Astra AI or Gizmo? They do different jobs. Pick Astra AI when you don't understand something: snap a maths, physics or chemistry problem and it explains the solution step by step, or talks you through it Socratic-style, and it can build exam prep and mock exams. Pick Gizmo when you understand the material but need to remember it: it turns your notes, PDFs, slides, YouTube videos and old Quizlet or Anki decks into flashcards and drills them with spaced repetition.
A disclosure first: we make Synt, a third option described near the end, so this is not a neutral review. We only state what we checked: prices and features come from the official US App Store listings, Astra AI's website and Gizmo's help center, checked on 8 November 2026.
The short answer
Astra AI (US App Store, 4.8 stars from about 5,600 ratings, 38 app languages) is an AI tutor. Its listing describes Snap and Solve, Solver and Socratic modes, lessons aligned with your country's curriculum across 14 subjects, and Exam Prep: a study plan from a photo of your exam or the topics you choose. Its website adds plans built from your notes, slides and past papers, realistic oral exams and timed mock exams.
Gizmo (US App Store, 4.8 stars from about 17,000 ratings, English only) is an AI flashcard app. "AI Import" converts Quizlet, Anki, YouTube, PDFs, notes and PowerPoint into flashcards, or scans handwritten notes; then you study with quizzes, spaced repetition, leaderboards and study games. It also lists an AI tutor and over a million free public flashcards.
Comparison table
| Astra AI | Gizmo | |
|---|---|---|
| Built around | Explaining problems and preparing exams | Flashcards and spaced repetition |
| Solve a problem from a photo | Yes, step by step (Snap and Solve) | Not listed |
| Tutor modes | Solver and Socratic | AI tutor listed |
| Turn your material into flashcards | Quizzes and lessons in Exam Prep | Yes: Quizlet, Anki, YouTube, PDF, notes, PowerPoint, scans |
| Exam plan and mock exams | Yes, plus oral exams (website) | Not listed |
| Spaced repetition and games | Not the focus | Spaced repetition, leaderboards, Hearts |
| App languages (App Store) | 38 | English only |
| Paid plan (US App Store) | Plus: $8 a week, $24 a month, $119.99 a year; Sigma $80 a month | Gizmo Unlimited: options from $6.99 to $154.99 |
Sources: the Astra AI and Gizmo US App Store listings (description and in-app purchases), astra-ai.co and Gizmo's help article on Hearts. Gizmo has no public pricing page, and the App Store doesn't say which period each Gizmo Unlimited price covers.
What each one costs
Astra AI says on its website that you can start free with no card, without listing the free limits. Astra AI Plus costs $8 a week, $24 a month or $119.99 a year in the US App Store, and its site says Plus unlocks unlimited tutoring, mock exams and podcasts. Sigma ($80 a month) is the heavy-use plan; there are also credit packs from $15 and an Exam Pass at $121.99.
Gizmo is free to download. The free version runs on Hearts: you start with 15, each wrong answer in Memorise mode costs one, and when they run out you wait 10 minutes before quizzing again. Gizmo Unlimited removes the wait; the US App Store lists it between $6.99 and $154.99, plus coin packs from $1.99.
Where Astra AI is better
Explanations. If you're stuck on an equation or a chemistry reaction, Astra shows the steps or asks you questions until you get there. Gizmo's listing is about flashcards.
Exam practice. Exam Prep builds a plan, and the website describes oral exams and timed mock exams with grading.
Languages and curriculum. 38 app languages and lessons aligned with your country's curriculum. Gizmo's app is English only.
Where Gizmo is better
Remembering. Spaced repetition decides which card comes back and when. For vocabulary, definitions, dates and formulas, that's what works.
Bringing your decks. Quizlet and Anki imports mean years of cards come with you.
Price to start. You can use Gizmo for free if you accept the Hearts wait; Astra's listed plans start at $8 a week.
A third option: Synt
This is ours. Synt sits between the two: it takes your notes (pasted text, a link or photos of your pages) and generates a summary, a 20-question quiz, flashcards and a concept map from that material, then plans sessions up to your exam date, re-asks the questions you got wrong (reworded) and puts a mock exam the day before.
On the web, the free plan covers pasted text, links and photos, including the study plan. PDF upload and YouTube are Pro, at €4.99 a week, €9.99 a month or €29.99 a year on synt.app's pricing page, with a 3-day trial; App Store prices are set per country.
Where Synt is weaker: no problem solver and no tutor chat (Astra wins for maths), no Quizlet or Anki import and no leaderboards (Gizmo wins there). Try the study planner or the flashcard maker.
How to choose
You don't understand the exercise: Astra AI, or a cheaper alternative.
You understand it but forget it: Gizmo.
You have notes, a test date and no plan: Synt.
Also compared: Knowunity vs Astra AI, Knowunity vs Gizmo and Gizmo vs Quizlet.
Astra AI vs Gizmo: FAQ
Is Astra AI better than Gizmo?
For explaining maths and science problems and preparing exams, yes. For memorising with flashcards and spaced repetition, Gizmo is the better tool. Many students would use one for each.
Is Astra AI free?
Astra AI's website says you can start free with no card required, but doesn't list the limits. Astra AI Plus costs $8 a week, $24 a month or $119.99 a year in the US App Store (checked 8 November 2026).
Is Gizmo free?
Gizmo is free to download, with free public flashcards. The free version uses Hearts (15 to start, one lost per wrong answer, a 10-minute wait when they run out). Gizmo Unlimited removes the limit.
Does Gizmo solve homework from a photo?
Gizmo's listing describes scanning pictures and handwritten notes to make flashcards, and an AI tutor, but not photo homework solving. For that, Astra AI, Photomath or Gauth are built for it.
