Problem 709

Release date: Sat, 04 Apr 2020 16:00:00 +0000

Problem 708

Release date: Sat, 28 Mar 2020 13:00:00 +0000

Daylight Saving Time (Sat, 28 Mar 2020)

In contrast to previous years, the Project Euler release schedule will not observe the UK daylight saving time that is due to come in effect on Sunday 29th March 2020. From problem 709 onwards, release times will follow a pattern based on UTC. We hope this gives a more consistent experience for our international community.

(Saturday 28 March 2020: Daylight Saving Time)

Problem 707

Release date: Sun, 22 Mar 2020 10:00:00 +0000

Problem 706

Release date: Sun, 15 Mar 2020 07:00:00 +0000

Problem 705

Release date: Sun, 08 Mar 2020 04:00:00 +0000

Problem 704

Release date: Sun, 01 Mar 2020 01:00:00 +0000

Maintenance Notice (Mon, 14 Oct 2019 00:00:00 +000)

On Tuesday evening 15 October 2019 (UK time), Project Euler will be inaccessible for maintenance due to an internal migration to a new VPS. Although we have been happy with the general performance on the current server, by moving to a more powerful server we are hoping that this will provide a stable environment for quite some time to come.

After the DB migration and testing has been completed it will be necessary to update the DNS on the VPS cluster. For most people this should happen quickly, but fully propagating throughout the global network means that some members may have to wait longer. Whilst your local DNS has not been updated you will continue to point at the old server, which will remain in maintenance status. So as soon as Project Euler appears to be back online you will know that your DNS has been updated; you will be on the new server and able to continue solving problems. Due to the way we are handling this there should be no data loss.

Whilst the main website is inaccessible we would remind you that a static version of the problems can be found at The problem set is up-to-date and although it will not update your profile, you are able to check answers. This link will appear on the maintenance notice page when it appears.

We hope that the move goes smoothly, but we would ask for your patience and understanding if we encounter any issues.

(Monday 14 October 2019: Maintenance Notice)

DB Migration Issue (Sun, 25 Aug 2019 00:00:00 +000)

To keep the website running optimally it becomes necessary for our hosts to periodically migrate the DB to a new server. We are very grateful for their diligence in this matter and it has always happened in the past without incident. However, today it seems that some of the data on the new server became corrupt during the transfer. Consequently it was impossible to sign-in, giving the impression that your account no longer existed. Fortunately, all the data remained intact on the old server.

So once the issue had been reported our hosts were able to point the site back to the DB on the old server before carefully ensuring that all of the data was migrated properly this time.

We are very sorry for the inconvenience and the scare this might have caused some members when they thought for a moment that their accounts had disappeared.

The site is now pointing at the DB on the new server and it should all be working as expected. It is highly unlikely that any data has been lost during the migration, but if you solved any problems in the last day, then for your own peace of mind it is recommended that you check no progress has been lost.

(Sunday 25 August 2019: DB Migration Issue)

Pinning Problems (Tue, 20 Aug 2019 00:00:00 +000)

A change was made recently to the website that allows you to pin problems. This should be useful if you wish to return to a particular problem.

At the top of each problem page you will find a small icon in the top right corner allowing you toggle between pin/unpin. Once a problem is pinned the ID will appear in blue on the problems table page and it will be shaded blue on your Progress page. In addition, on the Archives page you can also filter problems by pinned. Please note that currently each member is limited to ten pins.

Hopefully this proves to be a useful addition to Project Euler. If you spot any issues, then please use the thread:

(Tuesday 20 August 2019: Pinning Problems)

Summer Break (Mon, 17 Jun 2019 00:00:00 +000)

Problem 677 on Saturday 29th June will be the last problem of this season. Project Euler will then take a summer break, returning with a new problem on Saturday 7th September.

(Monday 17 June 2019: Summer Break)