients what has come in. The pricing suits a diary that is not full yet: the first 5 appointments each month are free, then 0.25 EUR excluding VAT per completed appointment, capped at 30 EUR a month for a solo operator plus 5 EUR per additional active staff member. No contract, and no usage means no cost. Try CelerBook for free.