More accurate marathon time calculator

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davemunger
davemunger Posts: 1,139 Member
in Fitness and Exercise
This is pretty cool:

Slate's Marathon Time Predictor

It definitely seems to be more accurate for me -- based on my 5k time, Runner's World says I should be able to run a 3:00 marathon. This calculator gives 3:15, and my actual PR in a marathon is 3:22.

From the article:
A typical runner in our study with a 1:45 half-marathon time (8 minutes per mile) had a marathon time of 3:53:10 (that’s 8:54 per mile). Yet the Runner's World calculator predicts that this runner will finish in 3:38:55—15 minutes faster than the actual result. That’s an “absolutely massive” error, says Vickers. If this runner paced himself according to the Riegel prediction, he would start the race at a pace that was more than 30 seconds per mile too fast. “No wonder so many runners blow up and limp to the finish,” Vickers says.
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Replies

  • JustWant2Run
    JustWant2Run Posts: 286 Member
    edited October 2014
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    Interesting.

    Based on my 1:45 half pr, raced 4 weeks before my first full, I would have run a 3:54 marathon. My first marathon was a 3:49.

    That half is still my pr, and I ran a 3:44 10 days ago...

    So this actually predicts I would be slower than what I am. Maybe I need to race a half? lol

    (PS: my 5K pr is predicting a 3:56 full...)
  • davemunger
    davemunger Posts: 1,139 Member
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    Interesting. I'm a little surprised it doesn't ask your gender, because I have found that the traditional calculators are more accurate for women than men.
  • DavidMartinez2
    DavidMartinez2 Posts: 840 Member
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    I would suggest using races from this training cycle.
  • JustWant2Run
    JustWant2Run Posts: 286 Member
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    davemunger wrote: »
    Interesting. I'm a little surprised it doesn't ask your gender, because I have found that the traditional calculators are more accurate for women than men.

    With my 1:45 half, McMillan is predicting a 3:40 marathon.

    It's the first time I hear about female vs male accuracy. Interesting.
  • JustWant2Run
    JustWant2Run Posts: 286 Member
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    DavidMartinez2 wrote: »
    I would suggest using races from this training cycle.

    Then it would predict a 3:55 marathon. I ran a 3:44.

    Maybe this prove that I need to work on shorter distances. :s
  • glevinso
    glevinso Posts: 1,895 Member
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    Useless. It is telling me I am predicted to run slower than my PR marathon based on significantly faster half-marathon times than I have had in the past and many more miles-per-week.
  • saskie78
    saskie78 Posts: 237 Member
    edited October 2014
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    This also has me slower than my most recent marathon by 20 minutes. Runners world prediction is off by just 3 minutes.
  • ryanwood935
    ryanwood935 Posts: 245 Member
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    I fall right in the middle of the two. I haven't been in marathon shape for years, but back in the day, Yasso 800s was very accurate for me.
  • SonicDeathMonkey80
    SonicDeathMonkey80 Posts: 4,489 Member
    edited October 2014
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    I used a 5K and HM, both current PRs in the current cycle. It forecasted a 3:34, and my marathon PR from this cycle is 3:30. I'd rather have the more conservative time than the 3:1X that McMillan/RW/Daniels tells me. I'm not a fan of exploding on a marathon.

    *ETA: while useless after your first marathon, I'd much rather see people use this to get a feel for approximately where they'll finish. And that's if they absolutely must time their first - with few exceptions, most should train to finish rather than dump expectations on themselves.
  • CodeMonkey78
    CodeMonkey78 Posts: 320 Member
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    Odd. This calculator predicts a 3:40 marathon while McMillan predicts 3:38:30 (based from a 5k raced last weekend). I know I could have raced this at least a minute faster if my back would have cooperated, but it is what it is.

    I am curious to know how they use the mileage based scaling in their predictive time. Weekly averages of 29 & 35 mpw (from the article) seem really low for someone actually working to achieve their predicted marathon time.

    Just my $0.02.
  • litsy3
    litsy3 Posts: 783 Member
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    McMillan works pretty well for me.
  • SonicDeathMonkey80
    SonicDeathMonkey80 Posts: 4,489 Member
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    I think the bigger win for this is a first time marathoner, as in a "couch to marathon" person - not someone who has run multiple marathons, nor a comparable athlete who just started to run.
  • davemunger
    davemunger Posts: 1,139 Member
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    Training2BeFast wrote: »
    davemunger wrote: »
    Interesting. I'm a little surprised it doesn't ask your gender, because I have found that the traditional calculators are more accurate for women than men.

    With my 1:45 half, McMillan is predicting a 3:40 marathon.

    It's the first time I hear about female vs male accuracy. Interesting.

    Well, so far the responses here seem to bear that out.
  • litsy3
    litsy3 Posts: 783 Member
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    For gender difference (Riegel calculator adapted for some real-life stats), try this one:
    http://www.fetcheveryone.com/training-calculators-improvedriegel.php?hours=1&minutes=24&seconds=52&update=Update
  • hermann341
    hermann341 Posts: 443 Member
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    I'm a fan of these calculators:

    http://www.runningforfitness.org/calc/racepaces/rp
  • SonicDeathMonkey80
    SonicDeathMonkey80 Posts: 4,489 Member
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    hermann341 wrote: »
    I'm a fan of these calculators:

    http://www.runningforfitness.org/calc/racepaces/rp

    In my dreams lol

  • litsy3
    litsy3 Posts: 783 Member
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    I like the idea of the average prediction, but I think the inclusion of age grading skews the results, because age grading is based on the world record at a specific distance, not a comparison across distances. So it's not really a 'prediction' at all and isn't designed to do the same thing.
  • davemunger
    davemunger Posts: 1,139 Member
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    litsy3 wrote: »
    For gender difference (Riegel calculator adapted for some real-life stats), try this one:
    http://www.fetcheveryone.com/training-calculators-improvedriegel.php?hours=1&minutes=24&seconds=52&update=Update

    That's a nice one...definitely seems to capture the gender difference I've observed. It's still 10 minutes on the optimistic side for me though...
  • Carrieendar
    Carrieendar Posts: 493 Member
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    RW: 3:06 McMillan:3:08. This calculator: 3:14. We will see Sunday!!!
  • RunnerElizabeth
    RunnerElizabeth Posts: 1,091 Member
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    So i used my HM from 3 weeks ago on a bad foot (not a pr) and my 5k from last week, not a pr, but i did record my fastest mile ever in the race even though i ran with my jogging stroller. There is a 10 min difference between using this with my recent races vs. my pr's. So I've decided to go out at the pace this predicts based on the recent times and work my way down some if i feel lovely at mile 16. We'll see how it goes on Sunday.

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