How to Remind a Recommender
If you're applying for graduate school, a scholarship, or a big promotion, you've probably asked someone to write a recommendation letter for you between two weeks and four months before it's actually due. After all, it's only polite to give someone enough time to complete a thoughtful, well-considered letter before you need to send it off.
Unfortunately, you can't always be sure that the recommender is going to remember to write the letter in time for the deadline. So you might need to send a little reminder that's brief, polite, and professional.
Don't wait until the deadline. If you look up your application online and see that your recommender hasn't uploaded their letter yet, it's time to take action. But if it's only one day (or several hours, yikes!) before the deadline, then it's already too late. Make sure you give your recommender at least 3 - 4 days before the deadline in case they forgot and haven't even started yet.
Don't assume they've already done it. It can seem presumptuous (and even rude) to treat your recommender like they've forgotten to write your letter, so a reminder should just be a friendly note. Something along the lines of "I'm finishing my application and just wanted to remind you that the deadline for all materials is [date]." They'll be grateful for the reminder, especially if they're a busy person.
Offer to answer any questions. Finish your letter off with an offer for questions, or even express your sincere appreciation and the desire to bake them cookies or something so that the letter doesn't feel like it's entirely made up of reminders.
Index of letter of recommendation templates