SAN FRANCISCO — Google entered a new business beyond Internet search on Wednesday with a service within Gmail to make phone calls over the Web to landlines or cellphones.

The service will thrust Google into direct competition with Skype, the Internet telephone company, and with telecommunications providers. It could also make Google a more ubiquitous part of people’s social interactions by uniting the service for phone calls with e-mail, text messages and video chats.

“It’s one place where you can get in touch with the people that you care about, and how that happens from a network perspective is less important,” said Charles S. Golvin, a telecommunications analyst at Forrester Research.

Gmail has offered voice and video chat for two years, but both parties must be at their computers. Google said the new service would work well for people in a spot with poor cellphone reception or for those making a quick call from their desk.