The census changes the Electoral College map because each state’s electoral votes equal its number of House seats plus its two senators, and House seats are handed out by population every ten years. States that grow faster than the country gain seats and electoral votes; slower-growing states lose them. The 2020 census set the map used in 2024 and again in 2028. The 2030 count will set the map for 2032.
How do House seats turn into electoral votes? #
Every state’s electoral votes = its House seats + 2. Washington, D.C. gets 3 under the 23rd Amendment. With 435 House members, 100 senators and D.C.’s 3, the total is 538, and a candidate needs 270, a majority, to win.
The two Senate-based votes never change. The House-based votes shift after every census, because the House has been fixed at 435 seats since the early 20th century and those seats have to be redistributed as the population moves. Our explainer on why the House is limited to 435 seats covers how that cap came about.
How does apportionment work? #
The Constitution requires an “actual Enumeration” every ten years (Article I, Section 2), and the Fourteenth Amendment says seats are apportioned by “the whole number of persons in each State.” That count includes every resident, citizen or not.
Congress uses the method of equal proportions (also called Huntington-Hill), in place since 1941:
- Every state gets one seat automatically. That’s 50 seats.
- For each possible next seat, the Census Bureau calculates a priority value: the state’s population divided by √(n × (n − 1)), where n is the seat number being assigned.
- The remaining 385 seats go, one at a time, to whichever state has the highest priority value at that moment.
Because seats go one at a time, the last few are decided by tiny margins. After 2020, New York lost its 27th seat to Minnesota by a hair: if New York had counted 89 more residents, or Minnesota 26 fewer, New York would have kept it.
The timeline from count to ballot #
- Census Day: April 1 of years ending in 0.
- Apportionment counts: due to the president by December 31 of that year. In 2020 the pandemic delayed delivery to April 26, 2021.
- Redistricting: states redraw congressional districts to match their new seat counts.
- First use: the next midterm (2022) and the next two presidential elections (2024 and 2028).
Who gained and lost electoral votes after 2020? #
Seven House seats moved among 13 states, according to the Census Bureau’s 2020 apportionment results.
| Gained | Electoral votes now | Lost | Electoral votes now |
|---|---|---|---|
| Texas (+2) | 40 | California (−1) | 54 |
| Florida (+1) | 30 | New York (−1) | 28 |
| North Carolina (+1) | 16 | Pennsylvania (−1) | 19 |
| Colorado (+1) | 10 | Illinois (−1) | 19 |
| Oregon (+1) | 8 | Ohio (−1) | 17 |
| Montana (+1) | 4 | Michigan (−1) | 15 |
| West Virginia (−1) | 4 |
It was California’s first seat loss in its history as a state. The overall pattern continued a long trend from the Northeast and Midwest toward the South and West.
How much difference does a new map make? #
It can be a few electoral votes in a close race. Run the 2020 presidential results on the post-2020 map and Joe Biden’s 306 electoral votes fall to 303, while Donald Trump’s 232 rise to 235, with no voter changing their mind.
Over decades the shifts add up. In the 1972 election, Pennsylvania, Ohio and Michigan together held 73 electoral votes. In 2024 and 2028 they hold 51. Texas and Florida together went from 43 in 1972 to 70 today.
For campaigns, this changes which paths to 270 are realistic. The Upper Midwest’s “Blue Wall” states are still pivotal, but each is worth less than it used to be, while Sun Belt states such as Georgia, North Carolina and Arizona carry more weight. Our look at the key swing states for 2028 covers which states are expected to decide it.
What could change after the 2030 census? #
Population estimates since 2020 show continued growth in the South and Mountain West, so most early projections expect Texas and Florida to gain again and several Northeastern, Midwestern and West Coast states to lose. Projections this far out can be several seats off, and they depend on migration and birth rates over the rest of the decade.
There’s also a live dispute about who gets counted. In 2026 there was a push to add a citizenship question to the 2030 census and to exclude immigrants without legal status from apportionment counts. Any such change would likely face court challenges, since the Fourteenth Amendment’s text refers to all persons. A 2020 attempt to exclude undocumented immigrants from apportionment was never carried out.
Whatever the 2030 count shows, the new map will first apply to the 2032 presidential election.
What stays the same #
- Minimum of three. Every state gets at least three electoral votes. Alaska, Delaware, North Dakota, South Dakota, Vermont and Wyoming have three, as does D.C.
- Winner-take-all in 48 states. Maine and Nebraska are the exceptions; see how Maine and Nebraska split their electoral votes.
- The Senate. Every state has two senators regardless of population.
Following the 2028 race before the map is tested #
The 2028 map is set, so the questions now are who runs and which states tighten. Election Tracker, our free iPhone app, has a 2028 Primary tab with polls for both parties’ fields, each with a 30-day average and trend line, and it tracks presidential approval with a 90-day chart. Every poll shows its pollster, sample size and dates. It doesn’t draw electoral maps; it’s for following the polling that shapes them.
Frequently asked questions #
How often does the Electoral College map change? #
Once a decade, after the census. The 2020 census set electoral votes for the 2024 and 2028 elections. The 2030 census will set them for 2032 and 2036.
Can a state lose electoral votes even if its population grows? #
Yes. Apportionment is relative. California and New York both grew between 2010 and 2020 but lost seats because other states grew faster.
Does the census count noncitizens for apportionment? #
Yes. The Fourteenth Amendment requires counting “the whole number of persons in each State,” and the census has always counted all residents for apportionment. Proposals to change that for 2030 are contested and would likely be decided in court.
What’s the minimum number of electoral votes a state can have? #
Three: two for its senators and one for its guaranteed House seat. Six states and D.C. currently have three.
Does the census affect the Senate? #
No. Every state has two senators regardless of population, so only the House, and therefore the House-based share of electoral votes, changes.