NOTE - the downloadable files sourced from OpenSSL.org only work with Linux!!! In order to install on Windows 10, you must with compile the binaries yourself OR find a compiled version already on the web. The instructions below will only talk about finding a website with a compiled version of OpenSSL.
The other answers used different sources than Cygwin, which is what I recommend, so I copied my steps here, since I recently needed to document how to work with it. In addition to providing a wealth of Windows utilities, Cygwin is well maintained. Additionally, Cygwin assists when needed to fix vulnerabilities by allowing you to easily update versions as needed. OpenSSL should be updated frequently! check out calculadoradeporcentagem