To predict your marathon time from a 10K time, use the Riegel formula: Marathon Time = 10K Time × (42.195 / 10)^1.06. For example, if your 10K time is 45 minutes, your predicted marathon time is 45 × (4.2195)^1.06 = 45 × 4.62 = 208 minutes, or 3 hours 28 minutes. This calculator uses the Riegel, Cameron, and Daniels formulas to give you three predictions, so you can see the range.

The Riegel formula is: T2 = T1 × (D2/D1)^1.06, where T1 is your known race time, D1 is the known race distance, and D2 is the target race distance. The exponent 1.06 accounts for the fact that runners slow down slightly over longer distances. For example, to predict a marathon from a 10K: T2 = 10K time × (42.195/10)^1.06 = 10K time × 4.62. The formula works reasonably well for distances up to the marathon but becomes less accurate for ultramarathons.

A good marathon time for a beginner depends on age and fitness. Most first-time marathoners finish between 4:30 and 5:30. A reasonable target for a reasonably fit beginner is around 4:45-5:00. To achieve this, you should be able to run a 10K in around 55-60 minutes before starting marathon training. Most beginner training plans last 16-20 weeks and include one long run per week building up to 20+ miles.

Training paces are based on your current race fitness (typically your most recent race time or VDOT). The main training zones are: Easy pace (60-75 seconds slower per km than marathon pace), Marathon pace (your target marathon race pace), Threshold/Tempo pace (15-20 seconds faster per km than marathon pace), Interval pace (30-45 seconds faster per km), and Repetition pace (45-60 seconds faster per km). This calculator automatically generates all five training paces based on your predicted marathon time using Daniels’ VDOT system.

VDOT (V̇O2max Derived from Time) is a fitness index developed by Dr Jack Daniels that estimates your VO2max from a recent race performance. It’s calculated using the formula: VDOT = (-4.60 + 0.182258 × v + 0.000104 × v²) / (0.8 + 0.1875 × e^(-0.012778 × t) + 0.193265 × e^(-0.012778 × t)), where v is velocity in metres per minute and t is time in minutes. Your VDOT is then used to predict race times at all distances and to calculate training paces. A VDOT of 40-45 is typical for recreational runners, 50-55 for serious amateurs, and 60+ for competitive runners.

Marathon time predictors are generally accurate to within ±5-10 minutes for most runners, assuming you use a recent race performance (within the last 2-3 months) as your input. Accuracy depends on: how recently you raced, how well-trained you are for the marathon distance, course profile (hilly vs flat), and weather conditions. The Riegel formula tends to slightly underestimate marathon times for less experienced runners, while the Cameron formula is often more accurate for longer distances. Use the range of predictions to set a realistic goal.

A good half marathon time depends on your experience and fitness. Beginner runners typically finish in 2:15-2:30. Intermediate runners target 1:50-2:00. Advanced runners aim for 1:30-1:40. Elite runners complete a half marathon in under 1:15 (men) or 1:25 (women). To predict your half marathon time from a 10K, multiply your 10K time by approximately 2.14. For example, a 50-minute 10K predicts a half marathon time of about 1:47.

To convert from min/km to min/mile, multiply by 1.60934 (since 1 mile = 1.60934 km). For example, 5:00 min/km × 1.60934 = 8:03 min/mile. To convert from min/mile to min/km, divide by 1.60934. For example, 8:00 min/mile ÷ 1.60934 = 4:58 min/km. This calculator handles all conversions automatically — just select your preferred unit.

To predict your marathon time from a 10K time, use the Riegel formula: Marathon Time = 10K Time × (42.195 / 10)^1.06. For example, if your 10K time is 45 minutes, your predicted marathon time is 45 × (4.2195)^1.06 = 45 × 4.62 = 208 minutes, or 3 hours 28 minutes. This calculator uses the Riegel, Cameron, and Daniels formulas to give you three predictions, so you can see the range.

The Riegel formula is: T2 = T1 × (D2/D1)^1.06, where T1 is your known race time, D1 is the known race distance, and D2 is the target race distance. The exponent 1.06 accounts for the fact that runners slow down slightly over longer distances. For example, to predict a marathon from a 10K: T2 = 10K time × (42.195/10)^1.06 = 10K time × 4.62. The formula works reasonably well for distances up to the marathon but becomes less accurate for ultramarathons.

A good marathon time for a beginner depends on age and fitness. Most first-time marathoners finish between 4:30 and 5:30. A reasonable target for a reasonably fit beginner is around 4:45-5:00. To achieve this, you should be able to run a 10K in around 55-60 minutes before starting marathon training. Most beginner training plans last 16-20 weeks and include one long run per week building up to 20+ miles.

Training paces are based on your current race fitness (typically your most recent race time or VDOT). The main training zones are: Easy pace (60-75 seconds slower per km than marathon pace), Marathon pace (your target marathon race pace), Threshold/Tempo pace (15-20 seconds faster per km than marathon pace), Interval pace (30-45 seconds faster per km), and Repetition pace (45-60 seconds faster per km). This calculator automatically generates all five training paces based on your predicted marathon time using Daniels' VDOT system.

VDOT (V̇O2max Derived from Time) is a fitness index developed by Dr Jack Daniels that estimates your VO2max from a recent race performance. It's calculated using the formula: VDOT = (-4.60 + 0.182258 × v + 0.000104 × v²) / (0.8 + 0.1875 × e^(-0.012778 × t) + 0.193265 × e^(-0.012778 × t)), where v is velocity in metres per minute and t is time in minutes. Your VDOT is then used to predict race times at all distances and to calculate training paces. A VDOT of 40-45 is typical for recreational runners, 50-55 for serious amateurs, and 60+ for competitive runners.

Marathon time predictors are generally accurate to within ±5-10 minutes for most runners, assuming you use a recent race performance (within the last 2-3 months) as your input. Accuracy depends on: how recently you raced, how well-trained you are for the marathon distance, course profile (hilly vs flat), and weather conditions. The Riegel formula tends to slightly underestimate marathon times for less experienced runners, while the Cameron formula is often more accurate for longer distances. Use the range of predictions to set a realistic goal.

A good half marathon time depends on your experience and fitness. Beginner runners typically finish in 2:15-2:30. Intermediate runners target 1:50-2:00. Advanced runners aim for 1:30-1:40. Elite runners complete a half marathon in under 1:15 (men) or 1:25 (women). To predict your half marathon time from a 10K, multiply your 10K time by approximately 2.14. For example, a 50-minute 10K predicts a half marathon time of about 1:47.

To convert from min/km to min/mile, multiply by 1.60934 (since 1 mile = 1.60934 km). For example, 5:00 min/km × 1.60934 = 8:03 min/mile. To convert from min/mile to min/km, divide by 1.60934. For example, 8:00 min/mile ÷ 1.60934 = 4:58 min/km. This calculator handles all conversions automatically — just select your preferred unit.

To predict your marathon time from a 10K time, use the Riegel formula: Marathon Time = 10K Time × (42.195 / 10)^1.06. For example, if your 10K time is 45 minutes, your predicted marathon time is 45 × (4.2195)^1.06 = 45 × 4.62 = 208 minutes, or 3 hours 28 minutes. This calculator uses the Riegel, Cameron, and Daniels formulas to give you three predictions, so you can see the range.

The Riegel formula is: T2 = T1 × (D2/D1)^1.06, where T1 is your known race time, D1 is the known race distance, and D2 is the target race distance. The exponent 1.06 accounts for the fact that runners slow down slightly over longer distances. For example, to predict a marathon from a 10K: T2 = 10K time × (42.195/10)^1.06 = 10K time × 4.62. The formula works reasonably well for distances up to the marathon but becomes less accurate for ultramarathons.

A good marathon time for a beginner depends on age and fitness. Most first-time marathoners finish between 4:30 and 5:30. A reasonable target for a reasonably fit beginner is around 4:45-5:00. To achieve this, you should be able to run a 10K in around 55-60 minutes before starting marathon training. Most beginner training plans last 16-20 weeks and include one long run per week building up to 20+ miles.

Training paces are based on your current race fitness (typically your most recent race time or VDOT). The main training zones are: Easy pace (60-75 seconds slower per km than marathon pace), Marathon pace (your target marathon race pace), Threshold/Tempo pace (15-20 seconds faster per km than marathon pace), Interval pace (30-45 seconds faster per km), and Repetition pace (45-60 seconds faster per km). This calculator automatically generates all five training paces based on your predicted marathon time using Daniels' VDOT system.

VDOT (V̇O2max Derived from Time) is a fitness index developed by Dr Jack Daniels that estimates your VO2max from a recent race performance. It's calculated using the formula: VDOT = (-4.60 + 0.182258 × v + 0.000104 × v²) / (0.8 + 0.1875 × e^(-0.012778 × t) + 0.193265 × e^(-0.012778 × t)), where v is velocity in metres per minute and t is time in minutes. Your VDOT is then used to predict race times at all distances and to calculate training paces. A VDOT of 40-45 is typical for recreational runners, 50-55 for serious amateurs, and 60+ for competitive runners.

Marathon time predictors are generally accurate to within ±5-10 minutes for most runners, assuming you use a recent race performance (within the last 2-3 months) as your input. Accuracy depends on: how recently you raced, how well-trained you are for the marathon distance, course profile (hilly vs flat), and weather conditions. The Riegel formula tends to slightly underestimate marathon times for less experienced runners, while the Cameron formula is often more accurate for longer distances. Use the range of predictions to set a realistic goal.

A good half marathon time depends on your experience and fitness. Beginner runners typically finish in 2:15-2:30. Intermediate runners target 1:50-2:00. Advanced runners aim for 1:30-1:40. Elite runners complete a half marathon in under 1:15 (men) or 1:25 (women). To predict your half marathon time from a 10K, multiply your 10K time by approximately 2.14. For example, a 50-minute 10K predicts a half marathon time of about 1:47.

To convert from min/km to min/mile, multiply by 1.60934 (since 1 mile = 1.60934 km). For example, 5:00 min/km × 1.60934 = 8:03 min/mile. To convert from min/mile to min/km, divide by 1.60934. For example, 8:00 min/mile ÷ 1.60934 = 4:58 min/km. This calculator handles all conversions automatically — just select your preferred unit.