Pre-workout most likely will break your fast, but if you read the nutrition facts carefully, you can possibly find a calorie free one which will not break your fast.

Can I workout before breaking intermittent fasting?

Make sure your workout is at least an hour before you plan on breaking your fast to ensure you get the full benefits of your workout. Like I mentioned earlier, the longer you wait, the more benefits you will get. I typically try to wait 2 hours after my workout before breaking my fast.

Will 5 calories break a fast?

Strictly speaking, any amount of calories will break a fast. If a person follows a strict fasting schedule, they should avoid any food or drinks containing calories. Those following a modified fasting diet can often eat up to 25% of their daily calorie needs while fasting.