WASHINGTON — For the first time, the Census Bureau is giving US households a chance to respond to government surveys over the Internet, part of a bid to save costs and boost sagging response rates in a digital age.

The new online option will supplement the traditional census mail-out operation. It is a major shift for the agency, which has relied almost exclusively on paper forms since 1970 but is now moving toward a more Internet-based system after spending a record $13 billion on the 2010 census.