Number Memory
Memorize, then type back.
A number appears for a few seconds. Type it back. Each level adds one digit.
The Zehano number memory test is the classic digit span task. You see a string of digits, the screen clears, and you type back what you saw. The string gets one digit longer each round you get right. Your highest level is one measure of short-term verbal memory.
How to use the Number Memory Test
- Watch the digits. A number appears on screen for a few seconds. Read it carefully.
- Wait for the prompt. The number disappears. A text box appears asking you to type it.
- Type the number. Enter exactly what you saw. Spaces optional; order matters.
- Continue. Get it right, the next round adds a digit. Get it wrong, the game ends.
- Track your best. Your highest level reached saves automatically in your browser.
Benefits
- Measures verbal working memory. A specific component of memory tied to language and abstract reasoning.
- Brief and reliable. Most adults complete a session in under three minutes.
- Tracks state. Performance reflects sleep, caffeine, and mental fatigue in real time.
- Free and private. Browser-only, scores stored locally, no signup.
The science
The digit span test traces back to the late 1800s and remains a core tool in cognitive assessment today. Most healthy adults can recall seven plus or minus two digits, which informed Miller's famous 1956 paper on the 'magical number seven' as a rough cognitive capacity limit. Modern work has refined this picture: true working memory capacity is closer to four chunks, but chunking strategies (grouping digits into familiar patterns like phone numbers or dates) often expand the apparent limit. The test is sensitive to sleep loss, anxiety, and several neurological conditions.
People who spontaneously chunk digits (210-555-1234 instead of 2105551234) reach higher levels through strategy rather than raw capacity. This is normal and well-studied.
Tips for best results
- Try to chunk longer strings into pairs or threes.
- Use rhythm or sub-vocalisation to keep the sequence active in mind.
- Test in a quiet room with no distractions.
- Compare your score across days, not single sessions.