75 % sweeter than sugar: fructose is 42 percent sweeter to the human brain than granulated sugar, less is needed to achieve the same level of sweetness (wildernessfamilynaturals.com)
This sweetener provides the same level of sweetness as sugar in much smaller quantities. (foodinsight.org)
Either way, agave is a good substitute for sugar because, while it still has a fructose content, you need a lot less of it to achieve the same level of sweetness. (exsloth.com)