Running paces
The following table comes from Slowtwitch.

I took the dogs for a walk this morning and got home about 8:30am. I then had this cunning idea about doing the Basingstoke Park Run. Trouble is it starts at 9:00am. So 30 mins to find some kit, get 4 miles to town and do a warm up. It was a bit of a rush but I did it.
I did this 5k before in November 2008 in 20 minutes 30 seconds. I was disappointed with that time but it is what I did.
Today, I wanted sub-20 mins. I have been training well for the last four months and so I felt I should have improved.
But I didn’t know who to run with and I didn’t want to run too fast to start with. So I went reasonably quick but not all out. There was a bloke who tried to overtake me about 0.5k in but I sped up a fraction. Then he tried again about 1.8k so I asked him what time he normally runs. He said twenty-and-a-half. So I knew I had to beat him. The first 2k were done in something like 7:50 but I felt I had a lot more in me. So I pushed the pace up quite a bit until it started hurting. The next 2k got me about a 100m lead over the guy I spoke to. By this stage I had also caught up with someone who was 80m ahead of me at the half-way point. I got to within 5m of someone else but kept thinking that I wanted to ease off the hurting. I think I probably did in that I stopped gaining on the bloke in front and didn’t do a sprint for the line, so he beat me by about 10m.
By my watch, I think I finished in around 19:38. The results aren’t up yet but as the organiser has probably only just got home!
That gives me a VDOT of 50. It also predicts a half-marathon time of 1:31.
So, all in all, a good start to the day.