How much slower should training pace be than race pace?
Easy training pace should be 60-90 seconds per km slower than your 5K race pace. Marathon training pace matches goal race pace. Long runs are done 45-60 seconds slower than marathon pace. Only tempo runs, intervals, and race-specific workouts approach race pace.
The relationship between training pace and race pace depends on which session you're talking about. Easy runs (which should be 70-80% of your weekly mileage) are 60-90 seconds per km slower than your 5K race pace. If you run 5K in 25 minutes (5:00/km), your easy pace is around 6:00-6:30/km. Long runs are typically 30-60 seconds slower than marathon pace. If goal marathon pace is 5:30/km, long runs are at 6:00-6:30/km. Tempo runs sit at roughly half marathon race pace, or 15-30 seconds per km slower than 10K pace. Intervals are run at 5K race pace (for VO2max work) or 3K race pace (for speed). Race pace itself is only sustained during actual races or specific goal-pace workouts in the final 6-8 weeks before a target race. The biggest mistake runners make is running easy days at 'race pace minus 20 seconds' — that's still moderate intensity and prevents both aerobic development and hard-session recovery. True easy pace should feel easy, not just 'not hard.' If your easy runs feel like you could race at that pace, they're too fast. Use a pace calculator or VDOT tables to get exact numbers for each session type.