The rule of the long run
The weekly long run is the backbone of marathon preparation. Build distance by no more than 2-3 km per week to protect tendons and joints.
First marathon guide
How to train for your first marathon: the complete guide
Training for your first marathon does not require extreme 80-mile weeks. Here is how to safely map out your first marathon training block, build your long run to 32 km (20 miles), and cross the finish line injury-free.
Included on this page
16 to 20-week progressive structure
Long run builds safely from 14 km to 32 km
Includes dedicated cutback weeks and 3-week taper
Free resource
Free 16-week first marathon roadmap
Use this 16-week progression as a template. Runapt customizes paces and schedule around your current weekly mileage.
- 16 to 20-week progressive structure
- Long run builds safely from 14 km to 32 km
- Includes dedicated cutback weeks and 3-week taper
WhenSessionHow to run it
Weeks 1-4Base buildingEstablish consistency at 30-40 km/week with 14-18 km long runs
Weeks 5-8Aerobic expansionIntroduce steady marathon-pace blocks and 20-24 km long runs
Weeks 9-12Peak mileage blockLongest runs (28-32 km) with mid-week threshold sessions
Weeks 13-16Taper and race3-week structured volume reduction to arrive fresh on race morning
Training notes
Make the plan fit the runner.
Respect the cutback weeks
Every 3-4 weeks, drop your long run and weekly mileage by 20-30% to allow your body to absorb training and rebuild muscle tissue.
Easy pace is your superpower
Over 80% of your marathon training should be at a conversational, easy aerobic effort. Running too fast on easy days causes overtraining.
How to map out training for your first marathon
Preparing for your first 42.195 km (26.2 mile) race is fundamentally about consistency and aerobic capacity. The goal for a first-timer is not blistering speedwork; it is teaching your body to burn fat efficiently, tolerate hours on your feet, and manage in-race nutrition.
A typical first marathon training block lasts 16 to 20 weeks. Before starting week 1, you should ideally have a consistent base of running 25–35 km (15–22 miles) per week for at least 6–8 weeks.
Building the long run safely
Your long run should start around 14–16 km and progress gradually up to 30–32 km (18–20 miles) about three to four weeks before race day. There is rarely a need for a first-time marathoner to run the full 42 km in training; the risk of injury and fatigue far outweighs the physiological benefit.
Practice your race-day fueling (energy gels, hydration, electrolytes) during every long run over 90 minutes so your stomach is trained well before the starting gun.
How a 3-week taper delivers peak performance
Three weeks out from race day, you begin the taper. You will reduce total weekly mileage by ~20% in week 14, ~40% in week 15, and ~60% in race week, while keeping short bursts of marathon-pace running to maintain neuromuscular sharpness. You will arrive at the start line feeling energized and fully recovered.
FAQ
How many months do I need to train for my first marathon?
Most coaches recommend 4 to 6 months (16 to 24 weeks), assuming you can already run 8-10 km continuously before starting.
How many miles per week is necessary for a first marathon?
Most first-time runners succeed on 45–65 km (28–40 miles) per week across 4 running days.
What is the longest run you should do before a marathon?
For first-timers, a peak long run of 30 to 32 km (18 to 20 miles) is the ideal balance between endurance building and safe recovery.
Can Runapt build a custom first marathon plan for me?
Yes. Runapt calculates your marathon paces using VDOT, builds a progressive plan around your available training days, and dynamically adjusts the schedule if you miss a run or need extra recovery.
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Use a marathon pace chart for common finish goals, with guidance for turning goal pace into adaptive training.
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Calculate VDOT-based easy, marathon, threshold, interval, and repetition training paces from a recent race result. Plan your pace zones for free!
Open guide →Marathon
Marathon training needs more than a PDF.
Train for a marathon with adaptive long-run progression, VDOT paces, fatigue modeling, AI coach notes, routes, and race strategy.
Open guide →Adaptive plan
Want this adjusted to your fitness, recovery, and schedule?
Start your Runapt plan and turn this calculator or sample structure into a race block that adapts when life changes.