There's a key number to know before making a last-minute IRA contribution by April 15

As the April 15 tax deadline approaches, some investors will soon make a last-minute individual retirement account contribution.

Tax day is the deadline for 2025 IRA contributions, which typically brings a surge in deposits — and this season is no different, according to Fidelity Investments.

During the two weeks before March 20, average IRA contributions were up 18% compared to the previous five weeks, Fidelity data found. Nearly three-quarters of those deposits went to after-tax Roth IRAs vs. traditional pre-tax IRAs.

Whether you’re eyeing a Roth or traditional IRA contribution, it’s important to “know your numbers,” Rita Assaf, vice president of retirement offerings at Fidelity Investments, told CNBC.

For 2025, the IRA contribution limit is $7,000, with an extra $1,000 for investors age 50 and older, assuming the investor has at least this much income from working.