12-Week Marathon Training Plan — Free Week-by-Week Schedule

Twelve weeks is enough to prepare for a marathon — if you already have an aerobic base of 30-40 km per week. This guide walks you through each phase week by week, linking to the exact tools you need at every step. Generate your personalized plan with our Training Plan Generator, then follow this guide to execute it.

Before You Start: The Baseline Check

Before committing to a 12-week plan, make sure you meet these prerequisites:

• Currently running 3-4 times per week
• Comfortable running 30-40 km per week
• Can complete a 15-18 km long run without injury
• Have a recent race result (5K, 10K, or half marathon) for pace calibration

Plug your recent race time into the Race Time Predictor to get a realistic marathon goal. Then use the Pace Calculator to find your training zones — you will need your easy pace, tempo pace, and marathon pace for the weeks ahead.

Phase 1: Base Building (Weeks 1-4)

The first four weeks are about establishing your training rhythm and gently increasing volume. You should feel comfortable, never exhausted.

Week 1-2: Foundation

Run 4 days per week: 3 easy runs (30-45 min) + 1 long run. Keep all runs at easy pace — use your Heart Rate Zones to stay in Zone 2 (conversational effort). Your long run should be 14-16 km.

Week 3-4: Building

Increase weekly volume by 10%. Add 5 minutes to each easy run and 2 km to the long run. Introduce one strides session after an easy run: 6-8 x 100m accelerations at near-sprint effort with full recovery. This develops running economy without adding fatigue.

At the end of Week 4, your long run should reach 18-20 km. Use the Mileage Increase Planner to verify your volume progression is safe.

Phase 2: Strength Building (Weeks 5-8)

This is where the real marathon fitness develops. You introduce quality sessions and your long runs start to simulate race conditions.

Week 5-6: Tempo Introduction

Weekly structure: 2 easy runs + 1 tempo session + 1 long run. Your tempo run should be 20-30 minutes at tempo pace (comfortably hard, about 85-88% max HR). Sandwich the tempo effort between a 15-minute warm-up and cool-down jog. If your plan includes interval sessions, use the Interval Calculator to generate workouts with precise paces and recovery times matched to your current fitness.

Long runs grow to 22-24 km. Start practicing your race nutrition strategy on every long run over 20 km — take a gel every 45 minutes, exactly as you plan to on race day.

Week 7-8: Peak Quality

This is the hardest phase. Weekly structure: 1 easy run + 1 tempo + 1 marathon-pace session + 1 long run.

The marathon-pace session is critical: run 10-14 km at your goal marathon pace. This teaches your body what race effort feels like and builds confidence. Include it in the middle of the week, with at least 2 recovery days before the weekend long run.

Long runs reach 28-32 km in Weeks 7-8. These are your most important training sessions. Run them at easy pace but include the final 6-8 km at marathon pace to simulate the late-race feeling. Track your hydration needs during these runs — dehydration at this distance will teach you exactly how much fluid you need on race day.

Week 8 is the peak week. After this, volume begins to decrease. Use our Training Load Calculator to check your fatigue and fitness levels.

Phase 3: Race Preparation (Weeks 9-10)

Volume starts decreasing but intensity stays. You are sharpening, not building. Think of these weeks as polishing the fitness you have already built.

Week 9: Moderate Reduction

Cut total weekly volume by 15-20%. Keep one tempo run and one marathon-pace session, but make them shorter (15-20 min tempo, 8-10 km at MP). Long run drops to 22-24 km.

This is the time to finalize your race plan. Generate your pace band wristband and race splits. Know exactly what pace you need at every kilometer.

Week 10: Further Reduction

Cut volume by 25-30% from peak. Long run drops to 16-18 km. Include 3 km at marathon pace in the middle. Keep strides sessions for neuromuscular maintenance.

Check the weather forecast for race day. If heat is expected, use the Heat Adjustment Calculator to revise your pace target. Check wind conditions for course-specific strategy.

Phase 4: Taper and Race Week (Weeks 11-12)

The Taper Calculator will generate your exact reduction schedule. Trust the taper — you will feel sluggish and anxious. This is normal. Your body is storing glycogen and repairing micro-damage from months of training.

Week 11: Pre-Race Week

Run 3-4 times, all easy, totaling 40-50% of your peak volume. Include one short tempo (10-12 min) to keep your legs sharp. Your longest run should be 10-12 km.

Start carb loading on Thursday or Friday (2-3 days before race). Plan your race morning timeline so you know exactly when to wake up, eat, and leave for the start area.

Week 12: Race Week

Monday-Wednesday: 2-3 very short, easy runs (15-20 min each). Thursday: rest or 10-minute shakeout jog. Friday: rest. Saturday: race day.

Use the Race Day Checklist to make sure you have not forgotten anything. Lay out all gear the night before. Attach your pace band to your wrist. Pin your bib. Sleep early — even if you cannot sleep well, the rest matters.

Race Day Execution

The most important rule: start slow. Your first 5 km should feel almost too easy. If you are on pace at 10 km, you are exactly where you need to be. The race truly begins at 30 km — save your energy for when it matters most.

Follow your gel schedule religiously. Take fluids at every aid station. If conditions are warm, use the What to Wear recommendations and start hydrating early.

When the wall hits — and it will, somewhere between 30-38 km — remember: you trained for this moment. Shorten your stride, maintain cadence, and focus on one kilometer at a time. You are a marathoner.

Your Toolkit for 12 Weeks

If this is your first marathon, our First Marathon Training Guide provides essential context on building up to race day. As you enter the final weeks, our Marathon Tapering Guide details exactly how to reduce volume without losing fitness.