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Digit Symbol Substitution Test

A key pairs symbols with digits. Match as many symbols to their digits as you can in 60 seconds.

Type
Attention
Takes
about 1 min
Result in
correct

Digit Symbol

~1 min

  1. A key pairs nine symbols with the digits 1 to 9. It stays on screen.
  2. A symbol appears: answer with its digit, on the keypad or your number keys.
  3. As many as you can in 60 seconds. Speed counts, and so does the right digit.

The pairing is shuffled every time you play.

Your result: — correct

How it's measured

Try another challenge

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  • Stroop Test

    Name the ink color, not the word.~1 min

  • Digit Span

    Repeat the digits, forward or backward.~2-4 min

  • Choice Reaction

    Pick the right square as fast as you can.~1 min

  • Visual Search

    Find the one T hidden among the Ls.~1 min

What is the Digit Symbol Substitution Test?

The Digit Symbol Substitution Test is a coding task: a key pairs each of the digits 1 to 9 with a simple symbol, and you translate one into the other as fast as you can for a fixed time. Versions of it have been part of psychological testing for decades. This page is a recreational version with symbols drawn for this site.

How this version works

The key stays at the top of the screen, each symbol above its digit. A symbol appears in the middle; you answer with its digit, on the keypad or with your number keys, and the next symbol appears at once. A wrong answer counts, and you carry on. You have 60 seconds. The pairing is shuffled every time you play, so a second run is a new key, not a remembered one.

How is your result calculated?

Your result is the number of symbols you matched correctly in 60 seconds. You also see how many you got wrong, your accuracy, and your average time per correct symbol, timed from the animation frame in which the symbol is drawn to the moment your key or finger goes down.

Is it the DSST or the SDMT?

Both. They are two directions of the same task. In the Digit Symbol Substitution Test (DSST) you are shown digits and draw the matching symbols; in the Symbol Digit Modalities Test (SDMT) you are shown symbols and give the digits. Drawing symbols on a phone would make your finger the bottleneck, so this version runs the SDMT way: symbol in, digit out. The paper versions usually run for 90 or 120 seconds; this one is 60.

What does it measure?

Mostly processing speed: how fast you can look something up and act on it. Scanning the key, holding pairs in mind and keeping your attention on a dull, repetitive job all play a part, and as a run goes on you start to remember pairs instead of looking them up.

What this test does not measure

It measures how many symbols you matched in 60 seconds, on your device, in one sitting. It isn't the clinical test, has no clinical norms, and says nothing about intelligence or any condition. For another timed attention task, try the Trail Making Test; for memory for digits, the Digit Span Test.

Questions

What does the Digit Symbol Substitution Test measure?
Mostly processing speed: how quickly you can look up a pair and respond. Visual scanning, attention and remembering pairs as you go also play a part.
What is the difference between the DSST and the SDMT?
The direction. The DSST shows digits and you draw symbols; the SDMT shows symbols and you give digits. This version works the SDMT way, because drawing on a phone would slow your finger, not your thinking.
What is a normal digit symbol score?
On the paper test used in the US health survey NHANES (2011–2014), adults aged 60 to 69 averaged 57 correct in 2 minutes, 70 to 79 averaged 48, and 80 and over averaged 40 (CDC, 2019). That version lasts twice as long and you draw each symbol, so a 60-second on-screen score isn't directly comparable.
Why does the key change every time?
So a second run tests the task, not your memory of the last key. Within a run the key stays the same, and remembering pairs is part of getting faster.
Can I use the keyboard?
Yes. Number keys 1 to 9 answer, on the top row or the number pad. The on-screen keypad works too.