No fault divorce takes a minimum of 26 weeks (6 months).
Once the final order has been granted, there are additional aspects to take into consideration, including financial settlements and arrangements for children, if applicable. How long this will take to arrange will depend on the issues involved and on the level of cooperation given by your ex-spouse.
A good divorce lawyer will keep the momentum up and not allow the process to drag. They will also tell you about the likely timescale at the outset and as the case progresses.