Sentence examples for have to run from inspiring English sources

"have to run" is correct and can be used in written English.
You can use it when you need to express the idea that you have something (usually an important task) that you need to do, and that you need to do it quickly (e.g. time is running out, you have an appointment to make, etc.). For example: "I'm sorry I need to end the conversation now, I have to run to my meeting".