Running Pace Calculator
Distance and time in — pace, speed, and your projected finish times for every classic race distance.
Calculate your pace
The three-way relationship
Run 5 miles in 45 minutes and your pace is 9:00 per mile (5:36/km), or 6.67 mph. The same arithmetic projects finish times: that pace yields a 27:58 5K, a 55:56 10K, just under 1:58 for a half marathon — though projections to longer races are optimistic, because nobody holds 5-mile pace for 26.2 miles without specific training.
Predicting race times honestly
The flat-pace projections above assume identical effort across distances, which physiology declines to provide. Runners typically slow ~5–6% each time distance doubles (the basis of Riegel's prediction formula). Practical reading: your 5K pace minus ~20–30 seconds per mile approximates 10K pace; add ~30–40 seconds to 10K pace for half-marathon pace. The longer the target race, the more the prediction depends on your weekly mileage rather than your speed.
Using pace in training
Most effective training happens slower than race pace: the standard structure puts roughly 80% of weekly running at a conversational pace — often 60–90 seconds per mile slower than 5K pace — with the remaining 20% as quality work (tempo runs near one-hour-race effort, intervals at 5K pace or faster). Runners who do every run at medium-hard pace plateau; the easy/hard split is the most reliable improvement lever in the sport. Use this calculator to find your zones, then have the discipline to actually run the easy ones easy.
Frequently asked questions
What's a good pace for a beginner?
Whatever pace lets you finish the distance comfortably — commonly 10–13 minutes per mile, often with walk breaks. Pace improves automatically with consistent weeks; chasing speed first is how beginners get injured.
How do treadmill paces compare to outdoor?
Treadmills remove wind resistance, so the same setting feels slightly easier; a 1% incline approximates outdoor effort. Treadmill calibration also varies — trust effort and heart rate over the display.
How accurate are the marathon projections?
Flat-pace extrapolation flatters you. From a 5K time, a realistic marathon is closer to your pace plus 45–60+ seconds per mile, and only with marathon-specific training volume. Race predictors like Riegel's formula bake in the slowdown.
What pace do I need for a sub-30 5K or sub-4 marathon?
Sub-30 5K: 9:39/mi (6:00/km). Sub-25: 8:03/mi. Sub-2 half: 9:09/mi. Sub-4 marathon: 9:09/mi as well — held for twice as long, which is the whole sport in one sentence.
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How running pace, time, and distance relate
Running calculations involve three variables: pace (time per unit distance), total time, and total distance. Know any two, calculate the third. The formulas: Pace = Time ÷ Distance. Time = Pace × Distance. Distance = Time ÷ Pace. All three are simple division, but working in mixed time units (hours, minutes, seconds) requires care with unit conversion.
Common race distance reference points: 5K = 3.107 miles. 10K = 6.214 miles. Half marathon = 13.109 miles. Full marathon = 26.219 miles. Ultramarathon distances vary (50K, 50 miles, 100 miles, and beyond).
Finish time targets at common paces
5K targets: 8:00/mile pace = 24:51. 9:00/mile = 27:58. 10:00/mile = 31:04. 12:00/mile = 37:17.
Half marathon targets: 8:00/mile = 1:44:52. 9:00/mile = 1:57:59. 10:00/mile = 2:11:05. 12:00/mile = 2:37:19.
Full marathon targets: 8:00/mile = 3:29:45. 9:00/mile = 3:55:58. 10:00/mile = 4:22:11. 12:00/mile = 5:14:34.
Running in Las Vegas — heat and terrain considerations
Las Vegas offers excellent winter running conditions (October–April: 45–75°F, low humidity, abundant sunshine) and genuinely challenging summer conditions. During June–September, surface temperatures on pavement can reach 150°F at midday — substantially above ambient air temperature. For summer running in Las Vegas: start before 6 AM or after 7 PM, carry 20 oz of water per hour minimum, reduce pace expectations by 60–90 seconds per mile in extreme heat, and watch for heat exhaustion symptoms (dizziness, nausea, stopping sweating).
Red Rock Canyon, 17 miles west of Las Vegas, offers world-class trail running at 3,000–7,000 feet elevation — significantly cooler than the valley floor in summer. The calico hills and sandstone terrain require trail-specific footwear and pace adjustments for technical sections.
Frequently asked questions
What is a good running pace for a beginner?
For most beginners, a conversational pace — where you can speak in full sentences without gasping — is the right target. This typically falls between 10–14 minutes per mile depending on fitness level. Running at a pace where you cannot hold a conversation means you are anaerobic, which is not sustainable for building aerobic base.
How much does temperature affect running pace?
Significantly. Research suggests performance declines approximately 0.4% for every degree Fahrenheit above 55°F. At 90°F, expect a pace 14% slower than your cool-weather effort for the same perceived exertion. At 105°F (Las Vegas summer), that can be 20% or more. Adjust finish time goals accordingly when racing or training in heat.
What pace should I target for a sub-2-hour half marathon?
A sub-2:00 half marathon requires maintaining 9:09 per mile (5:41 per km) for 13.109 miles. Most coaches recommend training at 9:30–10:00/mile for most runs and doing a few workouts at race pace (9:09) to develop pace feel and lactate threshold.
How do I convert kilometers to miles for pace?
1 mile = 1.60934 km. A 5:00/km pace equals approximately 8:03/mile. A 6:00/km pace equals approximately 9:40/mile. Treadmill speeds are typically displayed in mph: 6 mph = 10:00/mile, 7 mph = 8:34/mile, 8 mph = 7:30/mile.
Disclaimer: Pace calculations are mathematical estimates. Actual race performance depends on fitness, conditions, terrain, and many other factors. Consult a coach for personalized training guidance.