What is ao5 and how is it calculated?

ao5 (average of 5) is the average of 5 consecutive solves, excluding the single fastest and slowest and averaging the remaining 3. For example, with 12.34, 11.02, 13.50, 12.50 and 10.98, you remove 10.98 and 13.50 and average 12.34, 11.02 and 12.50 to get 11.95. Rankings for 3×3 at WCA competitions are also decided by this ao5.

What’s the difference between ao12 and ao5?

ao12 is the average of 10 solves out of 12 consecutive ones, with the fastest and slowest removed. Because it uses more solves than ao5, lucky fast or unlucky slow solves have less effect, so it’s closer to your true skill. In practice it’s common to look at both ao5 and ao12.

mo3 (mean of 3) is the simple average of 3 solves with nothing removed. It’s used for events where only 3 solves are done at competitions, such as 6×6, 7×7 and blindfolded. If even one solve is DNF, the mo3 is DNF.

When does inspection result in +2 or DNF?

Under the WCA Regulations, inspection is 15 seconds. Starting the solve after 15 seconds but by 17 seconds gives +2 (2 seconds added), and after 17 seconds gives DNF (no result). This timer applies penalties automatically with the same rules and alerts you with a sound at 8 and 12 seconds.

What happens to ao5 when there’s a DNF?

A DNF is treated as the slowest result. If an ao5 has one DNF, that DNF is removed and the remaining 3 are averaged. With two or more DNFs, they can’t all be removed, so the ao5 is DNF as well.

What are BPA and WPA?

BPA (Best Possible Average) is your ao5 if the 5th solve is the fastest, when the first 4 times are known. WPA (Worst Possible Average) is your ao5 if the 5th solve is the slowest or a DNF. Enter a target ao5 in this timer and it also shows what time you need to beat on the 5th solve.

How do I turn R', R2 and Rw in a scramble?

Hold the cube with white on top and green in front. R turns the right face 90° clockwise as seen when looking directly at that face, R' (“R prime”) turns it 90° counterclockwise, and R2 turns it 180°. Rw, used on 4×4 and larger, turns the two right-most layers together. U is the top, D the bottom, L the left, F the front and B the back face.

Can I use it on a phone?

Yes. Press and hold the timer area, then lift your finger when the numbers turn green to start, and touch anywhere on the screen to stop. While timing, the whole screen becomes the timer and doesn’t scroll, so you won’t miss the stop even if your finger slips.

Rubik’s Cube Timer | Scramble Generator, 15-Second Inspection & ao5/ao12 Calculation (2×2, 3×3, 4×4, One-Handed)

The Rubik’s Cube Timer is a browser-based timer for speedcubing practice. It generates scrambles for 2×2 (11 moves), 3×3 (25 moves) and 4×4 (40 moves including Uw, Rw and Fw), and shows a net diagram of the cube after scrambling. Hold the space bar or press and hold your phone screen until it turns green, release to start, and press again to stop. It supports the same 15-second inspection as the WCA Regulations, automatically adding +2 past 15 seconds and DNF past 17 seconds, with audio alerts at 8 and 12 seconds. Records are kept per puzzle, with best and worst singles plus the current and best mo3, ao5, ao12, ao50 and ao100 (averages excluding the top and bottom 5%). From your last 4 solves it also shows “your ao5 if the next solve is the fastest (BPA) or the slowest (WPA)” and “the 5th time you need to hit a target ao5”. Includes a tab that calculates ao5 and ao12 from pasted times, CSV export, and a guide to reading scramble notation. Records are stored only in your browser.

SCRAMBLE (25 moves)

…

Net after turning with white on top and green in front

0.00

Press the space bar (on phones, tap the box below) to start inspection

3×3 records

0 solves (DNF 0)

Best

Mean (excl. DNF)

Worst

	Current	Best
mo3	-	-	3 more
ao5	-	-	5 more
ao12	-	-	12 more
ao50	-	-	50 more
ao100	-	-	100 more

Times

You can also add times measured with another timer, such as a Stackmat.

No records yet

Settings

Use inspection (15 s)Automatically adds +2 past 15 seconds and DNF past 17 seconds (same as WCA)Beep at 8 and 12 secondsReplaces the judge’s calls at competitions (once at 8 s, twice at 12 s)Hide time while timingFor those distracted by the running numbers

Hold timeTo prevent false starts, it turns green after holding for this long

Records and settings are stored only in this browser (localStorage) and are never sent to a server. They’re kept separately for each puzzle type.

How to read scramble notation

Hold the cube with the white face on top and the green face in front, and turn the named face 90° “clockwise as seen when looking directly at that face”.

UUp · “you”Center color: white

DDown · “dee”Center color: yellow

RRight · “ar”Center color: red

LLeft · “el”Center color: orange

FFront · “ef”Center color: green

BBack · “bee”Center color: blue

R … right face 90° clockwise
R' (“R prime”) … 90° counterclockwise
R2 … 180° (either direction is the same)
Rw (4×4) … the two right-most layers together 90° clockwise. Rw' and Rw2 work the same way

ABOUT

About Rubik’s Cube Timer | Scramble Generator, 15-Second Inspection & ao5/ao12 Calculation (2×2, 3×3, 4×4, One-Handed)

The Rubik’s Cube Timer is a browser-based timer for speedcubing practice. It generates scrambles for 2×2, 3×3, 4×4 and 3×3 one-handed, shows them as a net diagram, and times your solves with the space bar or a tap on your phone. It supports the same 15-second inspection as the WCA (+2 past 15 seconds, DNF past 17 seconds), and calculates the current and best mo3, ao5, ao12, ao50 and ao100, how much your ao5 can improve or worsen with the next solve based on your last 4 (BPA and WPA), and even the time you need for a target ao5.

How to use Rubik’s Cube Timer | Scramble Generator, 15-Second Inspection & ao5/ao12 Calculation (2×2, 3×3, 4×4, One-Handed)

1Choose a puzzle (3×3, 2×2, 4×4 or 3×3 one-handed)
2Turn the cube following the displayed scramble, holding it with white on top and green in front (you can check against the net diagram)
3Press and release the space bar (on a phone, the timer area) to start the 15-second inspection (it can be turned off in settings)
4When you’re ready, press and hold, then release when the numbers turn green to start
5When solved, press any key or tap anywhere on the screen to stop. The record and the next scramble appear automatically
6Use the ao5/ao12 table and “What will your ao5 be after the next solve?” to see how many seconds you are from your goal

Great for

Logging each time plus ao5 and ao12 while practicing the Rubik’s Cube
Getting used to the same 15-second inspection and +2/DNF as in competitions (WCA)
Timing solves without installing an app when you only have a phone
Finding out, after the 4th solve of a competition round, what time you need on the 5th to reach your target average
Pasting times measured with another timer to recalculate ao5 and ao12
Keeping one-handed (OH), 2×2 and 4×4 records separate from 3×3
Checking how to read scramble notation (R, R', R2, Rw)

Good to know

Scrambles are generated as random move sequences (25 moves for 3×3). This differs from TNoodle’s random-state scrambles used at WCA competitions, so please use them for practice.
Averages follow WCA and csTimer: 5% of all times (rounded up) is removed from both the top and the bottom, and the rest are averaged. ao5 and ao12 remove 1 from each end, ao50 removes 3 and ao100 removes 5. If there are more DNFs than can be removed, the average is also DNF.
Times are truncated to 1/100 second for display and calculation, and averages are rounded to 1/100 second.
Inspection penalties are based on the time from the start of inspection to the start of the solve (over 15 seconds up to 17 seconds is +2, over 17 seconds is DNF). You can add or remove +2 and DNF later in the list.
The browser timer measures using the moment keys are pressed and released, so screen rendering lag is not included, but the latency of the keyboard or touch panel itself (a few to several tens of milliseconds) is. It is not a substitute for official results.
Records are stored only in this browser’s localStorage and are never sent to a server. Clearing browser data also deletes your records, so save them as CSV if you want to keep them.

Questions this tool answers

Use Rubik’s Cube Timer | Scramble Generator, 15-Second Inspection & ao5/ao12 Calculation (2×2, 3×3, 4×4, One-Handed) for searches like these:

Time Rubik’s Cube solves in the browser
Learn how to calculate ao5
Understand the difference between ao5 and ao12
Learn the inspection +2 and DNF rules
Find the time needed on the last solve to reach a target ao5
Generate a 3×3 scramble
Learn how to read scramble notation like R' and Rw
Use a cube timer on a phone without installing an app

FAQ

What is ao5 and how is it calculated?: ao5 (average of 5) is the average of 5 consecutive solves, excluding the single fastest and slowest and averaging the remaining 3. For example, with 12.34, 11.02, 13.50, 12.50 and 10.98, you remove 10.98 and 13.50 and average 12.34, 11.02 and 12.50 to get 11.95. Rankings for 3×3 at WCA competitions are also decided by this ao5.
What’s the difference between ao12 and ao5?: ao12 is the average of 10 solves out of 12 consecutive ones, with the fastest and slowest removed. Because it uses more solves than ao5, lucky fast or unlucky slow solves have less effect, so it’s closer to your true skill. In practice it’s common to look at both ao5 and ao12.
What is mo3?: mo3 (mean of 3) is the simple average of 3 solves with nothing removed. It’s used for events where only 3 solves are done at competitions, such as 6×6, 7×7 and blindfolded. If even one solve is DNF, the mo3 is DNF.
When does inspection result in +2 or DNF?: Under the WCA Regulations, inspection is 15 seconds. Starting the solve after 15 seconds but by 17 seconds gives +2 (2 seconds added), and after 17 seconds gives DNF (no result). This timer applies penalties automatically with the same rules and alerts you with a sound at 8 and 12 seconds.
What happens to ao5 when there’s a DNF?: A DNF is treated as the slowest result. If an ao5 has one DNF, that DNF is removed and the remaining 3 are averaged. With two or more DNFs, they can’t all be removed, so the ao5 is DNF as well.
What are BPA and WPA?: BPA (Best Possible Average) is your ao5 if the 5th solve is the fastest, when the first 4 times are known. WPA (Worst Possible Average) is your ao5 if the 5th solve is the slowest or a DNF. Enter a target ao5 in this timer and it also shows what time you need to beat on the 5th solve.
How do I turn R', R2 and Rw in a scramble?: Hold the cube with white on top and green in front. R turns the right face 90° clockwise as seen when looking directly at that face, R' (“R prime”) turns it 90° counterclockwise, and R2 turns it 180°. Rw, used on 4×4 and larger, turns the two right-most layers together. U is the top, D the bottom, L the left, F the front and B the back face.
Can I use it on a phone?: Yes. Press and hold the timer area, then lift your finger when the numbers turn green to start, and touch anywhere on the screen to stop. While timing, the whole screen becomes the timer and doesn’t scroll, so you won’t miss the stop even if your finger slips.

Special Thanks

SOLO GUILD | サービス作るAIエンジニア

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