Cortex: N-Back Brain Training

Cortex is an offline brain-training app: dual N-Back, a Stroop test, Schulte tables, a reaction time test and an RSVP speed reader, plus Sudoku, Nonogram and Word Search puzzles. No account, no internet, no tracking: nothing leaves your phone.
Also known as: n-back memory test, Stroop effect test, Schulte grid, reflex test, speed reading trainer.

Seventeen focused brain games and classic puzzles, plus Peak Hours: a personal cognitive instrument you won't find in other brain trainers. Try everything free for 3 days, then unlock it all with a single purchase. No subscription, no ads, no accounts, and nothing leaves your device.

PEAK HOURS
A quick reaction check you can take any time of day. Over time it charts when your mind is sharpest and reveals whether you're a morning lark, a night owl, or steady all day. Fully private, stored only on your phone.

THE GAMES
Memory, focus, reading, timing and spatial skills, each built around a real task:
- N-Back, Sequence Memory and Remember-To for memory
- Stroop, Track and Peripheral Vision for attention
- Schulte Table and Speed Reader for visual scanning and reading
- Mental Rotation for spatial reasoning
- Inner Clock for your sense of time
- Number Sequences for pattern reasoning

SKILL DRILLS
- Mental Math: learn a real trick, then drill it
- Speed Math and Estimation for arithmetic fluency and number sense

CLASSIC PUZZLES
- Nonogram: solve the number clues to reveal a hidden picture
- Sudoku and Word Search, as pure puzzles

3-DAY FREE TRIAL, THEN PAY ONCE
Every game is unlocked free for 3 days. Keep them all forever with a single one-time purchase. No weekly trials, no renewing subscription, no surprise charges.

PRIVATE BY DESIGN
No accounts, no analytics, no advertising, no third-party trackers. The app works fully offline and your stats stay on your phone. Privacy here isn't a setting you switch on; it's how the app is built.

BUILT FOR FOCUS
A precision design made for concentration, not a candy-coloured slot machine. Make it yours with multiple themes, light or dark, and a custom accent colour. Track your personal bests at your own pace.

Now fully available in nine languages.