As the April 15 filing deadline looms, the Internal Revenue Service reminds taxpayers that after three years, any unclaimed 2021 tax year refunds go to the U.S. Treasury.

The Internal Revenue Service is warning millions of Americans they might miss out on $1 billion in refunds if they don't act fast. Roughly 1.1 million Americans still have unclaimed tax refunds for 2021 that will disappear after April 15.

The IRS said the average refund amount has increased by 7.5% this year, going from $3,213 in 2024 to $3,453 so far in 2025. The average direct deposit refund was also up by 7.1% from last year – at an average of $3,505. The IRS began accepting tax returns on January 27, 2025.