PenDrop vs KnowUp
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
PenDrop
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PenDropは、「アウトプット」 にこだわった、本気で英語を身につけたい人のためのトレーニングアプリです。 ただ英文法を「読む」、「穴埋め」、「並び替え」だけでは、英語力はつきません。 本アプリは、「一から英文を組み立てる(英作文ドリル)」 と 「記憶に定着させる(単語カード)」 という2つの強力なアウトプットサイクルを回すことで、実践的な英語力を確実に養います。 【PenDropの3つのコアメソッド】 「書く」から身につく!実践型・文法ドリル 選択問題ではありません。自分の頭で考え、ゼロから英文を組み立てるトレーニングです。 文法・構文ごとに体系化されたドリルで、曖昧な知識を「使える武器」に変えていきます。 間違えた箇所はその場でAIが徹底解説。なぜ間違えたのかを即座に理解できます。 脳科学に基づく「忘却曲線」単語学習 人間の記憶の仕組み(エビングハウスの忘却曲線)を利用し、忘れかけた瞬間に復習を促します。 覚えた単語は表示間隔が広がり、苦手な単語は重点的に出題。最短時間で最大の語彙力を構築します。 AIによる精密な添削コーチング あなたが書いた英語をAIが瞬時に分析。文法的な正誤だけでなく、より自然な表現への書き換えも提案します。 独学では気づけない「自分のクセ」や「ニュアンスのズレ」を修正し、洗練された英語へ導きます。 【こんな学習者に最適です】 インプット学習(読む・聞く)ばかりで伸び悩みを感じている方 瞬間的に英文を組み立てる「英語脳」を作りたい方 英検や入試のライティングで高得点を狙いたい方 ただの間違い直しアプリではありません。 PenDropで、圧倒的なアウトプット体験を始めましょう。
KnowUp
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Remember what you learn. KnowUp is an AI-powered flashcard app that helps you remember more with less effort. Using spaced repetition, it reminds you to review at the right time—before you're likely to forget. Whether you're learning vocabulary, preparing for exams, or studying for school, KnowUp helps you build knowledge that lasts. ■Review at the Right Time Forgetting is a natural part of learning. Research suggests that much of what we learn fades quickly without review. KnowUp uses the proven SM-2 spaced repetition algorithm to schedule reviews based on your learning performance. Reviewing at the right intervals helps strengthen long-term memory while reducing unnecessary repetition. ■Create Flashcards with AI Creating flashcards shouldn't take longer than studying. Simply take a photo of your textbook, class handout, or notes. AI automatically extracts questions and creates flashcards for you. Review the generated cards, make any edits you want, and start learning in minutes. ■ AI explains answers clearly Instead of just memorizing the answer, you can learn while understanding why it is correct. For example sentences and questions, AI provides easy-to-understand explanations of the content and expressions, helping you deepen understanding as you review. ■ Import Anki and Quizlet content in bulk You can continue using the flashcards and study content you already have. Import Anki and Quizlet content in bulk and use it directly for review in KnowUp. It reduces the need to recreate cards from scratch, so you can start studying right away. ■Stay Motivated Every Day Learning is easier when you can see your progress. • Earn XP every time you review • Level up as you continue learning • Build daily study streaks • Track your retention and study habits with detailed statistics ■Learn Together Studying with friends makes it easier to stay consistent. Invite a study buddy with a QR code or invitation code, share your learning progress, and encourage each other along the way. Perfect for: • Language learning • English vocabulary • School subjects • Certification exams • Memorization • Lifelong learning Study smarter. Remember longer. Download KnowUp and make every review count. https://www.apple.com/legal/internet-services/itunes/dev/stdeula/
Screenshots
Verdict
The clearest difference is in-app purchases: PenDrop at none against KnowUp's 2. KnowUp's advantage is update cadence (every 2 days vs every 5 days) and iOS requirement (15.0 vs 17.0). On price, ads and device support there is nothing between them.
Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS
Both are free to download. KnowUp sells 2 in-app purchases, starting at $2.99 per month. PenDrop asks for nothing beyond the download.
PenDrop ships an update every 5 days, KnowUp every 2 days. The most recent releases landed on October 12, 2026 and October 3, 2026 respectively.
| Parameter | PenDrop | KnowUp |
|---|---|---|
| Price | Free | Free |
| Update frequency | Every 5 days | Every 2 days — better |
| Ads | No | No |
| In-app purchases | No — better | Yes |
| Devices | iPhone, iPad | iPhone, iPad, iPod — better |
| Requires iOS | 17.0 | 15.0 — better |
| Further details — not scored | ||
| Size | 46 MB | 89 MB |
| Age rating | 4+ | 4+ |
| Developer | AKIO FURUTSUKA | Wenfeng Duan |
In-app purchases
PenDrop
No in-app purchases
KnowUp
- knowup monthly14 Days trial$2.991 Month
- knowup annual14 Days trial$24.991 Year









