How far should I be able to run?
There's no universal distance you "should" be able to run. It depends on how many weeks of consistent running you've actually put in: your training age, not your calendar age or anyone else's mileage. The clearest verified anchor is the NHS's Couch to 5K programme, which takes a complete beginner from 60-second running intervals in week 1 to 30 minutes of continuous running by week 9, roughly a 5K for many people at a beginner pace. Past that point, how far is comfortable is a function of consistent weeks logged, not a number everyone should hit.
"How far should I be able to run" almost always gets answered with someone else's number: a marathoner's weekly mileage, a colleague's parkrun time, a training plan built for a different runner. None of that is useful without knowing one thing: how long has the person asking actually been running, consistently, without long gaps? That's the honest starting point, and it's the one below.
What Couch to 5K actually prescribes, week by week
The most widely used, publicly documented beginner running structure is the NHS's Couch to 5K running plan, a free nine-week programme built specifically to take someone from no running background to continuous running. It progresses by time, not distance, and the week-by-week structure is public:
| Week | What's prescribed |
|---|---|
| Week 1 | Eight 60-second runs, each separated by a 90-second walk |
| Week 3 | Alternating running intervals of 1:30 and 3 minutes, with matching walk breaks |
| Week 5 (run 3) | First unbroken run: 20 minutes, no walk breaks |
| Week 7 | 25 minutes unbroken, all three runs that week |
| Week 9 | 30 minutes unbroken, the programme's finish line |
That 30-minute finish is why the programme is called Couch to 5K: at a typical beginner pace, 30 minutes lands in the neighborhood of 5 kilometers for many people. It isn't exact (pace varies enough between beginners that 30 minutes might be 4.5K for one person and 5.5K for another), which is the point of a time-based plan in the first place. If you're earlier than week 9, the honest target is the minutes on the schedule, not a distance in kilometers.
Building past 5K: how much distance to add
Once continuous running is established, two separate questions come up, and they're often conflated. One is how long any single run should be relative to the week's total. The other is how fast the week's total itself should grow. Both have named, attributed guidance, and the second one is less settled than its reputation suggests.
On the first question, exercise physiologist Jack Daniels, in Daniels' Running Formula, ties the cap to weekly volume rather than using one flat number: under about 40 weekly miles (64km), no single long run should exceed 30% of that week's total; at 40 or more weekly miles, the cap drops to whichever is smaller, 25% of the week's mileage or 150 minutes. A runner logging 20 weekly miles falls in the lower tier, so the cap is 30% (about 6 miles), regardless of how good that run feels partway through. It's a ceiling on one session, not a target to hit every week.
On the second question (the "10% rule," never raising total weekly mileage by more than 10% over the week before), the evidence is thinner than the rule's reputation. A 2008 randomized controlled trial by Buist and colleagues, published in the American Journal of Sports Medicine, put 532 novice runners on either a standard 8-week programme or a graded 13-week programme built around the 10% rule, training all of them toward the same 4-mile event. Injury rates came back almost identical: 20.8% on the 10%-rule programme versus 20.3% on the standard one. A larger 2025 cohort study of more than 5,000 runners in the British Journal of Sports Medicine (Frandsen and colleagues) found that injury risk rose when a single run's distance exceeded a runner's own longest run of the previous 30 days by more than 10%, but also that smaller jumps weren't fully safe either, which the researchers themselves read as reason to question the 10% figure rather than confirm it. Read plainly: the 10% rule is a reasonable habit, not a proven injury shield. Use it as a rough guardrail, and pair it with a fitness and fatigue read as ambition builds, rather than trusting one number alone.
How far before a half marathon
Hal Higdon's Novice 1 half marathon plan, one of the most widely used structured plans for first-time half marathoners, runs 12 weeks: the opening long run is 3–4 miles, and the peak long run (reached in week 11) is 10 miles, not the full 13.1. Runners cover that last 3.1 miles for the first time on race day itself, carried by the taper, pacing and race-day atmosphere. If a half marathon is the actual goal, comfortably covering 3–4 miles is the realistic starting line for a plan like this, not 13.1 miles of base fitness built beforehand.
There's no "should": only your own last few weeks
Every number on this page is a published programme or someone else's cohort average. None of them describes any single runner reading it. A more useful daily question than "how far should I be able to run" is "how does this week compare to my last few," which is exactly what a running rank that moves with your own training, rather than a fixed distance target, is built to answer.
Build the distance, don't guess it
- Follow a plan instead of guessing. Runked's 5K training plan and half marathon training plan structure the week-by-week buildup instead of leaving distance to feel.
- Make consistency the actual goal. A running streak rewards showing up, which is what training age is really measuring.
- Know the actual number, not the guess. Runked's race time predictor estimates your current 5K, 10K, half and marathon numbers from recent training.
Find out where you stand
Runked is free on the App Store. Connect your watch or track 3 runs, and meet your Runk.
Download on App StoreFrequently asked questions
How far should a beginner run?
There's no fixed distance for a beginner: it depends on the week of training you're actually on. NHS's Couch to 5K programme, a free and widely used structure for exactly this stage, starts with 60-second running intervals in week 1 and builds to 30 minutes of continuous running by week 9. Start with time on your feet and interval structure, not a target number of kilometers.
Is 5K far enough?
For most goals, yes. 5K is a complete distance in its own right: it's the finish line of programmes like Couch to 5K, the standard parkrun distance, and plenty of dedicated runners never train beyond it. Whether it's "far enough" depends on what you're training for: someone after general fitness has already arrived, while someone training for a half marathon still has roughly 10 more miles of distance to build (a 5K is about 3.1 miles; a half marathon is 13.1).
How fast can I build distance safely?
There's no single validated number, despite how confidently the "10% rule" (never raise weekly mileage more than 10% over the week before) gets repeated. A 2008 randomized controlled trial by Buist and colleagues, published in the American Journal of Sports Medicine, found almost no difference in injury rates between novice runners on a standard training program and ones following a graded 10%-rule program (20.8% versus 20.3%). A 2025 cohort study of over 5,000 runners by Frandsen and colleagues in the British Journal of Sports Medicine found injury risk rose once a single run exceeded a runner's own longest run of the previous 30 days by more than 10%, and that even smaller jumps carried some elevated risk, which is why the researchers questioned whether 10% is the right threshold at all. Treat the rule as a rough guardrail, not a guarantee.
How far before a half marathon?
Less than the full 13.1 miles, in most structured plans. Hal Higdon's widely used Novice 1 half marathon plan runs 12 weeks and peaks at a 10-mile long run in week 11: runners cover the final 3.1 miles for the first time on race day itself, helped by taper, pacing and race-day adrenaline. A base of comfortably running 3 to 4 miles is the usual starting point before beginning a half marathon plan at all. Runked's PRO race-time predictor estimates where your current training would put you on half-marathon day, if you want a number before the taper starts.