Tower of London test online: plan your moves

3 balls, 3 pegs of different heights and a picture of where the balls should end up. Rebuild that picture 12 times, in as few moves as you can. Your score shows how much of the work you did in your head before moving.

Start the Tower of London test

12 problems · about 4 min · mouse or trackpad

After problem 12 you see your score and can keep it with a free account.

12 problems · about 4 min · mouse or trackpad

The Tower of London needs a mouse or trackpad and room for 2 boards. Open this page on a computer to take it.

Start the Stroop test

Stroop works on a phone: say the ink color and ignore the printed word.

Goal above, your board belowClick a ball, then click a peg

How it works

A 1-move practice comes first and is not scored. Then a 3-second countdown and 12 problems that get longer as you go. About 4 minutes in all.

  1. 1 · Practice

    Learn the controls

    Click the blue ball to select it, then click the tallest peg to drop it there. That single move matches the goal and the practice ends.

  2. 2 · Each problem

    Copy the goal

    The goal arrangement sits above your board, drawn faded. Move balls until your board matches it exactly: every ball on the right peg, in the right order.

  3. 3 · The rules

    One ball, top only

    Only the top ball on a peg can move, one at a time. The tall peg holds 3 balls, the middle peg 2 and the short peg 1.

  4. 4 · Problems 1 to 12

    60 seconds each

    Each problem shows a minimum move count, from 2 on the first problem to 7 on the last four. Its 60-second clock starts at your first click on a ball.

A counter shows your moves beside the minimum. Reset puts the balls back where they started and sets the counter to 0, but the clock keeps running. Skip Problem moves on with 0 points. When the boards match, your move count appears and the next problem loads.

The task goes back to Tim Shallice's 1982 paper on specific impairments of planning. This version keeps the classic layout of 3 colored balls on 3 pegs of different heights, with its own set of 12 problems and its own points rule.

What it measures

Any problem can be solved by trial and error. Solving it in the fewest moves means working out the order of moves before the first one.

Planning

  • Looking ahead: picturing where each ball must go and which ball has to get out of the way first.
  • Sequencing: putting moves in an order that does not undo the ones before.
  • Holding a plan of several steps in mind while you carry it out.

Control

  • Holding back the obvious move when it leads away from the goal.
  • Noticing that a move went wrong and changing course before time runs out.
  • Working steadily against a 60-second limit on each problem.

Planning is usually grouped with the executive functions, the skills that organize and steer other thinking (Diamond, 2013). Longer problems ask for a longer plan, which is why the result screen splits your solved problems by length.

Age matters on tower tasks. In a computer version given to 7,703 adults aged 40 to 80, planning scores were highest in the 40s and lower in each older age group (Unterrainer et al., 2019).

A test, not a diagnosis.

Your score describes 12 problems on one day. It cannot diagnose or rule out any condition.

What you get

The result screen opens as soon as problem 12 is over.

On the result screen

  • A one-line reading of your planning and a marker on a scale from strong planner to needs support.
  • Problems solved, out of 12, and your score, out of 36.
  • Solved problems at each length, from 2 to 7 moves.
  • Your average extra moves on solved problems and your average planning time.
  • A panel for clinicians with each problem's moves, points and time, a table of score bands and a CSV download.

When you keep it

  • A free account saves it, and you can open it again from any device.
  • Placed under executive function in your results, next to Stroop, Trail Making and Card Sorting if you take them.
  • A next test is suggested when you continue, so your picture keeps growing.

How this version is scored

For every problem the test stores the minimum it showed, your moves, your time and whether the boards matched.

Points per problem
3 points when you match the goal in no more moves than the minimum shown, 2 with 1 extra move, 1 with 2 extra moves, and 0 with more moves, a skip or a timeout.
Total score
Your points over the 12 problems, from 0 to 36. The one-line reading uses 3 bands: 24 or more, 12 to 23, and below 12.
Problems solved
How many of the 12 you matched before the clock ran out, however many moves it took. This count, as a percentage, is the accuracy saved with your result.
Extra moves
On each solved problem, your moves minus the minimum shown, averaged over the problems you solved.
Planning time
The time from your first click on a ball to your first completed move, averaged over the problems. Time spent looking before that first click is not included.

Why moves count and speed does not. Points depend only on how many moves you make. Time works as a limit: a problem still open at 60 seconds scores 0, but a slow, exact solution earns the same points as a quick one.

About the score bands. The clinicians' panel also prints a table of 5 labelled score bands. They are not fitted to this version's problems, so read them as a rough guide. The result screen gives no percentile.

Before you start

Planning goes better with a clear head and a clear screen.

For a cleaner attempt

  • Use a computer with a mouse or trackpad and a window tall enough to show both boards.
  • Use the practice to get used to selecting a ball before you place it.
  • Work out the order of moves before you start moving: the points reward fewer moves, not speed.
  • Close other tabs and silence notifications until the result appears.

Interpret cautiously when

  • You are tired, unwell, rushed or interrupted.
  • Telling the red, green and blue balls apart is hard for you, although each ball also carries its color name.
  • Clicking small targets is hard with your hand, pointer or assistive setup.
  • You have done this test before: the same 12 problems come up every time, so a second run is easier.

Questions

What does the Tower of London test measure?

It measures planning: working out a sequence of moves before you make them. Reaching the same goal in fewer moves means more of the work happened in your head. The task also draws on holding a plan in mind and on resisting a tempting first move, which is why it is grouped with tests of executive function.

What is a good score on the Tower of London test?

On this version a higher score out of 36 and more problems solved are better, and the result screen reads your total in 3 bands. Published norms come from other versions with different problems and scoring, such as the Drexel University edition, and studies of those versions find that age and education change scores. So this page prints no norm table, and your result is not turned into a percentile.

Can I do the Tower of London test on my phone?

No. Selecting and placing balls on 2 stacked boards needs a computer with a mouse or trackpad, so the tests hub asks for one. On a phone you can take the Stroop test now and come back to this one on a computer.

Can I retake the Tower of London test?

Yes, from the tests hub, as often as you like. The same 12 problems appear in the same order each time, so a second attempt benefits from remembered solutions as well as from practice. Your first score is the most informative one.

Sources

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