half marathon pace

This may seem like a daft question but this will be my first half and only my third race and I dont know how fast I can/should run over 13 miles.

My time for 6 miles is around 45mins and I can run at 7:30 ok. If I go on a longer run I obviously run within myself. My longest run to date is 10 miles in 1hr 25. The complicating factor is the first half is downhill and the return in uphill.

I want to run the best time I can but not failing to finish whilst trying. The doubts are creeping in and I have not got a plan yet to tackle them. Is there a formula?



  • No formula that I can think of. Even paced running is the best way to go.

    Your 10 mile pace is about 8:30 minute miles and your 10km pace is 7:30 m/m. I think you've certainly go the training to finish but the pacing is crucial.

    Unless the hills you talk about are pretty constant and severe, I'd go for an even pace run at about 8 min/mile. On the downhill bit, you could go faster without expending excess energy - on the uphill parts, you will naturally slow down a bit cos its uphill. It is the perceived effort you need to keep constant, i think.

    best of luck

    the bat
  • If you try the following link it is excellent for predicting race times from other performances:

    http://www.mcmillanrunning.com/Running University/Article 1/calculator3.htm

    For example if you can run 45 minutes for 10k then your predicted time for a half marathon is about 1:40.

    Remember though that predictors are only an average and in the early stages of your racing career you should err on the side of caution to make sure you finish comfortably. So aim for 1:45 - 1:50 and be pleased if you beat that.
  • I seem to remember that www.onrunning.com has a race time predictor. You put in a known race time, then it calculates what you can do at other race distances.
  • Based on these calculations, you could perform at these times over these distances. (See this

    5K 0:24:35
    5M 0:40:35
    10K 0:51:29
    10M 1:25:00
    Half Marathon 1:54:10
    Marathon 3:59:07

  • nb - i used your 10M time as a guide
  • Cat in the Hat, You may be interested to know my PB for a 10K is 45.39 so very similar to yours.
    Well I was facing the same dilemma (I can't spell that word) last weekend in my first Half in Inverness.

    Inverness is a flat course so I didn't have the same "downhill start" problem so I decided to blast it early on and tyr and hang on as long as I could. Well I made half way just inside 50 minutes and 10 miles in 1 hour 19 then died a bit and came home in just over 1 hour 44 minutes.

    Assuming our fitness level is similar then I'd suggest you set out at 7.45 mile pace if you can as you're bound to slow on the return hill. So aim for 1.50 due to the hill then you'll be chuffed if you do better.

    Best of luck

  • Thanks everyone for the valuable advice. I completed the Ironbridge Half Marathon yesterday. It was hot and my condition was not improved by twisting my ankle (again) at 2 miles. There were too many runners running abreast and I stepped half off the side of the track - OUCH! The first 4 miles were bang on 8:30 pace and I was really enjoying it, knowing that I had lots left.

    I was able to pick up the pace in the last mile and finnished with a time of 1:50:04. Which works out at 8:24 per mile. I am happy with my time thanks to you all!

    I recommend the Ironbridge Half. Lots of off road and through the Shropshire countryside - All those I spoke to on the way round said that they rate it as one of the best.

    (The Cat in The Ankle Support)
  • well done - good time.
  • ijust done my first race i thoght it waS 10 K BUT WHEN i arrived i found out it was 10 miles up hill,i had a heart attact before i started but i did do all that up hill course i came last with the parapidics along side me, as i was the last one ,very sad but my excuse is i have beast cancer and my pretend stick on boob did not stick on and was slinding everywhere,can anybody help as when i do the southend 1/2 i would really like not to come last
  • Hi Jayne,

    Take heart. 10 miles is very, very different from 10K so it's not at all surprising that you found it difficult. But you finished!

    For your first race that's amazing - many beginners don't attempt 10 miles, so generally you would have been running with a much more experienced crowd.

    This is not the case with a 1/2 marathon which is a much more popular distance with all sorts of runners, beginners, shapes and sizes attempting it.

    So here's some tips and thoughts.

    1. You only need to be able to run another 3 and a bit miles than what you've achieved already.

    2. There will be many, many more beginners at a 1/2 marathon

    3. Train until your socks come off.

    4. Even if you do come last, so what. Swallow your pride. You'll have run a half-marathon and with your pretend stick on boob that's one hell of an achievement.

    Hope this helps!
  • Jayne,
    You've probably already done this, but check the race website:


    It give the results from 2003. You'd expect the same kind of entrance for 2004.

    In 2003 there were 550 or so people and last place was a dead heat (so there really wasn't a last place) in around 3:00 hours.

    So I echo 3TL. If you think you can beat 3 hours you are unlikely to come last. If you can beat 2:45 - you would beat me and I don't care ! If you can't beat 3 hours - who cares anyway. The way I look at it - wherever we come we beat about 8 million people in the South East who can't get off their arses to run at all.

    You have 2+ weeks to go. Some good runs in the next week and a steady and sensible taper to the race and you'll be fine. Just enjoy it.

    Good luck - and let us know how your training and race go.

  • Hi Experienced Runners,

    I have signed up for my first half this weekend, but I am not quite sure
    how I should pace myself. I did the Prince's Trust 10K at Legoland at 50
    min. My long run is a 20K which I do in 2:30 hour at 75% of max puls rate.
    I should be able to do better than that. However, what should I aim for at
    my first half? Should I run with a specific puls rate or just run...!! Can
    anyone give me a clue?

  • Hi Great Dane,

    You've got quite a big difference between your pace for the 10K (5min/k) and your 20K (7.5min/k).

    Pace yourself at the slower rate for the first 6/7 miles of the half, and if you're feeling good try and increase it by 10-15s per mile for the last 6/7. (or more if you're feeling speedy)

    This way you will still get under 2:30, but I suspect given your 10K result and ignoring your 20K result as an anomoly you can probably do much better than this and will end up under 2:15.
  • Thanks 3TL,

    I will take (not too) slow in the beginng and gradually build up the pace. My end goal is the London marathon so this first half should be a positive experience.

  • I'm doing the Tewks Half marathon this Sunday. My first since 1989. I'm aiming at 10mins per mile but my usual pace is best part of a minute faster. It's a flat course apart from one incline going over the motorway at mile 9-10. (does that count as a hill. When should I pick up the pace?
  • Hi David

    My pace is about 9min miles (just sub 2hours).

    I always aim for negative splits - the 2nd half of the race faster than the 1st. The first 2 miles are for me to get into the flow of things and to see how I feel on the day; then I run a steady pace for the next 6 or 7 miles, with mile times fairly consistent. If I get to 8 or 9 miles and things are still going well then I can think 'only 4 to go!' and then I start to pick things up through 10, 11 and 12.

    I really like the -ve split way, as I usually start near the back but benefit from catching up and overtaking more people than overtake me during the race - it helps me psychologically.

    You can only experiment to find what's best for you but most runners would advise not to start too quickly. Enjoy the race - may it be the inspiration to enter more!

  • Hi All,

     This may come as a shock to you but I would not worry about paceing yourself for about the first 3 miles of this run, unless you are near the front of the pack, as It gets quite crowded and their are a lot of run/walkers that insist on starting as close to the front as possible, and they will get in your way. (been there done it)

    Anyway good luck on your race times and keep us informed.

  • I'm 48, over weight and on the third week of my 12 week half marathon training program. I ran my first 5 miles yesterday in and hour....will everyone else have gone home by the time I finish?! Are my times likely to improve by week 12? And WHY after 3 weeks of running 4-5 times a week have I lost NO WEIGHT?! HELP!
  • First of all - well done for starting and for running your first 5 miles!

    Nope, there will still be lots of others around you I'm sure. Your fitness will improve over the next few weeks and the taper will certainly help you to feel strong on the day.

    Yes your times are likely to improve - you're only training at the moment, 9 weeks to go yet! Your long runs SHOULD be slower than you want the run the half marathon anyway, don't forget that you're also running in the week and have tired legs.

    Perhaps you're consuming more calories because you're running? Common mistake is to eat more or feel like you deserve a treat because you've been running or working out. Yes you're body does need more but I recommend that you find a calorie intake calculator online and follow that. My Fitness Pal app is pretty good for tracking what you've eaten and burnt off

  • The key to weight loss is 80% diet and 20% exercise. Exercise is not the green light to over eat. Refine your diet and you should see improved results in terms of your weight loss, fitness and running performances.

    Your half marathon pace is usually around 30 seconds slower than your 10k pace. Your HM pace is usually 30 seconds quicker than your Marathon pace. For example if your 10k pace is 7 minute miles, i.e. around 43 minutes, your HM pace should be around 7 min 30 second miles, ie around 95 minute Half. Marathon pace would be 8 minute mile pace, ie around a 3 hour 30 minute Marathon.


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