Here are some possible English equivalents, depending on the desired meaning or sound:
Similar in sound:
* Joest
* Yost (this is already English, though may not be as common)
Similar in meaning:
* Joseph (meaning "God will increase")
* Justin (meaning "just" or "righteous")
* Joachim (meaning "God has prepared")
Ultimately, the best "English equivalent" would depend on the context and the specific meaning you're looking for. If you have more information about the name's origin or the person's family history, that could help narrow down the choices.