21st Night is more than the best flashcard app you’ve ever seen.

If you’re a test-taker, 21st Night organizes your studying. It’ll let you know when you need to review problems and concepts before you forget them.

If you’re a tutor, 21st Night helps you analyze what your students are struggling with and make sure you’re helping where you’re needed.

It works for both self-studiers and educators, creating a better learning experience for everyone. Interested in how it works? Read on!

Try 21st Night free for 14 days.

The main 21st Night page, showing cards, review dates, etc.
The main 21st Night page. From here, you can see the cards you have to review, study your deck, or examine your proficiency on the cards that you’ve done.

How 21st Night has helped my students

I run a test-prep business in Boston, MA called Trevor Klee, Tutor. We do only graduate exams: GMAT, GRE, LSAT, and MCAT.

These are hard exams. Really hard. Each one of them takes a minimum of 100 hours of studying, and the MCAT usually takes more like 300 hours. 300 hours of studying is like 20 hours/week of studying for 3.5 months.

Our clients rely on us to be their guides through these exams. They want us to figure out what they’re missing, teach them the necessary material, and make sure that they have everything at their fingertips for test day.

21st Night is a crucial part of how we guide our clients. We make sure our clients remember what we teach with the spaced repetition algorithm. We use the analytics function of 21st Night to see what our clients are struggling with, and we use the sharing function to send them additional material.

21st Night, in short, serves as a map and as a lantern, letting us and our clients see what to work on next and what pitfalls to avoid.

Try 21st Night free for 14 days.

Everything you can do with 21st Night

There are a lot of things you can do with 21st Night.

Obviously, you can put any sort of topic into 21st Night. Whether you’re working with math, French, or SAT, 21st Night works for you.

And our spaced repetition algorithm means that you (or your student) will be reminded of the things learned just as they’re about to be forgotten. On test day, the material learned in week 1 will be just as fresh as the material learned on week 6.

But 21st Night also lets you:

See detailed analytics on studying progress. Which topics do you (or your students) get wrong? When do you get them wrong? How often do your students study? These are questions that 21st Night can answer for you.

Collaborate on decks with friends and tutors. You never have to work alone! Get your friends to work with you, creating really good explanations to make your life easier. Or, share your deck with a tutor, so they can see how you’re doing and help you learn what you need to do next.

See your proficiency on questions, as well as when you need to study them next. Wondering how you’re doing? It’s right there! Wondering when you should review a card next? 21st Night will tell you!

Create and share a to-do list for your studying. Don’t waste time with a bunch of random notes scattered in random notebooks. It’s all right there.

Combine decks. Let’s say you’re studying biology, and you’ve created a deck for each exam throughout the year. Now it’s your final exam, so you need to study all of them. With 21st Night, you can create a new deck made up of your old ones. Easy as pie.

Try 21st Night free for 14 days.

Real results

“Your method of preparing for the GRE has been by far the best method I have encountered to succeed in this exam. If I were to take any other standardized examinations in the future, 21st Night would be the first tool I reached out for.”

Anirudh Sriram, University of Chicago Graduate Program in Computer Science

I increased from 590 to 680 in just 7 weeks, thanks to 21st Night and you!

Ink Eze, AsoEbiBella

Think these testimonials are impressive? We’ve got a lot more.

Who should use 21st Night?

Tutors who want to target exactly what their clients need to learn without wasting time on notes. Through our collaboration features, tutors can use 21st Night to see their clients’ progress on the problems they assign. Tutors can assign questions, write explanations, and then see how their clients are performing on the questions assigned.

This makes a big difference. Before, tutors had to spend time taking notes on each client in order to provide a personalized experience. This can add 30-60 minutes of work after each session, plus the time at the beginning of the session to analyze how a client is doing on the homework.

Tutors can save time and tutor in a more personalized way with 21st Night. More personalized means happier clients, which means more referrals and more revenue. What’s not to love?

Students who are struggling to progress on a subject or exams. Studying can be overwhelming. It’s difficult enough to keep track of everything you need to know. Then, you’re asked to apply literally all the knowledge you learned on some random question as the clock is ticking down. It’s nerve-wracking!

21st Night presents a better solution. Once you put your questions into 21st Night, it’ll help you learn those questions deeply. Then, it’ll help you remember everything, so it’s as fresh in your mind 6 months later as the day you learned it. When you take the exam, you’ll be ready.


Try 21st Night out for free for 14 days!

What makes 21st Night so effective?

Most students study for exams by doing question after question. By the time they get to the exam, they’ve done a lot of questions, but they haven’t learned from them.

21st Night works off of a mastery system. It forces students to learn from the questions they found tricky, mastering the concepts they’re weak on. Then, it schedules a review of the question to a later date, so that the concept can pass from short-term memory, to medium-term, to long-term.

As a result, by the time the student takes the exam, they remember the tricks and techniques that every question taught them. It’s all fresh in their mind, just as if they did those questions the day before.

Furthermore, 21st Night gives students analytics on which questions (and which sorts of questions) they’ve been struggling with. It lets them know their proficiency on those questions and categories. With 21st Night’s detailed analytics, students know what sort of questions they need to do next in order to get their goal score.

Try 21st Night out for free for 14 days!