Run a race, any race

A plan for your first parkrun, 10K or marathon, with calculators for pace, training and race day.

The plan, in 5 steps

  1. 1Start where you are
  2. 2Predict a realistic finish time
  3. 3Turn that time into a pace
  4. 4Keep easy runs easy
  5. 5Build up gradually

Step by step

Steps to race day

Work through these once now, then come back as you get fitter and your numbers change.

  1. Start where you are

    New to running? NHS Couch to 5K takes you from walking to running 5K over nine weeks, three runs a week. This tells you when you will graduate if you start this week.

    Open the couch to 5K finish date calculator

  2. Predict a realistic finish time

    Enter a recent race or time trial and the Riegel formula estimates your time over a different distance. It is a guide, not a promise, and it is kinder over shorter jumps.

    Open the race finish time calculator

  3. Turn that time into a pace

    Minutes per mile or per kilometre, whichever your watch speaks. Knowing your goal pace stops you setting off like a greyhound and finishing like a tortoise.

    Open the pace calculator

  4. Keep easy runs easy

    Most of your running should feel chatty. Heart rate zones give that feeling a number, which helps if you tend to push every run.

    Open the target heart rate calculator

  5. Build up gradually

    Adding distance slowly gives muscles, tendons and bones time to catch up. This shows what a gentle weekly increase looks like over a training block.

    Open the weekly mileage increase calculator

Pick your race

Which distance suits you?

5K

The friendliest start. Free, timed and weekly at parkrun, on Saturday mornings at 9am (9.30am in Scotland), and walking it is welcome.

10K and half

A good next step once 5K feels comfortable. Most people give a half marathon around 10 to 14 weeks of steady training.

Marathon

A big but very doable goal. Give yourself at least 16 weeks of training on top of being able to run for an hour, and plan a taper in the last two or three weeks.

How to train

The boring bits that work

  • Run easy most of the time. Being able to talk in full sentences is the test.
  • Add one harder session a week once you are comfortable: a few faster minutes, hills or a parkrun effort.
  • Increase your weekly distance slowly. The 10% rule is a rule of thumb rather than science, but going steady is good advice.
  • Have at least one rest day a week and sleep well. Fitness is built while you recover.
  • Add two short strength sessions a week. Squats, lunges and calf raises help keep injuries away.

For runs over about 90 minutes, practise eating something carby on the go, and drink to thirst. Drinking far more than you need can be as risky as too little.

Listen to your body

Niggles, pains and when to stop

Some stiffness after a run is normal. Pain that makes you change how you run, gets worse as you go, or is still there the next day is a sign to rest and get it looked at. A physio or your GP can help, and you can refer yourself to NHS physio in many areas.

Stop and call 999 if you get chest pain, a racing or irregular heartbeat, or feel faint while running. These are rare, but always worth taking seriously.

Questions

Common questions

How long does it take to train for a 5K?

If you are starting from scratch, NHS Couch to 5K takes nine weeks with three runs a week. Plenty of people repeat a week or two, and that is completely fine.

What is a good time for a first 5K?

Any time with a finish in it. Lots of first parkruns take between 30 and 40 minutes, and plenty take longer. Your first one is simply your personal best.

How accurate are finish time predictions?

They are best when the distances are close, so a 10K predicts a half better than a 5K predicts a marathon. They also assume you have trained for the longer distance, so treat them as a sensible starting target.

Should I run every day?

Not at first. Three runs a week with rest days in between is plenty for most beginners. More running can come later, built up slowly.

Do I need to see a GP before I start running?

Most people do not. It is worth a chat with your GP first if you have a heart or lung condition, have had chest pain, take medicine for blood pressure or have not been active for a long time.

Sources

Last checked 21 October 2026. Every calculator on this page links to its own sources too. More in Fitness and running.

Before you lace up

New to exercise, or got a heart, lung or joint condition? A quick word with your GP or practice nurse first is sensible. Stop and get help straight away for chest pain, fainting or a racing heartbeat.

Other goals

Got a different goal?