10:30 goal- workout at 8:15 pace???

10 minute miles are 6 minute kilometres. Is something set incorrectly?

8:15 intervals are still good training for a longer 10 mile run. I regularly do intervals at an equivalent pace.

I was wrong. Just fixed my post. Still don’t know why it thinks I can go that fast. I didn’t want it to dumb down my training, so I put in my real race goal. The race is in February. 

I hate to say this, but if your 10 mile race goal is 10:00/mile, and you are only able to run 9:30/mile for 1 mile intervals, you might not reach your goal.

Also, if your 5k race pace is 9:25/mile, I think you should be able to run 1 mile reps faster than 9:30.

Anyway all of that was just my intuition (for reference I've raced a 1:34 half marathon, and rn I'm probably in shape to race 1:39 or 1:40 - I've also run with a lot of people who are much faster or much slower than me).

I plugged your goal and recent 5k time in https://www.mcmillanrunning.com/ 

The good news is that your 5k result lines up fairly close to your 10 mile race goal. The equivalent 5k race pace to your goal is 28:49 (9:16/mile), which is "close enough" to your recent 29:15 (9:25/mile) result. 

But the same calc recommends the following training paces for 1 mile reps:

- for "endurance monsters": 9:08 - 9:23

- for "speedsters": 8:39 - 9:08

This does indicate that Garmin's 8:15 target is very aggressive. The discrepancy could be due to the fact that mcmillan's training paces are based on your recent race result and not your goal. If I lie to the calc and say that you recently raced a 10 miler at 10:00/mile, then it does suggest 8:32 - 9:01 for the "speedster" pace (which is still slower than 8:15)