Kneading bread dough
It seems there is no reliable conversion formula - if you check the websites of mixer manufacturers, they go as low as 1/5 of the time (KitchenAid) or suggest machine-kneading for about 4/5 (Bosch). And I don’t think it’s just because the KitchenAid is so super fast.

The good thing is that the lack of a formula forces you to learn how to recognize a well-kneaded dough. I let you in on a little secret here: if a recipe gives a kneading time, it’s simply an estimation or approximation of how long a user may have to knead to reach a certain stage. Individual technique and even working speed varies so much, that a value like ten minutes is just ballpark number.

When you prepare a bread dough, your goal is to create a gluten structure that will trap the gasses and give you the desired crumb texture. There are two main methods:


One uses mechanical kneading for a “long” time and you can recognize the desired results when the dough becomes very homogeneous, smooth and so elastic that it can be stretched to almost translucent thinness (-> window pane test). That’s what a recipe that calls for ten minutes of kneading is aiming for, so check for that stage when using a stand mixer.
The other approach doesn’t knead, but just mixes the ingredients and let the gluten develop over time (-> no-knead bread, stretch-and-fold). But that’s a totally different concept that needs a lot more time. Not the method of your recipe, though. 


So in short, if you really need a number (e.g. if you want to set a timer and walk away), instead of finding a generic conversion formula, you could measure how long it takes for your recipe and your machine to get a well-kneaded dough and then use that value in the future.