The figures were aided by a one-off payment from outgoing sponsor PDVSA, the state-owned Venezuelan oil company, for early termination of an agreement.
That payment helped Williams, the only F1 team with a stock market listing, to increase revenues to £132 million in 2013 from £106m the previous year.
The group, which is developing an engineering business to commercialise its racing technology, reported an operating profit of £12m, a turnaround after having lost £5m in 2012.
The return to the black will fuel the sense of optimism at Williams, which has a new title sponsor in drinks company Martini and has shown better form on the track.
Team founder and principal Sir Frank Williams said: “We have started the 2014 Formula One season well and hope we can continue to improve our performance.”