MUMBAI, January 16 (Reuters) - India's oil-to-telecoms conglomerate Reliance Industries Ltd beat analysts' estimates to post a 10 percent increase in third-quarter standalone net profit, as high margins from its core business of crude oil refining helped bolster earnings. The "standalone" profit and revenue figures include the company's refining and petrochemicals business and oil and gas exploration in India. Standalone net profit rose to 80.22 billion rupees ($1.18 billion) for the three months to Dec. 31 from 72.96 billion rupees reported a year earlier, Reliance, controlled by India's richest man Mukesh Ambani, said in a statement on Monday. Analysts on average had expected a standalone profit of 78.5 billion rupees, according to data compiled by Thomson Reuters. Its standalone revenues for the quarter came in at $9.8 billion, up 9 percent from a year ago due to higher margins from selling petrol and diesel. Refining and petrochemicals contribute around 90 percent to overall revenue and profit. The company said its gross refining margin, or profit earned on each barrel of crude processed - a key profitability gauge for a refiner - was $10.8 per barrel for the quarter. On a consolidated basis, which includes its telecom, retail and U.S. shale gas operations, its net profit came in at 75.67 billion rupees. Reliance commercially launched its fourth-generation (4G) telecoms network, Reliance Jio, on Sept. 1 offering free voice and data service to its subscribers until the end of March. The telecoms venture, in which the company has invested approximately $20 billion, had built a subscriber base of 72.4 million by Dec. 31, Reliance said. Reliance's flagship refining operations, with a 1.2 million barrels per day crude oil refinery in the western state of Gujarat, reported a 4.3 percent fall in profitability for the December quarter to $912 million. The petrochemicals business saw a 25.5 percent jump in profit to $486 million, Reliance said.