In effect from 20 September 2026

Terms of use

MathPencil is published at mathpencil.com by HTPdevs. Using the site means accepting what follows. It is short, because a free study site does not need a long contract.

What you get

Permission to use MathPencil for your own purposes, personal or commercial, at no charge. There is no account to create, no licence to buy and no limit on how much arithmetic you do. We may change, add to or withdraw features at any time, and we do not promise the site will always be available.

Check your own arithmetic

MathPencil is offered as it is, with no warranty of any kind, including no warranty that a given answer is correct, or that the site is fit for any particular purpose. It is built carefully and the two engines behind it are described openly on the adding machine page, but software has faults, and a figure on a screen is not professional advice. Do not rely on MathPencil alone for anything financial, medical, structural, legal or otherwise consequential. Verify a result that matters.

What you agree not to do

• Attempt to interfere with the site, its server, or anyone else's use of it, including by automated request volume intended to degrade it.
• Present MathPencil as your own product, or remove or obscure its attribution.
• Use the site in a way that breaks the law where you are, or that infringes someone else's rights.
• Interfere with, mask or automate interaction with the advertising on the page, including generating clicks or impressions that are not genuine.

Ownership

The MathPencil name, its wordmark, its design and its source code belong to HTPdevs. The numbers you key in are yours; we never receive them, as set out in the privacy policy.

Advertising and other sites

The page carries advertising served by Google, and an ad may link somewhere we have no control over. We are not responsible for the content, products or practices of any site an advertisement leads to, and a link is not an endorsement.

Liability

To the fullest extent the law allows, HTPdevs is not liable for any loss or damage arising from your use of MathPencil or from reliance on a result it produced, including lost profit, lost data, or consequential loss of any kind. Nothing here limits liability that cannot lawfully be limited, and if you are a consumer, this does not affect the statutory rights you have where you live.

Changes to these terms

If these terms change in a way that matters, the date at the top of this page changes with them. Continuing to use the site after that is acceptance of the new version.

Getting in touch

Questions about these terms, a bug, or a key that should exist: support@htpdevs.com.