The primaries and caucuses before April 1 (above the gray bar) allocate their delegates proportionally (except Florida and Arizona). The ones after April 1 are allowed to use winner take all, although many of them don't
| State | Delegates | Date | Type | Romney | Gingrich | Santorum | Paul |
| Iowa | 28 | January 3 | Caucus | 25% | 13% | 25% | 21% |
| New Hampshire | 12 | January 10 | Primary | 39% | 9% | 9% | 23% |
| South Carolina | 25 | January 21 | Primary | 28% | 40% | 17% | 13% |
| Florida | 50 | January 31 | Primary | 48% | 32% | 13% | 7% |
| Nevada | 28 | February 4 | Caucus | 50% | 26% | 13% | 18% |
| Colorado | 36 | February 7 | Caucus | 35% | 13% | 40% | 12% |
| Minnesota | 40 | February 7 | Caucus | 17% | 11% | 45% | 27% |
| Missouri | 9 | February 7 | Beauty contest | 25% | - | 55% | 12% |
| Maine | 24 | February 11 | Caucus | 39% | 6% | 18% | 36% |
| Arizona | 29 | February 28 | Primary | 47% | 16% | 27% | 8% |
| Michigan | 30 | February 28 | Primary | 41% | 7% | 38% | 12% |
| Wyoming | 29 | March 1 | Caucus | 56% | 0% | 31% | 3% |
| Washington | 43 | March 3 | Caucus | 38% | 10% | 24% | 25% |
| Alaska | 27 | March 6 | Caucus | 32% | 14% | 29% | 24% |
| Georgia | 76 | March 6 | Primary | 26% | 47% | 20% | 7% |
| Idaho | 32 | March 6 | Caucus | 62% | 2% | 18% | 18% |
| Massachusetts | 41 | March 6 | Primary | 72% | 5% | 12% | 10% |
| North Dakota | 28 | March 6 | Caucus | 24% | 9% | 40% | 28% |
| Ohio | 66 | March 6 | Primary | 38% | 15% | 37% | 9% |
| Oklahoma | 43 | March 6 | Primary | 28% | 28% | 34% | 10% |
| Tennessee | 58 | March 6 | Primary | 28% | 24% | 37% | 9% |
| Vermont | 17 | March 6 | Primary | 40% | 8% | 24% | 26% |
| Virginia | 49 | March 6 | Primary | 60% | - | - | 40% |
| Kansas | 40 | March 10 | Caucus | 21% | 14% | 51% | 12% |
| Guam | 9 | March 10 | Caucus | Winner | |||
| Northern Marianas | 9 | March 10 | Caucus | Winner | |||
| Virgin Islands | 9 | March 10 | Caucus | Winner | |||
| Alabama | 50 | March 13 | Primary | 29% | 29% | 35% | 5% |
| American Samoa | 9 | March 13 | Caucus | Winner | |||
| Hawaii | 20 | March 13 | Caucus | 45% | 11% | 25% | 19% |
| Mississippi | 40 | March 13 | Primary | 30% | 31% | 33% | 4% |
| Puerto Rico | 23 | March 18 | Primary | 83% | 2% | 8% | 2% |
| Illinois | 69 | March 20 | Primary | 47% | 8% | 35% | 9% |
| Louisiana | 46 | March 24 | Primary | 27% | 16% | 49% | 2% |
| District of Columbia | 19 | April 3 | Primary | 70% | 11% | - | 12% |
| Maryland | 37 | April 3 | Primary | 49% | 11% | 29% | 10% |
| Wisconsin | 42 | April 3 | Primary | 43% | 6% | 38% | 12% |
| Connecticut | 28 | April 24 | Primary | 67% | 10% | 7% | 14% |
| Delaware | 17 | April 24 | Primary | 57% | 27% | 6% | 11% |
| New York | 95 | April 24 | Primary | 62% | 13% | 9% | 16% |
| Pennsylvania | 72 | April 24 | Primary | 58% | 11% | 18% | 13% |
| Rhode Island | 19 | April 24 | Primary | 63% | 6% | 6% | 24% |
| Indiana | 46 | May 8 | Primary | 64% | 7% | 14% | 15% |
| North Carolina | 55 | May 8 | Primary | 66% | 8% | 10% | 11% |
| West Virginia | 31 | May 8 | Primary | 70% | 6% | 12% | 11% |
| Nebraska | 35 | May 15 | Primary | 71% | 5% | 14% | 10% |
| Oregon | 28 | May 15 | Primary | 73% | 6% | 9% | 12% |
| Arkansas | 36 | May 22 | Primary | 68% | 5% | 13% | 13% |
| Kentucky | 45 | May 22 | Primary | 67% | 6% | 9% | 13% |
| Texas | 155 | May 29 | Primary | 69% | 5% | 8% | 12% |
| California | 172 | June 5 | Primary | 80% | 4% | 5% | 10% |
| Montana | 26 | June 5 | Primary | 69% | 4% | 9% | 14% |
| New Jersey | 50 | June 5 | Primary | 81% | 4% | 9% | 14% |
| New Mex%ico | 23 | June 5 | Primary | 73% | 6% | 11% | 10% |
| South Dakota | 28 | June 5 | Primary | 67% | 4% | 12% | 13% |
| Utah | 40 | June 26 | Primary | 93% | 0% | 2% | 5%; |