Stämpelskatt only applies if you are buying real property
A private buyer of a house pays 1.5% in stämpelskatt, charged on the price or the assessed taxeringsvärde, whichever is higher, plus a fixed 825 kronor application fee to Lantmäteriet. A buyer of a bostadsrätt pays nothing at all, because a bostadsrätt is a share in a housing co-operative rather than real property and no title changes hands.
Since most Swedish flats are owned as bostadsrätter, that distinction decides whether the transfer-tax line on this page applies to you. The calculator models the house case. If you are buying a bostadsrätt, read the transfer tax as zero and the monthly avgift to the association as the building charge: it usually covers heating, water and the association's own loans, which is why it is far larger than a service charge elsewhere.
There is a second stamp duty most buyers meet: 2% on newly issued mortgage deeds, pantbrev. It applies only to deeds that do not already exist on the property, so on an older house with sufficient pantbrev in place it can be nothing, and it is not included in the buying costs here.
No mortgage insurance, but an amortisation requirement
Sweden has no mortgage insurance. Lending is constrained instead by an 85% loan-to-value cap and Finansinspektionen's statutory amortisation requirement, which forces a minimum yearly repayment of principal above certain loan-to-value and loan-to-income thresholds. The requirement means a Swedish mortgage cannot be run as an interest-only loan indefinitely, so the amortising schedule shown here is the realistic case.
Fastighetsavgift, the municipal property fee, is capped at a fixed maximum per dwelling each year, so it behaves as a flat annual charge rather than a rate on value, which is why an expensive house in Stockholm pays the same as a modest one.