Terms of use

You may use 1plus1 freely, for personal or professional purposes, without registering. You may share links to any calculation.

• Copy the site’s text, structure or calculator content to republish it elsewhere.
• Send automated traffic that degrades the service for other visitors.
• Present results from this site as professional advice you have given.

The calculators are provided as they are, without warranty of any kind. We work carefully and test the formulas, but we cannot guarantee that every result is correct in every context, nor that the site is always available.

To the extent permitted by law, we are not liable for any loss arising from the use of a result obtained here. Decisions with financial, medical, legal or structural consequences should be confirmed with a qualified professional.

The name, the design, the interface, the texts and the calculator definitions belong to 1plus1. Mathematical formulas themselves are not owned by anyone; our expression and explanation of them is.

These terms may change as the site grows. The date below indicates the current version.