A pupil revises from their own notes for their final exams at school, while a student faces their January exams with a term's worth of lecture slides and old exams. Studyflash and Retain Cards, the flashcard app at retain.cards, both turn a PDF or a photo of notes into flashcards you review by spaced repetition. This review of Retain Cards compares how far each takes that material.
Our verdict: Studyflash is the better choice for turning your own notes, lecture slides and old exams into every study tool you need, set your way. It makes cards in the types you pick, image occlusion from your diagrams included. When we tested both apps in September 2026, Retain chose the card types itself every time.
Both apps at a glance
| Studyflash | Retain | |
|---|---|---|
| Card types | You pick them, image occlusion from your diagrams included | Fixed each time you generate |
| Summaries | You set the depth, length and format | Little for you to set |
| Mock exam | Shaped on your old exam or set by you, with Premium | Short, and mostly set by Retain |
| Free tier | Cards with spaced repetition, quizzes and unlimited tutor chat, free with no time limit and no ads | Retain Free: 5 images or 50 PDF pages a month |
| Price | Free plan with no time limit; Premium's price shows in the app. See what each plan includes | Retain Ultra €83.90 a year |
| Platforms | Web app, plus mobile apps for iPhone, iPad and Android | Web app and apps for iPhone, iPad and Android |
| Best suited to | Anyone with their own notes and slides who wants to pick the card types | Students wanting a simple app that picks card types |
Prices and features checked on 16 September 2026; prices vary by country and store.
Studyflash lets you pick your card types, Retain picks them for you
Studyflash, like the Retain Cards app, lets you choose how thorough your cards are, but in Studyflash you also decide which of six kinds of card to make, from definitions to image occlusion. Image occlusion hides part of your own diagram for you to recall. In our test, Retain gave us no choice of card types and made no image occlusion from the diagram we uploaded.
Studyflash takes a PDF, a document, a photo of handwritten notes, pasted text or a lecture recorded live. It builds the deck to cover all of it, with the number of cards and the level of detail you set. Studyflash works in 27 languages.
If a deck misses the mark, you tell Max, Studyflash's AI tutor, what to change without losing your own cards. Your flashcards are then ready for spaced repetition or a full cram session. The mobile app lets you study them offline.
Studyflash writes each summary to the settings you choose
In Studyflash you pick an overview or an in-depth summary, then set its length and format before it is written. Whichever you choose, the summary is built to cover all your material, and it can include reflection questions if you want. With a whole course uploaded, Retain's summaries came with very few settings.
Quizzes follow the number of questions and the question types you choose. Each answer is explained from your own material. Max has read the course and makes a summary or a quiz when you ask.
Mock exams shaped on your own old exam, or a short test you have little say in
The closer a mock exam comes to your real exam, the more it tells you, so Studyflash builds yours from the whole course and matches it to the structure and question style of your old exam or example questions. It draws on eight question types, times the paper and grades it on your country's scale. Without an old exam, you set the number of questions, the time limit and the question types yourself. Given a whole course, Retain produced a short mock exam with few options to shape it.
You can take mock exams whenever you like, as often as you like. Studyflash's study plan takes the course topic by topic to mastery and offers a mock exam as its last step. The plan suggests an order for the topics, but you don't have to follow it.
Which app to choose for your exams
Retain suits students who want a simple, flashcard-first app that settles the card types for them.
- Your own notes or a term's worth of lecture slides: Studyflash turns them into cards in the types your material needs, diagrams included.
- Summaries you control: Studyflash lets you set their depth, length and format before it writes them.
- A mock exam that looks like the real one: Studyflash shapes it on an old exam you upload.
- Studying without paying: Studyflash's free plan keeps flashcards, quizzes and spaced repetition with no ads. Chat with Max, Studyflash's AI tutor, is unlimited on it.
How we tested
Maximilian S. from the Studyflash team tested both apps in September 2026, uploading four master's-level lecture presentations unchanged to each. The 130 slides are heavy on images and charts, formulas, definitions and worked examples, with many notes a student typed onto them. Retain ran on its Premium plan. We looked at how many cards came out, whether you can pick the card types and whether a diagram became cards with parts hidden. Then came the summaries, podcast and mock exam made from all four, uploaded as one course.
Common questions about Retain and Studyflash
If you learn from slides and notes you already have, yes: Studyflash made 258 cards and Retain 193 from four lecture presentations of 130 slides, uploaded to both apps in September 2026. Studyflash also leaves the card types to you.
Yes, in a limited form: Retain Free allows up to 5 images or 50 PDF pages each month. On Studyflash's free plan you get flashcards, quizzes and spaced repetition with a monthly allowance of AI generations and no ads, while Premium adds unlimited generations, the podcast and the mock exam.
With notes, slides or old exams of your own, no: in our test, Retain chose the card types itself on every run. Studyflash lets you pick from six card types, including image occlusion on your own diagrams.
Yes, Retain makes summaries and a podcast from your uploads. Studyflash makes both too, with summaries at the depth, length and format you set and a two-voice podcast on whichever deck or course you choose.
Yes, Retain makes a mock exam from your material. Studyflash matches yours to an old exam or example questions you upload, and without one you set the question count, time limit and question types.
Retain turns your uploads into cards, summaries and a mock exam, and makes most of the choices for you. Studyflash leaves those choices to you: the card types you get, how deep your summaries go and whether a mock exam copies the layout of an old exam you upload.