McMillan calculator times

Accurate ?

1 to 20 of 38 messages
05/05/2013 at 17:22

I've been running again for about 2 months now since being out for a year with 3 consecutive fractures.  I've got my confidence back again which was the hardest thing and am now able to run 8k, I'm building up slower this time. To give me something to aim for I have entered my first marathon next year. It was during my first half mara last year that I fractured my fibula. When training for my half, my 5k PB came down by a minute. I put that PB into the McMillan calculator and was quite surprised by the marathon time it gave me. I just wondered how achievable/realistic this is ? I appreciate that a sensible training plan and remaining injury free are key but should I target this time ? I noticed also that the predicted time for my half was 10 mins quicker than I was aiming for and apart from breaking my leg I was feeling pretty good and considering upping my pace. in the end it was all I could do just to finish !


05/05/2013 at 17:31

I wouldn't be comparing my 5k time to a marathon just yet. What pace were you running your HM at when you became injured? This may be a better guide until you manage to get a few more racing miles under your belt.

05/05/2013 at 17:41

Absolutely. It's a year away and I have a lot to do before then. I haven't raced a 5k yet but reckon I'm at least 5 mins off my PB time. I was aiming for 1 hour 45 for my HM and was running at about 7 45 m/m at the 7 mile mark and feeling quite good. it was about a half mile later that it went wrong. 


05/05/2013 at 17:44

The marathon times it gives are wildly optimistic.  Add another five to ten minutes at least.

Edited: 05/05/2013 at 17:44
05/05/2013 at 17:49

Thanks. If I got within 10 minutes of it I'd still be extremly happy. 

05/05/2013 at 18:12

McMillan was actually strangely accurate for my half to full marathon conversion (give or take 10 secs), but there are loads of different factors:

- HM time is a better comparison because closer in distance.
- I'm a woman (Fetch calculator reckons that makes a difference).
- I'm better at long distance than speed, my 5k is (comparatively) pretty crap. This might be why women tend to convert their mara times better than men?
- I did about twice the mileage for marathon training as I would for a half.

So what I think is that you can only use the various calculators alongside what you know about yourself and what kind of runner you are (better at speed/endurance, how much time you're willing/able to spend training, etc.)

Edited: 05/05/2013 at 18:12
05/05/2013 at 18:20

Interestingly the Fetch calculator seems more accurate than the others I have seen.

05/05/2013 at 19:16

i know one chap whose 5k and marathon match on the predictor!

I find that incredible, as I find that from longer distance down, McMillan throws me some outrageous targets.

Whereas 10miler to half it's pretty spot on.

I may just be better at long distance, which I don't like the idea of, as those types get sucked into marathons

05/05/2013 at 19:19

Stevie, couldn't you be tempted to just do ONE, just to see...?

05/05/2013 at 19:47

Just remember the calculator caveat:  time is valid if you've trained for the distance.

I've comfortably beaten my Macmillan predicted times for everything up to marathon. But not marathon, despite some serious training.

05/05/2013 at 19:58

Litty, I covered 26.2miles over 4hours once, which included a 30min drinks and ice lolly break!

Was a miserable day, boiling hot, and just 2 of us running the route as part of a club "chairman's challenge", which used to get about 20-30people involved, but was dying on it's ass by the end.

We were meant to do 11miles out and the same back, got the wrong route, and ended up doing the extra 4.

Despite feeling utterly wiped out, we were bloody minded enough to make up the extra 0.2miles

05/05/2013 at 19:59
Ben Sales wrote (see)

Just remember the calculator caveat:  time is valid if you've trained for the distance.

I've comfortably beaten my Macmillan predicted times for everything up to marathon. But not marathon, despite some serious training.

out of interest Ben, what are your pbs...

have you tried going down the scale? ie from your half marathon pb, have you beaten what it says for 10k and 5k?

05/05/2013 at 20:02

Beating my McMillan 5k and 10k predictions are next on my list. 

Shit, just realised I'd better not try to beat my half marathon PB till I've done those or it'll get harder.

05/05/2013 at 20:27

i can't come close to my 10k off my half time (which was a big pb in Feb)...and can't get to my 5k off my 10k (either the Feb, or March pbs)...and can't get to my 3k off my 5k.

there's some science in this i'm sure

05/05/2013 at 21:07

ooh, just had a look and my 8k XC time from Jan is pretty close from my marathon time. Maybe I will turn out to be the one example of McMillan calculator accuracy!

05/05/2013 at 21:20

Talking of Fetch, is it possible to upload my runs from garmin connect?  The Fetch seems to imply that this is possible but doesn't seem to work in real like.

05/05/2013 at 21:24

SR, let me know if you manage it, as I want to use Fetch for the analytical tools but haven't been bothered yet rummaging around for details of exactly what gets uploaded and displayed.

05/05/2013 at 21:33

My 5k, 10k and HM and all pretty much in line. Mara is 20-25 mins too slow on McMillan. That fetch calculator seems better and is only 3.5 mins off. 

05/05/2013 at 22:06

Lit,  tried again, still doesn't work.



05/05/2013 at 22:27

I found the Fetch predictor to be more accurate for my marathon time. If I plug in my half time, it gets my marathon time right within 30 seconds. Interesting that it gives different half to marathon conversions depending on gender.

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