Difficulty Levels & Awards Update (January 2026)

[i707107]

On Award page, if I click any award, an error message "The page you are looking for cannot be found..." shows.

[teoet6]

I really liked the old color scheme on the "progress" page. I find the new "monochrome" one very dull. It would be nice if a "classic" color scheme that imitates the old look is added.

I've always felt like difficulty ratings were incorrect, so I hope the new rating system works better : )

[Incompleteusern]

Seconding the request for a rainbow color scheme with the hardest problems being red and the easiest being purple, I think that would be very lovely.

[GNFS]

If bigger level means harder, I still feel like older problems are overweighted. Like Problem 223 is way easier than Problem 600 (which stumped me for years).

[i707107]

On Award page, if I click any award, an error message "The page you are looking for cannot be found..." shows.

Thank you. Now, the clicks are disabled, and the list of people who received a particular award is not visible.

[Circling]

I agree that older problems' ratings are skewed. Problem 703 is objectively a harder version of 209, but it appears to be 5 levels under.

[rexcirus]

Levels ranks do not work: https://projecteuler.net/level=17

[Anonymoose]

Suggestion: Have the old difficulty levels viewable in some way, at least for the problems that were assigned one? Even if it's only in the problem view - maybe include it in the hover text on the information button as "Classic Difficulty" or "Legacy Difficulty" and put "N/A" for newer problems.

Having never had the emotional experience of solving a 100% difficulty problem, I'd like to keep the dream alive!

[thedoctar]

I would like to remark on what I think is a discrepancy in the current difficulty level system.

PE943 is rated 38, 101 solvers, and PE910 is rated 37 with 102 solves.

How can it be that a problem posted 30 weeks later and having only one less solver is considered more difficult?

Seems that the calibration of the metric is not quite correct.

Also I feel that PE910 is significantly more difficult. Looking at the solve times one would also come to that conclusion.

[amaliev]

The Dating Game award appears broken for me, I've triple checked on my history that I have solved a problem on all 31 days of the month, but the badge progress says 30/31. Maybe there's a time zone discrepancy?

As an aside, for this award it would be nice to have an indicator of which days you've solved a problem on and which days you're missing.

[TitanCode]

Conquering Difficulties award wording not consistent: I see “at least one problem at twenty five difficulty levels” and “Progress: 26 / 30“

I mentioned this earlier, but given how fast other things are fixed, it seems to have been overlooked.

Thank you for your great work on this site. I am having loads of fun and learning a lot solving problems.

[euler]

@amaliev: You are currently missing the 11th. It's almost too late for you now, but it will certainly help other. Upon your suggestion, I have added a feature that if the number of missing dates is five or less it shows the dates that need to be solved.

@TitanCode: Sorry about that. You are right. I forgot about it. I guess we have to decide if I change the wording to say thirty levels to match what the script is checking for or or leave the wording and change the checking script to award it at twenty-five levels.

[Arxyj]

It will probably become more stable over time. But its kinda annoying now.
When i first solved problem 160, it was difficulty 33. Yesterday, when i solved 163, they vere 31 and 30. Today both are 29.
I dont really care about the difficulty itself. The problem is its ruining my progress towards the Counquering Difficulties award.

[hacatu]

The progress page is not updated to have a row for difficulty level 39:


Also, I don't really like having a difficulty level with only 1-10 ish problems, so maybe the max level should be able to exceed 25 problems

[amic]

Another comment regarding the color scheme : it would be nice that the pinned problems now appear another way than red. Maybe another way to highlight them (like a thicker border), or use green for instance ?

Edit : I was talking about those in the “by level” grid, or those in the main grid when the “show heat map (all problems)” is not activated. Otherwise, the slight white instead of black is ok. Maybe boldface would help to spot them easily ?

[TitanCode]

There seems to be missing a level in the "Problem Solved by Levels". 39x 25 = 975, but problem 976 is present.

[hk]

Levels are 0 Indexed

[TitanCode]

> Levels are 0 Indexed

Yes. The top level named 39 (currently containing only problem 566) wasn't visible when I posted. Has been fixed meanwhile.

[TitanCode]

TL;DR suggestion: Only change the difficulty settings at a set time once per week.

Perfecting Difficulties Award:

I agree with Arxyj (above): The unstability of the difficulty setting is annoying. On an almost daily basis my level for the “Perfecting Difficulties“ award shifts between 25 to 27 (of 28). Last night it was at 27, so I set out trying to solve the ‘missing’ problem. Almost made it, but had to go to bed. This morning the difficulty ratings have had yet an earthquake and I am now at 25 of 28, and the almost-solved problem is no longe a missing difficulty. Getting the award as a result of yet an earthquake will also be less satisfying. Only changing the difficulty settings at a fixed and announced time for instance once per week would help a lot. As of now it is annoying to be so near and have had the award moved away literally overnight.

[amaliev]

@euler Thank you for the update! This is very helpful. Are you by any chance using UTC time to determine the dates for the Dating Game award? That would explain the discrepancy - this could be confusing since the solve times under Progress > History are in the user's local time.