Best apps like calculator is

Tsugi - Japanese Vocab Mining

Smart n+1 Sentence Flashcards

Free

This app uses AI to analyze Japanese text and create personalized flashcards for vocabulary and grammar. It features spaced repetition, native audio, and progress tracking for intermediate to advanced learners.

SPI言語・非言語 対策問題集 - 就活転職対策アプリ

by CapCat LLC

Free

Prepare for the SPI aptitude test with this comprehensive question bank app. It offers section-specific practice and full-section tests, all accessible through convenient "study in your spare time" features. Get ready for your job or転職 (job change) with this free, no-registration-required tool.

All国語辞書

by ILHWAN CHO

Free

Access a comprehensive collection of Japanese dictionaries and encyclopedic resources. Search across multiple platforms including Weblio, Kotobank, and Wikipedia. Features a convenient search history for easy review and learning.