How many registered voters were there in California and how many ballots were cast in the 2024 presidential election?

1. How many ballots were cast — the prevailing estimates and their provenance

The conservative, repeatedly cited estimate in the reporting is “a little over 16 million Californians voted in the 2024 election,” an estimate advanced by the Public Policy Institute of California (PPIC) and echoed in election-analyst coverage; other outlets and studies describe the raw decline in votes versus 2020 as between about 1 million and 1.7 million fewer ballots cast ^{[1] [2] [3]}. Supplemental reporting from CalMatters provides candidate vote totals — Kamala Harris receiving over 9.2 million and Donald Trump roughly 6 million — which together account for more than 15 million votes and fit with the broader “just over 16 million” ballots-cast estimate once third-party votes and overvotes/undervotes are included ^[6].

2. How many registered voters were on the rolls — what the sources say and what they don’t

The provided sources consistently describe growth in registration driven in part by automatic voter registration and note “about 550,000 more registered voters” in 2024 than in 2020, but the snippet set did not include a single, fully cited statewide registered-voter total from the Secretary of State’s official documents in the excerpts supplied ^{[1] [7] [5]}. The Secretary of State maintains county-by-county participation and registration PDFs, and those official pages are the authoritative place to find a certified statewide registered-voter count; the available summaries in these sources emphasize trends rather than quoting the specific statewide registration figure in the excerpts provided ^{[4] [5]}.

3. Why analysts report different numbers and how to reconcile them

Estimates differ because analysts use different baselines (registered voters vs. eligible voters vs. total ballots counted), time windows for the roll snapshot, and methods for counting ballots that include provisional, late-arriving, or disqualified submissions; PPIC frames its “little over 16 million” estimate as the most recent estimate at the time of its analysis, while other research (USC’s Center for Inclusive Democracy, Ballotpedia, media summaries) emphasize percentage-point drops in turnout and alternative calculations that yield somewhat different absolute drops from 2020 ^{[1] [3] [8]}. Official county-by-county participation statistics published by the California Secretary of State provide the final certified tallies; the reporting points readers to those files for the definitive certified numbers ^{[4] [5]}.

4. Turnout context — percentage rates and the political significance

Turnout-rate reporting in the sources places California’s 2024 eligible-voter turnout around the low 60s (Ballotpedia reports a 62.1% eligible-voter turnout) and notes a sharp fall from 2020’s unusually high participation, with analysts flagging declines of about 4.8 to 11.3 percentage points depending on the denominator used (eligible versus registered voters) — trends that help explain why total ballots cast fell even as registration rose ^{[8] [1] [3]}. Analysts and academic briefs emphasize that lower participation among younger voters and many voters of color drove much of the decline, which in turn contributed to a narrower Democratic margin in California in 2024 even as the state remained decisively for the Democratic nominee ^{[9] [3] [6]}.

5. Bottom line — what can be stated with confidence and what requires checking official rolls

Based on the reporting provided, the best-cited figure for ballots cast in California’s 2024 presidential election is “a little over 16 million” (PPIC), and multiple analyses describe total ballots cast as more than 1 million fewer than in 2020 ^{[1] [2]}. The exact certified statewide count of registered voters at the time of the election is maintained by the California Secretary of State’s registration reports and county participation PDFs; the excerpts supplied note registration increased by roughly 550,000 compared with 2020 but do not quote a single statewide certified registration total in the snippets provided, so consulting the Secretary of State’s official registration/participation PDFs is required for the precise registered-voter number ^{[1] [4] [7] [5]}.