How Long To Leave A Tampon In Dear BeingGirl Experts, I just started my period today! I just started wearing a tampon! I need to know how long I can wear it. The box says 6 –9 grams. I need to know if I can wear it a whole day at school (from 7:00 a.m. to 3:00 p.m.). How much is 6 –9 grams, and can I wear it a whole school day? Ashley --- Dear Ashley, Congratulations! Tampons come in varying absorbencies appropriate for your different flow days. "6–9 grams" is a measure of how much fluid the tampon can hold, and how long it takes to saturate the tampon depends on your flow rate. You should be using the lowest absorbency tampon for your flow and changing the tampon every 4–8 hours. If you find your tampon fully saturated before 4 hours, this is an indication you need to be using the next absorbency size. If you remove the tampon at 8 hours and still see white fiber on the tampon, your tampon is too absorbent. Drop down one absorbency the next time. It takes experimenting to know what absorbency of tampon you need for any day of your period. Use a pantiliner when you are learning to use tampons, so that you do not have any staining. If you have a heavier flow than the tampon holds, you'll know when you have to change. Hope this is helpful, Your BeingGirl Experts Wondering how long to leave a tampon in? Get answers from the experts at BeingGirl.com.