Basic tax-free allowance (”grundavdrag”) is a deduction that the Swedish Tax Agency approves automatically when calculating your tax.
If you did not live in Sweden for the whole of the income year, you only get a basic tax-free allowance for the part of the year that you lived here.
But if 90 per cent or more of your income from employment (including pension) for the income year concerned is declared in Sweden, you have the right to a basic tax-free allowance for the whole of the year even though you only lived here for part of the year.
You must request this yourself in your income tax return under point 17 “Additional information” (“Övriga upplysningar”).