Depends. Most federal loan servicers have strict guidelines they have to follow. Additional payments go towards late fees first (if applicable), interest second, and then principal. It kind of stinks but you will still save, SAVE A LOT if you make additional payments! On the other hand, private student loans have a bit more leniency. You can send them a letter stating that you want all additional payments sent to the principal of your loan. If you haven't done this yet, shoot us an email at Support@changedapps.com and ask for our template to send to servicers. It's super easy to fill out and will save you even more!