More than four in 10, or 41%, of US professionals volunteer outside of work, according to a survey released today by Robert Half International Inc. (NYSE: RHI).

Most respondents said their philanthropic activities help them improve their sense of well-being and effectiveness at the office.

“Volunteering can help employees at any level build their careers,” said Paul McDonald, senior executive director for Robert Half. “Not only does it provide the gratification of giving back to the community, but it could open doors to a new professional opportunity or business connection.”

Respondents who reported they volunteer outside of the office were asked, “How does volunteering outside of work help you professionally?” Multiple responses were permitted. Their responses:

• Enhances my wellness (e.g., greater work-life balance) so I can be more effective at work: 61%
• Expands my network: 57%
• Helps me gain new skills: 49%
• Increases visibility for my company: 35%

The survey was developed by Robert Half and conducted by an independent research firm. It is based on responses from more than 1,000 workers ages 18 and over employed at US companies.