Magnitude Comparison test online: which number is larger

2 digits from 1 to 9 appear side by side and you pick the larger one as fast as you can. How much longer you take when the digits are close is called the distance effect.

Start the Magnitude Comparison test

96 pairs · about 4 min · arrow keys or touch

After the last pair you see your accuracy and timing, and can keep them with a free account.

+ 38
3 or 8: the right arrowPick the larger digit

How it works

8 practice pairs come first, each followed by a green or red flash, then a 3, 2, 1 countdown and 96 scored pairs. Every pair waits for your answer, so the pace is yours: about 4 minutes.

  1. 1 · Before each pair

    Look at the +

    A + sits in the centre for half a second. Keeping your eyes there puts both digits in view the instant they appear.

  2. 2 · On a computer

    Arrow toward the larger

    Press the left arrow key when the left digit is larger and the right arrow key when the right one is. There is no time limit, but your speed is recorded.

  3. 3 · On a phone

    Tap the larger digit

    On a touch screen the 2 digits turn into buttons and you tap the larger one. The pairs and the scoring stay the same.

  4. 4 · 96 pairs

    Near and far pairs

    The 2 digits differ by 1 to 8. Each gap comes up 12 times, 6 with the larger digit on the left and 6 on the right, so close and far pairs weigh the same.

Once practice ends, nothing tells you whether you were right. A half-second blank follows each answer before the next +, and a thin bar at the top tracks your progress. The 96 pairs are shuffled on every attempt.

The task goes back to a 1967 study in which Moyer and Landauer timed people choosing the larger of 2 digits and found that close digits take longer than distant ones (Moyer and Landauer, 1967). That slowing is the distance effect, and it is the pattern this version is built to measure.

What it measures

Every pair asks the same question. What changes from pair to pair is how far apart the 2 digits are.

Speed and accuracy

  • Symbolic number sense: getting from a written digit to the quantity it stands for.
  • Accuracy on a comparison that very few adults get wrong.
  • Mean response time on the pairs you answered correctly.

The distance effect

  • How much longer close pairs, a gap of 1 or 2, take than far pairs, a gap of 5 to 8.
  • The slope of your mean time across all 8 gaps.
  • Whether your timing follows the size of the gap at all, the pattern most people show.

Digits are symbols, while clouds of dots are raw quantity. Research on maths difficulties keeps asking which of the 2 is harder for whom. Rousselle and Noël (2007) compared symbolic and non-symbolic comparison in children with maths learning difficulties, and Skagerlund and Träff (2016) found one group of children whose problems were limited to symbols, a pattern they read as trouble getting from the digit to its quantity.

A meta-analysis by Schneider and colleagues pooled studies that relate both kinds of comparison to maths competence (Schneider et al., 2017). This task is one of the 4 tasks of the dyscalculia check, where its accuracy is read next to dot comparison, arithmetic and the number line.

A test, not a diagnosis.

One run of digit comparisons describes that run. It cannot establish or exclude dyscalculia or any other diagnosis.

What you get

Your times are on screen as soon as the 96th pair is answered.

On the result screen

  • Your accuracy, your mean response time on correct answers and your distance effect in milliseconds.
  • A bar chart of your mean time at each gap from 1 to 8.
  • Your mean time on close pairs and on far pairs, side by side.
  • No verdict and no comparison with other people: the screen says it reports this attempt only.
  • A data panel with the slope per unit of distance and a table per gap, plus a CSV file of every pair.

When you keep it

  • Stored with a free account and reachable from any device once you sign in.
  • Shown among the number tasks in your results, next to the others you have taken.
  • The next test is suggested straight away, so the set of results keeps growing.

How this version is scored

Each pair logs the 2 digits, the gap, your key or tap, the device type and your time. The figures below use the 96 main pairs only.

Correct answer
You chose the larger digit. The 2 digits are never equal, so every pair has exactly one right answer.
Response time
From the moment the digits appear to your key press or tap. Only correct answers enter the time averages.
Distance effect
Your mean time on close pairs, gap 1 or 2, minus your mean time on far pairs, gap 5 to 8. A positive number means the close pairs took longer.
Slope
A straight line fitted to your mean time at each gap from 1 to 8, in milliseconds per unit of distance. In the usual pattern it is negative, because times fall as the gap grows.
Minimum for scoring
At least 60% of the 96 pairs, 58 or more, must be right. Random pressing gets about half right in a 2-choice task, so below that line the distance effect and slope show as N/A.

Why there is no verdict. This setup has no published adult norms, so the result screen gives your numbers and does not label them as high or low.

Keys and taps differ. Pressing an arrow key and tapping a digit are different movements, and the device type is saved with every pair. Compare your attempts on the same kind of device.

Balanced gaps. Each gap from 1 to 8 appears 12 times. An earlier version showed every one of the 36 digit pairs 4 times, which made close gaps far more frequent than far ones; the current set weighs them equally.

Before you start

The task is about speed, so a steady setup counts for more than effort.

For a cleaner attempt

  • On a computer, rest 2 fingers on the left and right arrow keys before the countdown.
  • On a phone, hold it the same way for the whole run so every tap is the same movement.
  • Keep your eyes on the + between pairs, so you never have to search for the digits.
  • Answer as soon as you know; there is no prize for checking a pair twice.

Interpret cautiously when

  • You switched devices partway, or used keys on one attempt and touch on another.
  • Reading digits takes extra effort for you, for reasons of vision or reading access.
  • Motor speed, a tremor or a small screen slowed your presses or taps.
  • You were tired, anxious about numbers or interrupted during the pairs.

Questions

What does a magnitude comparison test measure?

It measures how quickly and accurately you judge which of 2 written numbers is larger. Researchers treat it as a measure of symbolic number sense: how directly a digit calls up the quantity it stands for. The distance effect, slower answers for close digits, shows that your decisions follow size.

What is the numerical distance effect?

It is the finding that people take longer to compare digits that are close, such as 4 and 5, than digits that are far apart, such as 1 and 9. Moyer and Landauer reported it in 1967. Here it is your mean time on gaps of 1 or 2 minus your mean time on gaps of 5 to 8.

Can I do the magnitude comparison test on my phone?

Yes. On a touch screen the 2 digits become buttons and you tap the larger one. Taps and key presses differ in speed, so compare later attempts on the same kind of device.

What is a normal score on a number comparison test?

Low accuracy on such a simple comparison is unusual in adults, so most of the interest is in timing. This version has no adult norms yet, and its result screen shows your own accuracy and times without a percentile. In the dyscalculia check, accuracy under 85% reads as below typical and under 75% as clearly below.

Sources

By Cristian Dominguez Rein-Loring, Creative Technology Lead · Updated October 12, 2026