MistakeBook

Q1: Who is MistakeBook for?

For students and self-learners who want to organize mistakes, review repeatedly, and prepare for exams (school tests, standardized exams, certifications, etc.).

Q2: Can I import questions from my Photos library?

Yes. You can also take photos with the camera, then crop and annotate while adding them.

Q3: How does Spaced Review calculate my next review time?

MistakeBook calculates the next interval using “Base interval × Familiarity multiplier”, and schedules the reminder at 21:00 on that day (you can change the reminder time in Settings).

Base intervals (based on the review count after you save this time)
[1, 2, 4, 7, 15, 30] (after the 6th review, the base interval stays at 30)

Familiarity multipliers
1 → 0.7 ｜ 2 → 1.0 ｜ 3 → 1.6 ｜ 4 → 2.4

Formula
Next days = round( Base interval[review count] × Familiarity multiplier )
Then set the time to 21:00 on that day (editable in Settings)

Examples (assume today is 2026-02-11)

Example 1: 1st review, familiarity 1
1 × 0.7 = 0.7 → round = 1 day
Next: 2026-02-12 21:00

Example 2: 2nd review, familiarity 3
2 × 1.6 = 3.2 → round = 3 days
Next: 2026-02-14 21:00

Example 3: 4th review, familiarity 4
7 × 2.4 = 16.8 → round = 17 days
Next: 2026-02-28 21:00

Example 4: 7th review, familiarity 2
From the 7th review onward, the base interval is fixed at 30
30 × 1.0 = 30 days
Next: 2026-03-13 21:00

Two special cases
• Familiarity 5: Mark as completed, remove it from the review list, and stop scheduling next reviews.
• Familiarity 0: Do not recalculate the next time (keep the existing schedule).

Q4: Will my data be uploaded to a server?

No. Your data is stored on your device.

Q5: How does the subscription work? What happens if I cancel?

MistakeBook offers two plans: Free and Subscription.
• Free: You can create up to 30 mistake entries.
• Subscription: Create unlimited mistake entries.

After you cancel:
Your existing mistake entries (including those beyond 30) will not be removed. You can still view and review them normally.
However, until you subscribe again, you won’t be able to add new entries (unless your total goes back to 30 or fewer, or you resubscribe).

Q6: How can I contact support?