What this calculator does
Give states to two made-up candidates and see who reaches the 270 electoral votes needed to win. The President of the United States is chosen by 538 electors, not directly by the national popular vote. Each state gets one elector for each member of Congress it has: its House seats plus its two senators. The District of Columbia gets 3. A candidate needs a majority of the electors, 270, to win.
Click or tap states on the tile map, or type postal codes into the two lists. The calculator shows each candidate's total and the votes still undecided. It also shows how many of those each candidate still needs. Maine and Nebraska can be split by congressional district, as their laws allow. The vote counts are the ones in force for the 2024 and 2028 elections, based on the 2020 census. The calculator makes no predictions. Its starting example is made up and isn't a real election.
Where it's used
Why this math matters outside the classroom:
- Civics class tallies. Students give a mock map of states to two candidates and add the votes, such as 54 + 40 + 30 = 124 for the three largest states.
- Reading the threshold. A class checks why 270 is a majority: half of 538 is 269, so one more than half is 270.
- Gap to the target. A student with 121 votes assigned works out 270 − 121 = 149 still needed, then compares it with the undecided votes.
- Census and seats. Students see that a state's electoral votes are its House seats plus two, so 38 seats give Texas 40 votes.
- Split states. A lesson on Maine shows its 4 votes as 2 at-large plus 1 for each of its 2 districts, so a 3–1 split is possible.
Grade level and standards: Grades 3–4; Common Core State Standards for Mathematics 3.NBT.A.2, 3.OA.D.8, 4.NBT.B.4. © Copyright 2010. National Governors Association Center for Best Practices and Council of Chief State School Officers. All rights reserved.
How to use it
- If you like, name the two candidates. Otherwise they're called Candidate A and Candidate B.
- Click a state on the tile map to switch it from undecided to candidate A, to candidate B, and back. Or type postal codes into each list, separated by commas.
- For Maine or Nebraska, open the district chooser on the map. Or type ME-AL, ME-1, ME-2 or NE-AL, NE-1, NE-2, NE-3. This assigns the at-large (statewide) votes and each district separately.
- Read each total, the undecided votes, and how many more each candidate needs. The table lists every state and who it's assigned to.
What the inputs mean
- Candidate A's name
- Only used to label the results. Leave blank for Candidate A.
- Candidate B's name
- Leave blank to use "Candidate B".
- States assigned to candidate A
- Two-letter postal codes such as CA, TX or DC, separated by commas, semicolons or new lines. Full state names work too, if you separate them with commas. A state code on its own means the whole state.
- States assigned to candidate B
- Any state in neither list counts as undecided. A state can't be in both lists. Maine or Nebraska can't be given both as a whole state and by its parts.
Formula and method
Candidate total = sum of the electoral votes of the states (and districts) assigned to that candidate Undecided = 538 − total A − total B Votes still needed = 270 − candidate total (0 once at 270 or more) State electoral votes = House seats + 2 senators; DC = 3
Winning takes a majority of all 538 electors. Half of 538 is 269, so a majority is 270. The two totals and the undecided votes always add up to 538. That means at most one candidate can reach 270.
Each state's count comes from the census, the national population count every ten years. After each census, the 435 House seats are divided among the states by population. Then two votes are added for each state's senators. The 23rd Amendment gives the District of Columbia as many electors as the state with the fewest people, which is 3.
Maine and Nebraska give two votes to the statewide winner (the at-large votes). They give one vote to the winner of each congressional district. Maine has 2 districts and Nebraska has 3, so their 4 and 5 votes can be divided. Every other state and DC gives all of its votes to one candidate.
Worked example
Candidate A is given AZ, CO, IL, KY, ME-1, MN, NC, OR, PA, UT and VA. Candidate B is given AL, GA, IN, MA, ME-AL, NE, NJ, NY, TX and WA. Everything else is undecided.
- A: 11 + 10 + 19 + 8 + 1 + 10 + 16 + 8 + 19 + 6 + 13 = 121.
- B: 9 + 16 + 11 + 11 + 2 + 5 + 14 + 28 + 40 + 12 = 148.
- Undecided: 538 − 121 − 148 = 269.
- A still needs 270 − 121 = 149, and B still needs 270 − 148 = 122. Both must come from the 269 undecided votes.
Result: No one has 270 yet: Candidate A has 121 and Candidate B 148, with 269 votes undecided. Maine's district 2 is among the undecided votes.
Understanding the result
The 'still needs' figure is the gap to 270. Compare it with the undecided votes. If a candidate needs more votes than are undecided, that candidate can no longer reach 270.
A 269–269 tie is possible because 538 is an even number. It's the only way to assign every vote without anyone reaching 270.
The totals count electors, not votes cast by the public. A candidate can reach 270 while getting fewer popular votes nationwide.
Assumptions and limitations
- Electoral votes follow the 2020-census allocation used for the 2024 and 2028 elections.
- Every elector votes for the candidate they were assigned to. Faithless electors (see the FAQ below) aren't modelled.
- Only two candidates are tracked. Votes for any third candidate would sit in the undecided total.
- This is a counting tool. It doesn't predict or project any election, and it uses no polling or results data.
- The allocation will change after the 2030 census. The counts here apply through the 2028 election.
- If three or more candidates win electors and no one has a majority, the House would choose among the top three. This calculator doesn't model that.
Frequently asked questions
Why is 270 the number needed to win?
There are 538 electors: 435 for the House seats, 100 for the senators and 3 for DC. A candidate needs a majority of them, which means more than half. Half of 538 is 269, so the smallest majority is 270.
What happens in a 269–269 tie?
Under the 12th Amendment, the House of Representatives chooses the President in what's called a contingent election. Each state's group of representatives casts a single vote. A candidate needs a majority of the states, 26 of 50. The Senate separately chooses the Vice President. Each senator votes, and a majority of the whole Senate, 51, is needed. The same process applies whenever no candidate has a majority of electors.
What is the difference between winner-take-all and the district method?
Forty-eight states and DC give all of their electors to whoever wins the state's popular vote. Maine and Nebraska give two electors to the statewide winner and one to the winner of each congressional district. So their votes can be divided between candidates, as in the example above.
What are faithless electors?
A faithless elector is one who votes for someone other than the candidate they promised to support. They have been rare and have never changed an outcome. Many states now bind their electors by law. In 2020, the Supreme Court ruled that states may enforce those promises.
Can I type state names instead of codes?
Yes. Full names such as New York or South Carolina work when you separate entries with commas. Codes work in capital or small letters. DC, D.C. and District of Columbia all mean the District. If an entry isn't recognized, the error message names it so you can fix it.
Sources
- U.S. Census Bureau: 2020 Census Apportionment Results, Table 1 (checked 2026-10-19)
- National Archives: The Constitution, Amendments 11–27 (12th and 23rd Amendments) (checked 2026-10-19)
How this calculator is checked
Method: Electoral votes per state = 2020-census House apportionment (U.S. Census Bureau Table 1) + 2 senators; DC = 3 under the 23rd Amendment; majority = 270 of 538; contingent election per the 12th Amendment. Every state's count is re-derived from the census table in the tests. The calculation is covered by automated tests with known reference values and edge cases. Last updated 2026-10-18. Found a problem? Tell us.
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