National apportionment of MP seats in the Riksdag
The electoral system in Sweden is proportional. Of the 349 seats in the national diet, the unicameral Riksdag, 310 are fixed constituency seats allocated to constituencies in relation to the number of people entitled to vote in each constituency. The remaining 39 leveling seats are used to correct the deviations from proportional national distribution that may arise when allocating the fixed constituency seats. There is a constraint in the system that means that only a party that has received at least four per cent of the votes in the whole country participates in the distribution of seats. However, a party that has received at least twelve per cent of the votes in a constituency participates in the distribution of the fixed constituency seats in that constituency.
Apportionment of fixed constituency seats
| Constituency | 1970 | 1973 | 1976 | 1979 | 1982 | 1985 | 1988 | 1991 | 1994 | 1998 | 2002 | 2006 | 2010 | 2014 | 2018 |
| Stockholms kommun | 31 | 29 | 27 | 26 | 26 | 25 | 25 | 25 | 25 | 26 | 27 | 27 | 28 | 29 | 29 |
| Stockholms län | 24 | 27 | 28 | 29 | 30 | 31 | 32 | 32 | 33 | 34 | 35 | 36 | 37 | 38 | 39 |
| Uppsala län | 8 | 8 | 9 | 9 | 9 | 9 | 9 | 9 | 10 | 10 | 10 | 11 | 11 | 11 | 11 |
| Södermanlands län | 9 | 9 | 9 | 9 | 9 | 9 | 9 | 9 | 9 | 9 | 9 | 9 | 9 | 9 | 9 |
| Östergötlands län | 15 | 15 | 15 | 15 | 15 | 15 | 15 | 15 | 15 | 15 | 15 | 14 | 14 | 14 | 14 |
| Jönköpings län | 12 | 11 | 11 | 11 | 11 | 11 | 11 | 11 | 11 | 12 | 11 | 11 | 11 | 11 | 11 |
| Kronobergs län | 6 | 6 | 6 | 6 | 7 | 6 | 6 | 6 | 6 | 6 | 6 | 6 | 6 | 6 | 6 |
| Kalmar län | 10 | 9 | 9 | 9 | 9 | 9 | 9 | 9 | 9 | 9 | 8 | 8 | 8 | 8 | 8 |
| Gotlands län | 2 | 2 | 2 | 2 | 2 | 2 | 2 | 2 | 2 | 2 | 2 | 2 | 2 | 2 | 2 |
| Blekinge län | 6 | 6 | 6 | 6 | 6 | 6 | 6 | 6 | 6 | 6 | 5 | 5 | 5 | 5 | 5 |
| Kristianstads län | 10 | 10 | 10 | 11 | 11 | 11 | 11 | 11 | 11 | - | - | - | - | - | - |
| Fyrstadskretsen | 18 | 18 | 18 | 17 | 17 | 17 | 17 | 17 | - | - | - | - | - | - | - |
| Malmöhus län | 10 | 10 | 10 | 11 | 11 | 11 | 11 | 11 | - | - | - | - | - | - | - |
| Malmöhus läns norra | - | - | - | - | - | - | - | - | 9 | - | - | - | - | - | - |
| Malmöhus läns södra | - | - | - | - | - | - | - | - | 11 | - | - | - | - | - | - |
| Malmö kommun | - | - | - | - | - | - | - | - | 8 | 9 | 9 | 9 | 9 | 10 | 10 |
| Skåne läns västra | - | - | - | - | - | - | - | - | - | 9 | 9 | 9 | 9 | 9 | 9 |
| Skåne läns södra | - | - | - | - | - | - | - | - | - | 11 | 11 | 11 | 12 | 12 | 12 |
| Skåne läns norra och östra | - | - | - | - | - | - | - | - | - | 10 | 10 | 10 | 10 | 10 | 10 |
| Hallands län | 7 | 8 | 8 | 9 | 9 | 9 | 9 | 9 | 9 | 10 | 10 | 10 | 10 | 10 | 10 |
| Göteborgs kommun | 17 | 17 | 17 | 17 | 16 | 16 | 16 | 16 | 15 | 16 | 17 | 17 | 17 | 17 | 17 |
| Bohuslän | 10 | 10 | 10 | 10 | 10 | 11 | 11 | 11 | 11 | - | - | - | - | - | - |
| Älvsborgs läns norra | 9 | 9 | 9 | 9 | 9 | 9 | 9 | 9 | 9 | - | - | - | - | - | - |
| Älvsborgs läns södra | 7 | 7 | 7 | 7 | 7 | 7 | 6 | 7 | 6 | - | - | - | - | - | - |
| Skaraborgs län | 10 | 10 | 10 | 10 | 10 | 10 | 10 | 10 | 10 | - | - | - | - | - | - |
| Västra Götalands läns västra | - | - | - | - | - | - | - | - | - | 11 | 11 | 11 | 12 | 12 | 11 |
| Västra Götalands läns norra | - | - | - | - | - | - | - | - | - | 9 | 9 | 9 | 9 | 9 | 8 |
| Västra Götalands läns södra | - | - | - | - | - | - | - | - | - | 6 | 6 | 6 | 6 | 6 | 7 |
| Västra Götalands läns östra | - | - | - | - | - | - | - | - | - | 9 | 9 | 9 | 9 | 9 | 9 |
| Värmlands län | 11 | 11 | 11 | 11 | 11 | 11 | 11 | 10 | 10 | 10 | 10 | 10 | 9 | 9 | 9 |
| Örebro län | 11 | 11 | 11 | 11 | 10 | 10 | 10 | 10 | 10 | 10 | 10 | 10 | 9 | 9 | 9 |
| Västmanlands län | 9 | 9 | 9 | 9 | 9 | 9 | 9 | 9 | 9 | 9 | 9 | 8 | 8 | 8 | 8 |
| Dalarnas län | 11 | 11 | 11 | 11 | 11 | 11 | 11 | 11 | 11 | 10 | 10 | 10 | 10 | 9 | 9 |
| Gävleborgs län | 12 | 12 | 12 | 11 | 11 | 11 | 11 | 11 | 11 | 10 | 10 | 10 | 10 | 9 | 9 |
| Västernorrlands län | 11 | 11 | 11 | 10 | 10 | 10 | 10 | 10 | 10 | 9 | 9 | 9 | 8 | 8 | 8 |
| Jämtlands län | 5 | 5 | 5 | 5 | 5 | 5 | 5 | 5 | 5 | 5 | 5 | 5 | 4 | 4 | 4 |
| Västerbottens län | 9 | 9 | 9 | 9 | 9 | 9 | 9 | 9 | 9 | 9 | 9 | 9 | 9 | 9 | 9 |
| Norrbottens län | 10 | 10 | 10 | 10 | 10 | 10 | 10 | 10 | 10 | 9 | 9 | 9 | 9 | 8 | 8 |
| Total fixed constituency seats | 310 | 310 | 310 | 310 | 310 | 310 | 310 | 310 | 310 | 310 | 310 | 310 | 310 | 310 | 310 |