Last updated: April 2026
Who we are
Sudoku Tools is one of a number of sites operated by Cheltenham Systems. References to "we", "us", and "our" in these terms mean Cheltenham Systems. For support or questions specifically about Sudoku Tools, please contact support@sudokutools.com.
Who this service is for
Sudoku Tools is aimed at older children and adults. There is nothing on this site of a sensitive or adult nature. We do not require you to declare your age to use the service.
If you are under 18 and wish to purchase a subscription or course, please do so with a parent or guardian's knowledge and consent.
Your account
You are responsible for keeping your password secure and for any activity that takes place under your account. If you believe your account has been compromised, contact us immediately.
Please use one account per person. Creating multiple accounts to circumvent any restrictions is not permitted.
Free use — no registration required
You can try Sudoku Tools without registering. A small selection of fixed puzzles is available to anyone visiting the site, with no account, no email address, and no personal data collected. This is purely to let you try the interface and see whether the site is for you.
Free features — registered users
Registering gives you access to the full puzzle library, basic progress tracking, and previews of course content — all free of charge. Registration requires only an email address and a display name. We reserve the right to adjust what is included in the free tier over time, with reasonable notice to registered users.
Monthly subscription — £10.00/month
A monthly subscription gives access to subscriber features including adaptive difficulty, unlimited puzzle hints with technique explanations, and full progress tracking.
- Billing is monthly via Stripe. Your card is charged at the start of each billing period.
- You may cancel at any time. If you cancel before the halfway point of your current billing month, that month's charge will also be refunded. If you cancel after the halfway point, access continues until the end of the billing period with no further charge.
- Refunds are returned to your original payment method, typically within 5–10 business days.
Course purchase — £150.00
A course purchase gives access to the full Sudoku Tools course content for five years from the date of purchase, plus all subscriber features for the first twelve months.
- After the first twelve months, course content remains accessible but subscriber features require a separate monthly subscription.
- If you are not satisfied with the course content for any reason, contact us and we will issue a refund — no argument, no quibble. The refund will be the full purchase price of £150, minus £10 for each complete month of subscriber features you have used. This ensures the course refund covers the course itself, while any subscription time genuinely used is charged at the standard rate.
- The five-year course access period begins on the date of purchase and is not paused or extended for any reason.
Intellectual property
All puzzles, course content, videos, diagrams, and software on Sudoku Tools are the intellectual property of Cheltenham Systems.
Purchasing a subscription or course gives you a personal, non-transferable licence to access and use that content for your own learning. Specifically:
- You may watch course videos and work through lessons for your own use.
- You may not copy, reproduce, redistribute, or share course content — including videos, diagrams, or lesson text — with others.
- You may not share your account login with others or allow others to access paid content through your account.
- You may not scrape, download in bulk, or systematically reproduce puzzles or any other content from the site.
Acceptable use
You agree not to use Sudoku Tools to:
- Attempt to gain unauthorised access to any part of the service or its underlying systems
- Interfere with the service or other users' access to it
- Submit false or misleading information during registration
- Use automated tools to interact with the service in ways not intended (e.g. scripted puzzle solving at scale)
Availability
We will make reasonable efforts to keep Sudoku Tools available, but we do not guarantee uninterrupted access. The service may be unavailable occasionally for maintenance, updates, or reasons outside our control.
Changes to the service or these terms
We may update these terms from time to time. For material changes, we will notify registered users by email before they take effect. Continued use of the service after changes take effect constitutes acceptance of the updated terms.
We may change or discontinue features of the service. If we discontinue a paid feature you have specifically subscribed for, we will offer a pro-rata refund for any unused period.
Termination
You may delete your account at any time via the Account page. This removes all your data from our systems.
We reserve the right to suspend or terminate accounts that breach these terms, particularly in cases of abuse, fraud, or misuse of the service. In such cases, subscription fees already paid will not be refunded.
Limitation of liability
To the extent permitted by law, Cheltenham Systems will not be liable for any indirect, incidental, or consequential losses arising from your use of Sudoku Tools. Our total liability to you will not exceed the amount you have paid us in the twelve months preceding any claim.
Governing law
These terms are governed by the laws of England and Wales. Any disputes will be subject to the exclusive jurisdiction of the courts of England and Wales.
Contact
For any questions about these terms, billing, or refunds:
support@sudokutools.com
For privacy-related queries, see our Privacy Policy.