The poll of polls compiled for Swedish Radio News suggests the Social Democrats and Greens will get slightly more votes than the four centre-right Alliance parties.
But not enough to get their policies voted through parliament, even with tacit support from the Left Party.
The Left Party has previously said it will not offer passive support to a Social Democrat-led government, and wants posts in a red-green government.
While opposition leader Stefan Löfven is likely to become prime minister he will face a hard time, with the Alliance parties able to block raises in benefits or taxes if the Sweden Democrats also vote against.
The Sweden Democrats, often described as xenophobic, are not formally cooperating with any party, but have said they will vote against measures they see as costing too much money. Their party is polling just over 10 percent; almost double their vote in 2010, but still a disappointment for a party that sees itself as tapping into broad but hidden support.
The new Feminist Initiative party, which took a seat at the European parliament in May, is unlikely to get into Sweden's national parliament if the vet a vote similar to their current polling figure of 2.6 per cent.
Several recent polls have given differing results, underlining the uncertain nature of this election.
Key for the graphic:
S = Social Democrats
V = Left Party
MP = Green Party
M = Moderate Party
FP = Liberal Party
KD = Christian Democrats
C = Center Party
SD = Sweden Democrats
FI = Feminist Initative
Övr = Other parties