Guides

#Start with your employment contract

Before you take your first assignment, read your employment contract and, if one exists, the collective agreement. Look for clauses on secondary employment, competing activity, and rules for work outside your normal hours. Employees also have a duty of loyalty to their employer, which among other things means you shouldn't compete with your employer or use their resources, customers or information in your own venture.

Be especially careful in three situations: if you have a non-compete clause, if your assignments are close to your employer's line of business, or if you're a public-sector employee, where special rules on secondary employment apply. In these cases, it's wise to check in advance.

The simplest, and usually best, approach is to raise the issue openly. Explain what you're planning to do, how much time it involves, and that it doesn't compete with your employer, then ask for written approval. It costs a short conversation and removes the unpleasant risk of being found out instead of having told them.

#Tax: why the back-tax bill can catch you off guard

This is where many people make a mistake that only shows up at tax return time. Only one payer is allowed to withhold tax according to the table for your main income. All other payers apply the Swedish Tax Agency's rules for secondary income, and that withholding isn't adjusted for your total income.

As a result, secondary income on top of a full-time salary is taxed at your marginal tax rate, which can be higher than the amount withheld. The difference becomes back tax. The more you freelance, the bigger that gap can get, and it arrives with a delay, after you've already spent the money.

Two countermeasures. Expect part of your secondary income to go to tax and set it aside as you go, rather than treating it as freely spendable. And apply for a tax adjustment (jämkning) with the Swedish Tax Agency once you know the withholding will be too low, so the correct tax is deducted at the source. How adjustment works and what levels apply is explained at skatteverket.se, which is also the right place to calculate your own situation.

#Time, energy, and your first assignments

The practical constraint is rarely legal — it's usually about time. So start small: a defined assignment with a clear deliverable beats an ongoing commitment you're not sure you can keep up with. Be upfront with the client about your availability instead of promising response times you can only meet during a good week.

Don't price yourself low just because the income is extra. A price that's too low is hard to raise later, and it also affects how the market values the type of work you do. Factor in the same costs a full-time freelancer would, including time that isn't billable.

#Two things to keep track of

If you receive unemployment benefits, one rule is absolute: always report all work, even small, short assignments. Failing to do so can lead to repayment claims. Contact your unemployment fund before taking an assignment and ask how it affects your benefits.

Also avoid registering a company before the volume justifies it. A registered business means tax filings and routines even during months without income, and that's rarely worth it for a few assignments a year. Being a light entrepreneur (egenanställd) lets you invoice without registering anything, and you can switch to your own company later if the work grows.

#Get started without setting up a company

With Truster you invoice without a company of your own: you get paid a salary with tax and fees already handled, avoiding both registration and ongoing business admin for work you do alongside your job. The platform is built by a payment institution authorised by the Finnish Financial Supervisory Authority and is used by more than 55,000 people across the Nordics. Truster is launching in Sweden by invitation: join the waitlist.