Digit Span

About the Digit Span exercise

Someone reads out a phone number, a booking reference, a room number, or a PIN, and it has to be held just long enough to write down or key in. Holding a short string of digits in order, by ear, is one of the plainest everyday uses of working memory. After a stroke, a brain injury, or with attention changes, the string can slip before the last digit has even been heard.

Digit Span is a free online digit span exercise for practicing the forward and backward digit span task. A voice reads a string of digits at a steady pace, and the person says it back in the same order or in reverse. In span mode the strings grow one digit at a time until every string at a length is missed, so each round ends at the longest string said back correctly.

What is a digit span task?

A digit span task reads a string of digits aloud, about one a second, and asks the person to repeat it. Forward digit span asks for the same order. Backward digit span asks for the reverse order, so the string has to be held and turned around at the same time.

The strings start short and get one digit longer after each length is passed. The longest string repeated correctly is the span. The format is widely used to look at attention and working memory, which is why it appears in standardized test batteries; this tool uses the format for practice only.

1. Listen to the whole string without writing anything down.
2. Wait for the tone that marks the end of the string.
3. Say the digits back, or tap them on the keypad: forward in the same order, backward from the last digit to the first.
4. Two strings are given at each length. Passing either one moves the round up a digit.
5. The round ends when both strings at a length are missed, or at the longest length set.

What Digit Span practices

Holding a sequence in order

Forward span asks for every digit in its place. Each new digit has to join the string without pushing the earlier ones out, and the order matters as much as the digits themselves.

Working with what is held

Backward span adds a second job: the string is held and reversed before it is said. Most people manage a shorter string backward than forward, so the backward preset starts at two digits.

Auditory attention

Every digit arrives once, by ear, at a pace of 0.7 to 1.5 seconds. There is nothing to look back at unless the digits are shown, so attention has to stay on the voice until the tone.

How the tool works and what it records

Three free presets: Forward span (3 to 9 digits), Backward span (2 to 8 digits), and Practice at four digits (8 strings, all four digits long). In span mode the round starts short and adds one digit each time a length is passed, with two strings at each length, and stops when every string at a length is missed or at the longest length set. Pro unlocks the dials: start length 2 to 9, longest 3 to 12, one to three strings at each length, fixed-length practice of 5 to 15 strings, pace 0.7 to 1.5 seconds per digit, and a 0 to 10 second delay before answering. Always free: digits heard, shown, or both; tap or therapist-marks response; large print; and a test-the-voice button.

Strings use the digits 1 to 9, with no digit repeated in a string of nine or fewer and no runs of three counting up or down. A tone marks the end of each string; the person taps the answer on a keypad or says it while a partner marks it. Results show the longest span, strings correct, digits in place, and accuracy at every length. Signed-in users get 5 free rounds per tool per day; Pro removes the cap, adds a PDF therapist sheet (forward strings of 3 to 9 digits and backward strings of 2 to 8, two at each length, with the reversed answer printed), and saves rounds to a session log.

Screen or paper?

The screen suits a steady, repeatable voice: the pace never drifts, a tone marks the end, the stop rule runs itself, and accuracy at every length is worked out automatically. Paper suits a partner reading strings aloud at a natural pace, sessions without a device or speakers, people who follow a live voice more easily, and a marked sheet to keep.

The printable version is the Auditory Working Memory worksheet set on rehabworksheets.com, and there is a free auditory working memory worksheet to try first, with no email required.

Using it well

• Test the voice before the first round. The test-the-voice button reads three digits at the chosen pace and ends with the tone. Check that every digit is clear through the device's speaker before starting.
• Run forward before backward. Backward span asks more of working memory, so start with the forward preset. Move to backward once forward strings feel steady, and expect the backward span to be a little shorter.
• Turn the screen away in therapist-marks mode. Therapist-marks mode shows the answer on screen for the partner. Keep the device turned toward the partner while the person says the string, so the answer is not read off the screen.
• Use shown digits when listening is the barrier. The shown option presents each digit on screen, one at a time, with no voice, and heard and shown pairs the two. They are different tasks, so compare spans only between rounds run the same way.
• Compare like with like. The longest span depends on direction, pace, and whether digits are heard or shown. Keep those the same from session to session when looking at change, and note any delay before answering.

Common questions