Last updated: November 14, 2026
Proportion Calculator respects the work of writers, teachers, designers and developers, and we expect everyone who uses our site to do the same. We write our own guides, build our own calculators and design our own worksheets. Still, mistakes can happen. If you believe something on proportioncalculator.app infringes your copyright, this page explains how to tell us and what happens next.
We follow the US Digital Millennium Copyright Act (DMCA), specifically Section 512 of Title 17 of the United States Code.
How to Send a Takedown Notice
Email your notice to our copyright contact at proportioncalculator.marketing@gmail.com with the subject line “DMCA Takedown Notice”.
To be valid under 17 U.S.C. § 512(c)(3), your notice must include all six items below:
- Your physical or electronic signature, or the signature of a person authorized to act for the copyright owner.
- A clear description of the copyrighted work you believe we infringed, such as a link to the original article, image or worksheet.
- The exact URL on Proportion Calculator where the material appears, so we can find it quickly.
- Your full name, mailing address, phone number and email address.
- A statement that you believe in good faith that the use is not authorized by the copyright owner, its agent or the law.
- A statement that the information in your notice is accurate, and, under penalty of perjury, that you are the copyright owner or authorized to act for the owner.
Notices missing any of these items may delay our response, because we may need to ask you for the missing details first.
What Happens After We Receive Your Notice
| Step | What we do | Typical timing |
|---|---|---|
| 1 | Confirm we received your notice | Within two business days |
| 2 | Review the notice and the material | Within five business days |
| 3 | Remove or disable access to the material if the notice is valid | As soon as the review ends |
| 4 | Tell the person who provided the material, where possible | Right after removal |
Facts and Formulas Are Not Copyrighted
Before you send a notice, please keep one thing in mind. Under US copyright law, facts, ideas, methods and mathematical formulas are not protected by copyright, as the US Copyright Office explains in Circular 33. So, the cross product rule, the formula for a two proportion z test, or the value of the golden ratio belong to everyone.
What copyright does protect is the specific way someone expresses those ideas, such as their exact wording, original diagrams, code and worksheet layouts. That is what a valid notice should point to.
How to Send a Counter Notice
If we removed your material and you believe we made a mistake, you can send a counter notice under 17 U.S.C. § 512(g). Email it to proportioncalculator.marketing@gmail.com with the subject line “DMCA Counter Notice”, and include:
- Your physical or electronic signature.
- A description of the material we removed and the URL where it appeared before removal.
- A statement, under penalty of perjury, that you believe in good faith that we removed the material by mistake or because it was misidentified.
- Your name, address and phone number.
- A statement that you consent to the jurisdiction of the federal court for your district, or for any judicial district where we may be found if you live outside the United States, and that you will accept service of process from the person who filed the original notice.
When we receive a valid counter notice, we forward it to the person who sent the original notice. If that person does not file a court action within 10 to 14 business days, we may restore the material.
A Warning About False Claims
Please be careful and honest. Under 17 U.S.C. § 512(f), anyone who knowingly makes a false claim in a takedown notice or a counter notice may be liable for damages, including costs and attorney fees. If you are unsure whether material infringes your rights, consider speaking with a lawyer first.
Repeat Infringers
Proportion Calculator does not host content uploaded by visitors. However, if we ever accept outside contributions, we will remove access for anyone who repeatedly infringes copyright.
Using Our Content
Our own guides, calculator code and worksheets are protected by copyright too. You may link to any page and quote short parts with credit, as our Terms and Conditions explain. If you want to use more, just ask us first at proportioncalculator.marketing@gmail.com.