How do I calculate my running pace?

Divide your total time by your total distance. For example, if you ran 5 miles in 45 minutes, your pace is 45 ÷ 5 = 9 minutes per mile. To convert seconds within the time, keep them as a decimal fraction of a minute (e.g., 45:30 = 45.5 minutes) before dividing.

What is a good running pace for beginners?

Most beginner runners fall in the 10:00-14:00 per mile range for easy runs, though pace varies enormously by age, fitness, and terrain. The better benchmark than a fixed number is effort level: an easy run pace should let you hold a conversation comfortably.

How accurate is Riegel's formula for predicting race times?

Riegel's formula is reasonably accurate (typically within a few percent) for predictions between distances in the 5K-to-marathon range when training is consistent. It becomes less reliable for very short distances (under 5K) where anaerobic speed dominates, or when comparing a runner with heavy endurance training against one with speed-focused training.

Why does the marathon prediction from my 5K time seem too fast?

Riegel's formula assumes ideal marathon-specific preparation, including adequate long runs and fueling. Many runners with strong 5K fitness but limited endurance-specific training run several minutes slower than the pure Riegel prediction because the marathon tests fueling and durability, not just aerobic speed.

What is the difference between pace and speed?

Pace measures time per unit distance (minutes per mile or kilometer) and is the standard unit for runners. Speed measures distance per unit time (miles per hour) and is more common in cycling. They are mathematical inverses: a 6:00/mile pace equals 10 mph.

How do I convert min/km pace to min/mile?

Multiply your min/km pace by 1.60934 (the number of kilometers in a mile). For example, a 5:00/km pace converts to 5.00 × 1.60934 = 8.05 minutes per mile, or roughly 8:03/mile.

What pace do I need to run a sub-4-hour marathon?

A 4:00:00 marathon requires an average pace of 9:09 per mile (240 minutes ÷ 26.219 miles), or 5:41 per kilometer. Most runners aim to run slightly faster than this average in the first half to bank a small cushion for the later miles.

Running Pace

Health & Fitness

Calculate running pace and split times

Distance

Time (hh:mm:ss)

Unit

Every runner eventually asks the same three questions: How fast am I actually running? What finish time should I expect on race day? And if I can run a 5K at a certain pace, what does that mean for my marathon? Answering these by hand means juggling minutes, seconds, and fractional miles or kilometers — easy to get wrong when you're tired and just want a number.

Our running pace calculator handles all three scenarios instantly. Enter a distance and a finish time to get your pace per mile or per kilometer. Enter a target pace and a distance to predict your finish time. Or enter a recent race result to predict your expected time at a different distance using Riegel's formula, the same exponential model used by exercise physiologists and race-prediction tools like those built into Garmin and Strava.

Whether you're pacing a training run, setting a goal split for race day, or figuring out whether your 5K fitness translates into a realistic marathon goal, this calculator converts your numbers in seconds so you can spend more time running and less time doing arithmetic.

Why Running Pace Matters

Pace is the single most useful number in distance running because it converts raw effort into a comparable, plannable metric. Without it, "I ran 6.2 miles in 52 minutes" tells you little about whether that's fast, sustainable, or appropriate for race day.

Training structure: Coaches build workouts around pace zones — easy pace, tempo pace, threshold pace, interval pace. Knowing your current pace lets you calculate these training zones correctly instead of guessing, which reduces injury risk from running too hard on easy days.

Race-day pacing: Starting a marathon 20 seconds per mile too fast feels harmless in mile 2 and catastrophic by mile 20 — the well-documented "wall" is frequently a pacing error, not just a fitness limit. A precomputed pace chart or split plan keeps you honest when adrenaline says go faster.

Goal-setting and race selection: Riegel-style predictions let you translate a known fitness level (say, a recent 10K) into a realistic goal time for an upcoming half marathon or marathon, so your training plan targets an achievable number instead of a guess.

The Running Pace Formula, Explained

Pace = Time / Distance; Finish Time = Pace × Distance; T2 = T1 × (D2/D1)^1.06

Where: Time = total elapsed time for the run, Distance = total distance covered (in miles or kilometers), Pace = time per unit distance (min/mile or min/km). For race prediction, T1 = your known finish time at a reference distance D1, D2 = the target distance you want to predict, and T2 = the predicted finish time at D2. The exponent 1.06 (Riegel's fatigue factor, developed by Pete Riegel in 1977) reflects the fact that runners slow down slightly as distance increases — doubling the distance more than doubles the time required, because endurance, fueling, and pacing discipline all become limiting factors at longer distances. Riegel's formula is most accurate when D1 and D2 are reasonably close (e.g., 5K to half marathon) and less reliable for extreme extrapolations like a mile time predicting a marathon.

How to Use the Running Pace: Step by Step

Choose your calculation mode
Select whether you want to calculate pace from a known distance and time, predict a finish time from a target pace and distance, or predict a race time at a new distance from a known result.
Enter your distance
Input the distance in miles or kilometers. For a known race result, use the official distance (5K = 3.107 miles, 10K = 6.214 miles, half marathon = 13.109 miles, marathon = 26.219 miles).
Enter your time or pace
Depending on the mode, enter your finish time (hours:minutes:seconds) or your target pace (minutes:seconds per mile or kilometer).
Select units
Choose miles or kilometers for pace display — the calculator converts automatically between the two so you can see both.
Review your results
For race prediction mode, review the predicted finish time at your target distance, and compare it against your training pace to check whether the goal is realistic.

Running Pace Examples: Real-World Scenarios

Finding Pace from a 10K Training Run

Dana runs a 10K training loop and finishes in 52 minutes 30 seconds. She wants her pace in both min/km and min/mile.

Distance:10 km

Time:52:30

Calculation

Pace per km = 52.5 min ÷ 10 km = 5.25 min/km. Distance in miles = 10 ÷ 1.60934 = 6.2137 miles. Pace per mile = 52.5 min ÷ 6.2137 miles = 8.449 min/mile

Result

Pace: 5:15 per kilometer, or 8:27 per mile. This falls in a solid moderate-effort training pace for most recreational runners.

Predicting a Marathon Time from a 5K Result

Marco just ran a 5K in 25:00. He wants to know what marathon finish time that fitness level predicts using Riegel's formula.

Known distance (D1):5 km

Known time (T1):25:00 (25.0 min)

Target distance (D2):42.195 km (marathon)

Calculation

T2 = 25 × (42.195/5)^1.06 = 25 × (8.439)^1.06 = 25 × 9.591 = 239.78 minutes

Result

Predicted marathon time: approximately 3:59:47. Note this is a fitness-based ceiling assuming proper marathon-specific training, fueling, and pacing — most runners run somewhat slower than the pure Riegel prediction at the marathon distance.

Predicting a 10K Time from a Half Marathon

Priya ran a half marathon in 1:45:00 and wants to estimate her equivalent 10K race time.

Known distance (D1):21.0975 km (half marathon)

Known time (T1):105 min

Target distance (D2):10 km

Calculation

T2 = 105 × (10/21.0975)^1.06 = 105 × (0.4740)^1.06 = 105 × 0.4532 = 47.59 minutes

Result

Predicted 10K time: approximately 47:35. Because the 10K is shorter and less endurance-limited, Priya's actual result may be faster than this prediction if she has good short-distance speed.

Common Mistakes to Avoid

Mixing units — entering a distance in kilometers but reading the result as min/mile (or vice versa) produces a pace that looks wrong by roughly 60%. Always confirm which unit the pace is displayed in.
Using Riegel's formula across wildly different distances, like predicting a marathon from a 400m time — the formula is calibrated for endurance-to-endurance comparisons and loses accuracy outside the 5K-to-marathon range.
Ignoring race-day variables — Riegel predictions assume similar terrain, weather, and training between the reference and target race. Heat, hills, and inadequate long-run training will slow actual results below the prediction.
Confusing pace and speed — pace (time per distance, e.g. 8:00/mile) and speed (distance per time, e.g. 7.5 mph) are inverses. Make sure you're entering values into the field that matches what you actually measured.

Tips & Tricks

Negative-split practice: aim to run the second half of a race slightly faster than the first half. Use the pace calculator to set an intentionally conservative early pace target.
Riegel predictions are most reliable when your reference race was run within the last 4-6 weeks under similar training conditions to your target race.
For race-day pacing, calculate your per-mile splits ahead of time and write them on your arm or set them as alerts on a GPS watch — deciding pace mid-race under fatigue is unreliable.

Pace is the language distance runners use to plan, train, and race intelligently, and this calculator removes the mental math so you can focus on execution. Use it to check your current training pace, build a race-day split plan, or set a realistic goal time based on a recent result. Pair it with our one rep max calculator if you're strength training alongside your running program, or check your heart rate zone calculator to make sure your easy-pace runs stay in the right aerobic zone.

Running Pace — Frequently Asked Questions

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Authoritative References

American College of Sports Medicine — Exercise Guidelines

acsm.org — Authoritative endurance training and exercise prescription guidance

CDC — Physical Activity Basics

cdc.gov — Government guidance on aerobic activity recommendations

External links open in a new tab. OmniCalc.us is not affiliated with these organisations.

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