(Reuters) - U.S. online restaurant reservation service provider OpenTable Inc reported quarterly results that beat analysts' estimates, helped by an increase in the number of seated diners.

Net income rose 7 percent to $7.5 million, or 32 cents per share, in the fourth quarter from a year earlier.

Excluding items, the company earned 46 cents per share, 3 cents above analysts' average estimates.

Revenue at the company, which helps users reserve tables at restaurants through its website and mobile apps, increased 16 percent to $43 million, slightly above the average analyst estimate of $42.5 million.

The revenue includes monthly subscription fees and a fee for each restaurant guest seated through online reservation. The company's revenue has now beaten analysts' estimates for three consecutive quarters.

Seated diners rose 22 percent to 32.8 million, while reservation revenue increased 21 percent to $24.5 million. Subscription revenue climbed 10 percent to $14.5 million.

The company said in November it plans to increase its focus on mobile devices and expects the integration of its app within Siri -- the voice-control personal assistant in Apple Inc's iPhone -- to help boost mobile reservations.

OpenTable expects first-quarter adjusted earnings in the range of 39 cents to 44 cents per share on revenue of $44.7 million to $46.1 million.

Analysts were expecting adjusted earnings of 46 cents per share on revenue of $45.8 million for the first quarter, according to Thomson Reuters I/B/E/S.

OpenTable's shares, which have risen about 25 percent in the last six months, were up 1 percent at $50.00 in extended trading. They closed at $49.31 on the Nasdaq on Thursday.

(The story corrects paragraph 6 to say that seated diners rose 22 percent to 32.8 million, not $32.8 million)

(Reporting by Chandni Doulatramani in Bangalore; Editing by Maju Samuel)