The Finnish Tax Administration issued a statement on Monday urging people to ensure their tax information is up to date.
The advice follows the discovery that approximately 886,000 individuals are currently paying too little tax due to incorrect information on their tax cards.
The authority advises people to review their income threshold and, if necessary, request a new tax card. If the income surpasses the limit specified on the tax card, the income will be subject to a higher tax rate than the standard rate.
This could mean paying tax on this year's income at a much higher rate further down the line.
Taxpayers can check their details by visiting the administration's online platform, Omavero.fi, or by viewing the preliminary figures as stated on their 2023 tax card, which is also delivered by post.
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