The RW Race-Time Predictor



  • Absolutely spot diddly-on for projecting best 10k time from best half-marathon time.....actually two seconds out.
  • Yup, not bad! I did a half-marathon yesterday, a minute quicker than my predicted time from a recent 10K. Doing Chicago Marathon and was hoping for sub 4.30, and its predicting me a 4hrs 10min..... Fingers crossed! YIPPEE!!!
  • Well I've not even entered my first race yet, but I've covered a 10k route in 41.35, which predicts a marathon of 3hrs 11mins - and it's still seven months to FLM, my first one.

    So chances are, I'll aim for sub-3, then hit the wall and crawl over the line on Monday morning. Heh!

    (I'll put my Nike 10k official time up there in 3 wks time and see what it says...)
  • 3 weeks ago I did 1.38.10 Half marathon - predicted time given for Marathon 3.24.40.
    Did Anglesey Marathon at the weekend in 3.47.11 it was a flat half and then quite a tough undulating full marathon, rarely do you get similar circumstances (weather, surface, undulations, preparations) for the 2 distances your trying to compare, so don't rely on it for an accurate guide.
  • I've just ran a 10km race in Hong Kong in 34.38. The course was slightly undulating and the temperature was 24c with humidity of 91%.I'll be doing a flat marathon in Japan in cool weather in two weeks time with a sub 2.40 target. I'm looking for a race calculator that takes into account the nature of the course and humidity, rather than just raw times. Any references welcomed, particularly if they kick out a sub 2.40 with this data!
  • The race predictor does not work for me. I did a 10k in 44min and a month later did a marathon in 4hr 30min. I put in the required training mileage for the marathon but have struggled in training as well as on marathon day upon hitting 24-25km. I don't know what I am doing wrong.
  • Saab - It's a fairly simple explanantion, I'm afraid (having used it several times this year). Marathons are bloody hard work. The body is designed for a max running distance of around 20miles (accoring to one of the guys I run with who's a GP and REALLY into his sports science), so you'll usually notice a big difference. Expecially if it's your first marathon, because whilst you've done enought raining to do the course well on the day (external factors aside, like weather & terrain), the body needs YEARS to build the sort of stamina to keep a 10K pace going for a marathon.
    The trick? Don't be downheartened! Keep up the training and remember that unless you're out to win it, the only person you've got to beat is yourself, so you've got times to keep aiming for and beating.
    If its any consolation, the predictor worked for me this year for 10K, 10M & half marathon. Did London marathon in april in 4 hrs 48 mins then found the predictor & used it for the other races. I did Windsor half in 2hrs 0 mins 27secs - it had predicted 2hrs 2 mins based on 10K time, did a 10M race about 30 seconds than predicted. See above - it predicted me 4hrs 10 for a marathon, and in Chicago I went through the half in 2hrs 1minute, but finished the entire thing in 4hrs 23mins. So, I walked a little at the end, but I enjoyed it!

    If you always seems to bottom out after 25K, is it your energy supplies? Are you taking on enough carbs before the race, and enough energy drinks/gels during it? Or, classic error, are you starting too fast? (done that, oh so very many times before).

    Set yourself some reasonably achievable goals for the new year, and just KEEP IT UP! Maybe try running with other people, a bit of cross-training maybe. You'll find most of what other info you need on this site..... I certainly have!
    Good luck for the next marathon, and have a Merry Christmas!
    emms x

  • There was a very long thread on this about a year ago with lots of 'science' based on peoples results. I think the conclusion was, as I remember, that if you were 20 mins 5k or less it almost certainly did but the slower you were the less accurate it was.

    My view is that it is probably only not accurate for people who have not done enough long runs.

    Last April my best time for a 10k was 46:12 and it reckoned I could do London in 3:32. I did 3:44 but actually deliberately held back in case I blew up so I reckon that might have been right.
  • Well my 10k is 35:58, and doing a half next week, it predicts 1:19:20, so we'll see how I go ;-)

  • i did a ten 10k in 52m28s last sunday and seven days later ran teignbridge ten mile in 1hr24m58s
  • which was two minutes FASTER than predicted
  • Come 22 Apr I'll be ecstatic if it is anywhere near accurate. My half time today gives me a mara target of 3.50 which would give me a reasonable cushion for my sub-4 target and, most definitely, a huge pb (currently 4.21).
  • It is spot on with the 5K prediction for me (34:04 predicted; 33:52 best real time) but nearly 2 minutes off the 10K time (1:11:01 predicted; 1:09:09 best real time effort).
  • PB was 5.20 in 2003. Half marathon time is now 2.15. Predicted time 4.41.. Seems a bit fast to me but who this space.
  • Accurate to within 20 secs for 5k/10k but predicted a rather optimistic 2.44 for a marathon based on a 1.19 1/2. Reality is 10-15 minutes slower, maybe I need to do some longer training runs.
  • Unless my maths is wrong, looks like the equation used in your tool is

    T2 = T1*(D2/D1)*1.042 (not 1.06)
  • well I have a log for the last 9 months based on runs of between 3.5 miles and 21 miles, each predicting a marathon time.

    in general I find the prediction increases the longer the run is but maybe that just suggests my endurance isn't what it should be. the range goes from 3:57 through to 5:02 (over an hour's variation!) with the majority of predictions in the 4:30-4:45 range which suggests to me that my best is probably somewhere in that range.
  • I cannot achieve any accuracy with this predictor. I have run 10 marathons and 2 x 50k races in the last 5 years always round 3:35+ for marathon and 4:30+ for the 50k until this spring when i barely broke 4 hrs for two consecutive marathons though I trained and prepared as for prior races. However, recent repeatable times 19:30m for 5k and 41 min for 10k suggest should be much better for marathon and in last few days ago did 25:56 over an accurate 4.2 mile flat race which suggests (according to predictor) something like a 3:00 marathon.....all i have done since spring is concentrate on shorter distances and hill races doing a race on average every 9 days since mid april. The fascinating thing is that getting faster over shorter distances is theoretically making me a much faster marathoner which of course is complete nonsense unless i put in half dozen hard 20 milers in 12 weeks before marathon. To distil the infinite variables of human physiologies, environmental conditions, training programmes, etc etc etc into one line of a rather unsophisticated piece of arithmetic stretches the imagination somewhat......or does it?
  • 7th October: 10K in 36:15

    10th October: 5K in 17:04

    prediction was 17:23 based on 10k time

    21st October: Half Marathon

    prediction on 5K time - 1:18:25

    prediction on 10K time - 1:19:54

    My Half PB is 1:25 and will be aiming to run 6 minute miles which would give me a time of 1:18:36. I think the calculator is pretty accurate but is clearly dependant on the training you have done, how recent your race time is and your tactics for the race. I ran the 10K conservatively to ensure my target time was achieved. I guess I could have pushed it harder.

    Will see how it goes on Sunday

  • I'm amazed how well this works - I fed in my half-marathon time from March, and it got my 5 mile time spot-on, and my 10 mile time only 20 seconds too long. A bit worse on the marathon (about 18 minutes inside my PB), but I'm sure that's down to lack of training. It was even pretty good on 1 and 2 mile track times - my real times were 10 seconds or so slower, but I know I wasn't fully fit when I ran them.
  • The real difficulties with these tools relate to marathon time predictions, especially if you are trying to predict up from a race distance that's more than 50% shorter. Most people under prepare, that's true. They also run fewer marathons than shorter races, because of the ease of recovery. Therefore the pb at the short race is when you are at peak with conditions perfect, yet the day of your (annual?) marathon could be anything but. The result being that the marathon prediction is likely to be the BEST that you could expect, and the likely spread being quite wide beneath that.

    I fear also that the formula is probably in need of a minor age factor too, as several of us vet types have found that we need to be able to run a faster HM to get to a given marathon time. And that's taking the training variation into account.

  • eg

    for a 3 hour marathon, it suggests 1:26:20 is enough. Tosh.

    Greg Macmillan reckons a 1:25 is needed, and he's a bit hopeful too. Maybe OK for a 23 year old, but it can be done off that time.

    I reckon that I need to have clocked 1:23, AND put 8 runs over 20 miles in, AND that a few of those need to be fairly quick. Doing 60mpw plus is also pretty much an essential.

  • I know someone who is hoping to run a sub 3 off an undulating 1:24 half. For me, esp as a larger bloke, I find the longer the race the more my fade so it works for 5k/10k but not too well for maras.

    There was a thread on this a while back where people collated their experiences and it turned out from what I can recall that the faster runner you were, the more likely it was to be right.

  • 21st October: Half Marathon

    prediction on 5K time - 1:18:25

    prediction on 10K time - 1:19:54

     Outcome: 1:19:00

    I'm now hoping I can convert this into a sub 2:45 marathon at FLM 08. As Blisters has said, it now comes down to specific maratho prep. The 1:19 indicates I have the pace, now I have to add the endurance to prove this calculator correct (It predicts about 2:44:45 I think)

  • PhilPubPhilPub ✭✭✭
    SP - well done on the HM. We've got very similar racing stats; going into HM last week I had fairly recent PBs of 17:20 for 5k and 36:01 for 10k. Target for HM was 1:20 and I paced myself round for a 1:19:39.

    FWIW I think Macmillan is a little bit closer to the mark than RW, which I find quite bullish in its estimates from shorter races. Still, one way or another I hope you're right about just needing to add endurance to your speed for a quick marathon time next year. I'm doing Paris (one week before FLM) and whilst I won't set a definite target until much nearer the time, the idea of 2:45 sounds fantastic!
  • Its not accurate for me yet. I can currently run 5k in 23:08 which predicts 48:00 ish time for 10k. But although I'm improving, I haven't quite broken the 50 min barrier and my pb stands at 50:49.

    However, I'm still relatively new to running, carrying too much weight and my endurance isn't what it could be. So in a way, the race time predictor's value is in showing me what I could be capable of with more training. 

  • Hiya, used this for my half, very accurate, really pleased. It suggests i can do FLM in under 4hrs, if i do that it would be amazing for me as a first timer.
  • Thought I'd ressurect the thread with my experience.....

    I'm female, 27 years old
    Decided in Jan to run Edin Marathon and Half as Perparation. Maybe a bit daft - started running again after 3 years (and previous was half hearted) in July, ran 10k in Sept and only one two other 10k traing runs. I'd never ran over 10k until January this year.

    Took over 6 minutes of 10km in Feb -
    50:42 at Grangemouth on nice flat course,

    From 10k Predicted 1:23:46 for 10 miles. March 2nd ran V Hilly Lasswade 10miles in 1:27:56 (I haven't trained on hills so guessed this prolly not far out)

    From 10k - Half Marathon predicted 1:51:45 - thought this was optimistic as prolly not enough consistent mileage in my legs. Fast (if somewhat nasty windy) Edinburgh Half course today - 1:51:53 (or thereabouts).

    From 13.1 miles time of 1:51:53 - 26.2 miles prediction 3:53:16. I know the predictions only 'work' if you train 'properly' for the event you are doing so I'll do my best to stick with the training and get my 20 miles runs in then update on this thread.

  • Moreorless right for 10k.  I'm an older runner (64) who started late(57) with no previous running experience.  Can't get the time to translate to marathon distance from half - half marathon always round about 2.45 for the half but constantly come in at between 6.08 - 15 for marathon - lose endurance so I suppose I should train more on the longer distances and start off a bit more quickly in the 10k- find these calculations very useful though - keeps me realistic!
  • My 10k and Half marathon times are preety good, 10k says 51m, i took 50.09, Half 1.51, i took 1.53, im hoping to do the FLM in 4.30 and this says 3.55, so bring it on!
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