Statistics on Difficulty of Sudokus

There is now reliable, objective way to measure the difficulty of a given Sudoku. Therefore these statistics compiled from how fast or slow humans solved the Sudokus on the one hand, and how many people solved a given Sudoku on the other hand.

Average Solving Time

All times are given in Seconds.

Overall Statistics

Average	649
Std. Deviate	111
Minimum	412
Maximum	2513

Easiest and Hardest Sudokus

The Sudokus that were solved fastest/slowest on average.

	Easiest		Hardest
No	Mean Time [s]	Sudoku	Mean Time [s]	Sudoku
1	412	2010-08-04	2514	2011-01-22
2	421	2009-08-04	1769	2006-10-14
3	423	2011-07-31	1248	2010-12-25
4	424	2011-06-12	1239	2010-04-21
5	428	2006-10-04	1234	2011-06-30
6	431	2007-04-03	1206	2009-11-18
7	434	2007-01-18	1155	2012-03-27
8	435	2011-03-25	1136	2012-02-04
9	435	2009-11-15	1039	2008-10-29
10	439	2009-12-03	1013	2012-02-23
11	440	2010-10-20	1001	2012-02-28
12	440	2006-11-06	985	2012-02-14
13	445	2009-12-09	981	2012-03-01
14	445	2010-01-13	972	2007-09-07
15	445	2007-06-16	971	2009-12-07

Number of People Who Solve a Sudoku

Most Difficult Sudokus

These Sudokus have been solved lest often: