A 12-Week Half Marathon Training Plan for First-Timers

This plan assumes you can currently run 5 kilometres without stopping, and comfortably, meaning you finish able to hold a conversation rather than gasping through the last kilometre, and have been running at least twice a week for the last month. That base matters more than it sounds like it should: 12 weeks is enough time to build a half marathon on top of existing fitness, but it isn't really enough time to build the fitness itself and then layer 21.1 km of progressive long runs over it. If that's not quite you yet, spend two to three weeks building that base first, our zero-to-running guide covers exactly that groundwork, and building an aerobic base explains why rushing this step tends to cost you later in a plan rather than at the start of one. If you're already there, this plan takes you from a comfortable 5K to a finished half marathon in 12 weeks, with a weekly time commitment that starts around 3-4 hours and grows to 5-6 hours in the peak block before dropping sharply during the taper.

How this plan is structured

Four runs a week: one easy run, one workout (intervals or tempo), one medium run, and one long run that grows steadily most weeks. Two full rest or cross-training days sit around them, not squeezed in as an afterthought. The long run is the backbone of the entire plan, it's what actually prepares your legs and your patience for 21.1 km, and everything else in the week exists to support it: the easy run keeps blood flowing without adding fatigue, the workout builds the speed and muscular endurance that make race pace feel more manageable, and the medium run adds volume without the wear of a second hard effort. Effort matters more than pace here. Your easy runs should feel genuinely easy, conversational, the kind of pace where you could answer a question in full sentences without gasping, not a slow version of hard. Workouts should feel comfortably hard, an effort you can sustain for the prescribed reps but wouldn't want to hold much longer. If every run in a week feels roughly the same effort, something's off, and it's usually that the easy days are too fast.

The plan, week by week

Choosing a half marathon that fits this plan's timeline

Twelve weeks sounds precise on paper, but race calendars rarely cooperate exactly, so build in a few days of buffer on either end rather than trying to hit day 84 on the nose. Count backward from race day to find your week 1 start date, and if the closest logical Monday lands a few days off from a clean 12-week block, start a week early and treat the extra week as another easy one rather than compressing the build at the back end to make the math work. Choosing a race date walks through this in more detail if you haven't picked a race yet.

Course and season matter more for a half marathon than most first-timers expect going in. A flat, well-shaded course is meaningfully easier to pace evenly than a rolling one, and if you're choosing between two races roughly the same distance out on the calendar, that difference is worth weighing over a bigger city name. In India specifically, most organizers schedule half marathons between October and March for good reason, training through peak summer heat or racing through monsoon humidity adds a layer of difficulty this plan doesn't need to account for if you have the flexibility to avoid it. Flat vs hilly course training and how to choose your next marathon (the reasoning applies just as well one distance down) go deeper on both. Before you register, also check the event's cutoff time, most half marathons allow 3 to 3.5 hours, which this plan comfortably prepares you for, but it's worth confirming rather than assuming. Marathon cutoff times explained covers how organizers usually set these.

Strength and cross-training to layer in alongside the running

The two non-running days in this plan aren't rest by default, they're where you build the durability that carries you through weeks 5 to 10 without a minor niggle turning into a real injury. Two short bodyweight strength sessions a week, 20 to 30 minutes each, covering squats, lunges, single-leg glute bridges, and planks, do more for injury prevention over 12 weeks than almost anything else you could add to this plan. Strength training for runners has a fuller routine if you want a structured one to follow. The point isn't to get stronger in a gym sense, it's to give your hips and glutes the stability to keep absorbing the same repetitive impact week after week without something else quietly compensating until it complains.

Low-impact cross-training, cycling, swimming, or an elliptical, is a reasonable substitute on a day you want to move without adding running load, especially if you're nursing a minor ache or just want variety in the week. What doesn't work as well is using a cross-training day for something leg-heavy the day before a long run or workout, that just relocates the fatigue rather than resolving it. If a niggle does turn into something more persistent, cross-training for injured runners covers how to hold onto some fitness without making it worse.

What easy pace and workout effort should actually feel like

Every pace column in the schedule above is really an effort level in disguise, and reading it that way matters more than hitting exact minute-per-kilometre splits, especially in the early weeks. Easy pace should feel conversational: if you can comfortably answer a question in full sentences without needing to catch your breath first, you're at roughly the right effort. Most beginners run their easy days meaningfully faster than this, treating 'easy' as a label rather than an instruction, and pay for it with tired legs on the days that are actually supposed to build fitness.

Workout effort is different but isn't all-out either. Pickups and tempo segments should feel comfortably hard, an effort you'd describe as a 7 or 8 out of 10, sustainable for the prescribed distance or time but not something you'd want to hold for another ten minutes past it. If you're finishing workout reps able to sprint the last stretch, the effort was too easy; if you're slowing down or stopping mid-rep, it was too hard. The middle ground, uncomfortable but controlled, is where the actual fitness gets built.

If you don't have a coach or a recent race time to calibrate against, perceived effort vs pace is worth reading before week 1. It's a more reliable guide through the early part of this plan than any pace chart, because your easy pace on a humid evening and your easy pace on a cool morning can differ by 30 to 45 seconds per kilometre for the identical effort, and effort, not the number on your watch, is what the plan is actually asking for.

What a realistic finish time looks like

It's tempting to pick a goal time before you've run a single week of this plan, but it's more useful to let the plan tell you, roughly, where you land. A reasonable way to estimate is to look at your easy pace during the peak weeks (around week 9 or 10) and expect race day, with taper freshness and adrenaline, to run somewhat faster than that rather than slower. Most first-time half marathoners following a structured 12-week plan like this one finish comfortably somewhere in the 2:00 to 2:45 range, and the biggest single factor in where you land within it is usually how evenly the race is paced, not how fast the first 5 km felt. Understanding race splits and pacing and how to pace a negative split are worth reading in the final few weeks, once you have a real sense of your fitness rather than a guess. Whatever number you land on, hold it as a range rather than a deadline, the actual goal of a first half marathon is finishing strong enough to want to sign up for another one.

How to adjust this plan

• If a week feels too much, repeat the previous week instead of skipping ahead. Losing a week to fatigue is cheaper than losing two weeks to injury.
• Cutback weeks (4, 7, 11) exist on purpose, don't skip them just because you're feeling strong. They're what let weeks 5-10 actually work.
• If you miss a run, don't try to make it up by doubling the next one. Just continue the schedule from where you are.
• Hot, humid weeks (most of India, most of the year) may mean slowing your easy pace by 30-45 seconds per km to keep effort honest. See training through the monsoon and heat acclimatisation for specifics.
• A cold or mild illness above the neck, sniffles, a scratchy throat, no fever, usually just means an easier week, not a skipped one. Anything below the neck, chest congestion, fever, body aches, is a real stop-and-rest signal, running through it tends to extend the illness rather than shorten the disruption to training.
• Travel that costs you a long run is more disruptive than travel that costs you an easy run. If a trip forces a choice, protect the long run and let the weekly total flex around it instead.
• A missed week here and there in the first eight weeks is recoverable by simply continuing forward from wherever you are. A missed week in weeks 9-11, right before the taper, is worth handling deliberately rather than assuming it works itself out, adjusting training after a missed week covers how.

The three mistakes that derail this plan

Running every easy run too fast is the biggest one, and it's sneaky because it doesn't feel like a mistake in the moment, it feels like progress. The problem shows up two or three weeks later as workouts that feel harder than they should and long runs where the last few kilometres fall apart, because the easy days never actually let you recover. Skipping the taper is second, and just as counterintuitive: cutting volume in the final two weeks when you're fit and eager to keep building feels like giving something up, but it's precisely what lets that fitness show up on race day rather than staying buried under accumulated fatigue. Tapering explained goes into why this works, if you want the reasoning rather than just the instruction. Trying anything new on race morning, a shoe, a gel, a breakfast, even a pair of socks, is the third mistake, and it's the easiest one to avoid entirely: everything you plan to use on race day should already have appeared in at least two or three long runs before you rely on it. Choosing the right running socks, how to choose running shoes for your first race, and what to eat the week before a marathon (the logic applies to a half marathon's final week too) all cover pieces of this.