How to build a 16-week marathon plan that ends on race day

How do you work back from race day?

The final week contains your race. Its Monday is the anchor: move back 15 whole weeks to find the start of a 16-week schedule. For a Sunday race, that is 111 days before race day. The plan ends on the date you selected.

A race on another weekday still uses the Monday of its race week. The final week may contain fewer runs because the planner schedules nothing after the race. Check that week separately rather than expecting the usual weekly run count.

What should you enter as your starting point?

Choose 16 weeks, 3 to 6 runs per week and your current long-run distance in miles or kilometres. Use a distance that reflects your current running, rather than the distance you hope to reach later.

The planner supports 12 to 20 weeks, but the number of available weeks does not establish whether a marathon is suitable for you. It cannot assess your fitness, health or recovery. Its other sessions have fixed weekdays and leave their distance or duration for you to choose.

What does the 16-week example look like?

Enter Sunday 25 April 2027, 16 weeks, 4 runs per week and a current long run of 8 miles. The tool starts on 4 January. These selected weeks show how the long-run target changes:

The race replaces the final long run. World Athletics specifies a marathon distance of 42.195 km. The table's training distances are StrideSheet planning targets, not a distance prescription from World Athletics.

How do cutback weeks and taper work?

The underlying long-run progression rises in a straight line towards 20 miles or 32 km. Every fourth build week uses 80% of that week's calculated distance, then rounds to half a mile or one kilometre. Those unit-specific peak targets are separate planning rules; they are not exact conversions of each other.

The final three weeks are marked as taper. Their long runs are 75% of the planning peak, then 50%, then the race. For this mile-based example, that produces 15 miles, 10 miles and race day.

Other plan lengths can put the final build week on a cutback. The tool then shows a scheduled peak below the nominal target, while taper still uses the nominal target. Read the result's explanation when changing the plan length.

How do you use the finished schedule?

Read each week's dates and run details, including the shorter weeks. Save PDF or Print keeps the full schedule together; the calendar download creates an all-day entry for each run so you can choose its start time. Rebuild after changing inputs to update the displayed plan and exports.

The CDC and UK Chief Medical Officers provide general physical activity guidance. They do not validate this exact 16-week progression or determine your individual readiness. Use the schedule as a planning aid, and speak to your doctor about health concerns or a qualified coach about adapting your training.