This is a bit of a riff on the Yasso Marathon Predictor, and although it might or might not work as a predictor for you – it did for me. Keep in mind that with predictor workouts they are only an indicator and all of the other areas of your training have to be on board. In theory, someone without specifically half training could run fast 800m repeats and it doesn’t mean they can replicate that for a half marathon. But if you’ve been half marathon training and everything has been going well, this one can help you pin-point where your pacing might be for the day.

So this is 6 x 800m Intervals with 400m Recoveries between each.
The key to any good quality session is warm up. And I mean really warm up. So that is usually 2-3km of easy running and about 4 strides of 100m accelerations with about 1-2 minutes of walking between each to wake up your legs and get them ready for what they are about to do.
I ran my 800m in an average time of 3:32. So for my predictor I look at that in hours and minutes instead of minutes and seconds. so 3 hours and 32 minutes. I then take off 10 minutes (3 hours, 22 minutes) and I then divide by 2. Which gives me 1 Hour and 41 minutes for my half prediction. (I actually ran 1:40:40). Those calculations are just because it’s converting it from marathon time to half marathon time – but here’s a handy table so you don’t have to do the math
2:40 800m Intervals (3:20 min/km pace): 1 Hour 15 Minute Half
2:50 800m Intervals (3:32 min/km pace): 1 Hour 20 Minute Half
3:00 800m Intervals (3:45 min/km pace): 1 Hour 25 Minute Half
3:10 800m Intervals (3:57 min/km pace): 1 Hour 30 Minute Half
3:20 800m Intervals (4:09 min/km pace): 1 Hour 35 Minute Half
3:30 800m Intervals (4:22 min/km pace): 1 Hour 40 Minute Half
3:40 800m Intervals (4:35 min/km pace): 1 Hour 45 Minute Half
3:50 800m Intervals (4:47 min/km pace): 1 hour 50 Minute Half
4:00 800m Intervals (5:00 min/km pace): 1 Hour 55 Minute Half
4:10 800m Intervals (5:12 min/km pace): 2 Hour Half
4:20 800m Intervals (5:24 min/km pace): 2 Hour 5 Minute Half
4:30 800m Intervals (5:37 min/km pace): 2 Hour 10 Minute Half
4:40 800m Intervals (5:50 min/km pace): 2 Hour 15 Minute Half
4:50 800m Intervals (6:02 min/km pace): 2 Hour 20 Minute Half
5:00 800m Intervals (6:15 min/km pace): 2 Hour 25 Minute Half
5:10 800m Intervals (6:27 min/km pace): 2 Hour 30 Minute Half
5:20 800m Intervals (6:39 min/km pace): 2 Hour 35 Minute Half
5:30 800m Intervals (6:52 min/km pace): 2 Hour 40 Minute Half
5:40 800m Intervals (7:04 min/km pace): 2 Hour 45 Minute Half
5:50 800m Intervals (7:17 min/km pace): 2 Hour 50 Minute Half
6:00 800m Intervals (7:30 min/km pace): 2 Hour 55 Minute Half