Voters Aged 18-29 Up 74% In Primary

(Source: MIRS.news, Published 09/09/2026) Michigan's August primary electorate may be getting steadily grayer, but 2026 brought a noticeable exception: Voters under 40 showed up in their largest share in nearly three decades.

An analysis of Michigan's Qualified Voter File (QVF) by Practical Political Data's Mark Grebner found voters ages 18 to 39 made up 17.15% of those who participated in last month's primary, up from 13.13% in 2024 and 14.55% in 2022.

Also, in trying to piece together why Michigan's primary turnout was a record 2.6 million voters, Grebner discovered another trend. Low propensity voters — those unlikely to participate in a primary election — showed up in considerably larger numbers across the board.

"Somebody actually got these relatively low-voting groups to the polls," Grebner told MIRS.

It starts with voters between 18 and 29. Only 5.73% of those voting in the 2024 primary election were those 29 and younger. In 2026, that percentage was 7.86%, a notch lower than the 7.88% from 2020, but considering the higher voter totals in general, the 2026 turnout numbers were the state's highest among young people in at least the 28 years recorded.

Voters ages 30 to 39 made up another 9.29% of this year's electorate, compared to 7.4% in 2024. That's their highest share since 2002.

"Michigan's getting older, but in last month's elections there was a noticeable uptick in voting by people under 40 or so," Grebner said.

Using Grebner's estimates, about 439,000 voters under 40 participated this year, compared with about 265,000 in 2024 — roughly 174,000 more voters, or an increase of about 66%.

The estimated number of 18- to 29-year-old voters jumped from roughly 116,000 in 2024 to 201,000 this year. Among 30- to 39-year-olds, the estimated count rose from about 149,000 to 238,000.

Grebner cautioned that the numbers aren't designed to precisely duplicate the state's official turnout totals. The calculations are based on snapshots of the QVF taken at different times, and changes to the voter file — particularly the deaths of older voters — can affect the numbers.

He also attempted to calculate the latest four elections using the same methodology he used for his earlier analysis, but cautioned there could be subtle differences.

Still, Grebner said, "the general trend is clear."

That trend has been toward a considerably older primary electorate.

In 1998, voters age 60 and older accounted for 43.06% of primary voters. They crossed 50% in 2006 and peaked at 63.09% in 2024.

This year, the 60-and-older share retreated to 58.35%.

That doesn't mean fewer senior citizens voted. With overall turnout higher, Grebner's numbers suggest roughly 1.49 million voters age 60 and older participated this year, compared with about 1.27 million in 2024.

Instead, younger voters simply grew faster as a share of the expanded electorate.

The long-term demographic squeeze has been felt most strongly among middle-aged voters. In 1998, those ages 40 to 59 represented nearly 38% of the primary electorate. This year, they represented slightly more than 24%.

"As we all age, 60+ voters are becoming an increasing majority, mainly at the expense of the groups in the 40–60 range," Grebner said.

The age findings also provide another possible clue to something Grebner noticed when examining why he badly underestimated overall turnout this year.

Before the primary, Grebner had been expecting roughly 2.2 million to 2.3 million voters. His post-election analysis counted nearly 2.6 million.

When he examined where his projections went wrong, Grebner found that the biggest surprise on the Democratic side came from voters who historically rarely participate in primaries.

Among one group of low-propensity Democrats, Grebner estimated they had a 5% chance of voting; actual turnout was about 11%. In another low-propensity band, he expected about 80,000 voters and instead saw roughly 200,000.

Republicans also exceeded Grebner's expectations, but the additional GOP turnout was concentrated more among voters with middling histories of participating — those Grebner estimated had roughly a 30% to 70% chance of voting.

Grebner said he isn't yet prepared to say what caused the Democratic surge. He floated everything from individual campaigns to President Donald Trump and the broader political atmosphere.

"Mostly, among Democrats, it was low propensity voters," he said. "And among Republicans, it was mid-propensity voters."

Before completing the age analysis, Grebner suspected those unexpected voters would skew younger. The new figures support that possibility, although the age data by itself doesn't establish whether those younger voters were Democrats, Republicans or how frequently they had voted in prior elections.

Another piece may be absentee voting.

Michigan entered the Aug. 4 primary with more than 1 million absentee ballots already returned, 21.5% more than at the same point before the 2022 primary. More than 1.9 million voters had requested mail ballots, many through the state's permanent mail ballot list.

Grebner said he wants to examine whether automatically mailing ballots to voters on that list increased participation among people who ordinarily would not have taken the initiative to request a ballot for a primary.

For now, though, the age numbers establish one thing: after years in which Michigan's primary electorate became progressively older, 2026 brought younger voters back into the mix in numbers not seen for years.