About 21 days. Starts with red blood bleeding for about 9 days. Then she is in "standing heat" from about 9 -15 days. Then she is in after heat. No blood just swollen and (I guess ) smells good to the boys. You can have her fixed after she has finished her heat - about 25 days from now when things are "back to normal". Please do not breed her (if you think you might) until she has heated 3x or more. They heat every 6 months or so. Also, unfixed females liked to mark when in or around heat. My Pugs like to sneak in and pee on my bed or one of the kids beds.