Heartmath Institute has been doing research and developing reliable, scientifically validated tools on this topic for 33 years that help people reduce and avoid stress, and reach higher levels of potential while experiencing increased peace, satisfaction, and self-security. They have developed many excellent resources and tools, most of which are free.
They offer a Free, validated survey called, Personal Well-Being Survey, which measures 4 Dimensions: Stress Management, Adaptability, Resilience, and Emotional Vitality. Once filled out, it offers the results, report and strategies at no cost.