Running pace is the time it takes to cover one mile or kilometer and is the primary metric for planning and executing every training run and race. Whether you are targeting a 5K personal best or pacing a first marathon, understanding the relationship between distance, time, and pace is essential for smart training and race execution.
Calculate Pace
How to Use the Running Pace Calculator
The running pace calculator helps you understand the three key variables of any run: pace, time, and distance. Knowing any two of them lets you calculate the third instantly, making it an essential tool for race planning, interval training, and pacing strategy.
Step 1: Choose Your Mode
Select from three calculation modes using the buttons at the top. Pace mode takes a distance and time and tells you your pace per mile and per kilometer. Finish Time mode takes a distance and a target pace and calculates your expected finish time. Distance mode takes a time and a pace and calculates how far you will travel.
Step 2: Pick a Distance or Enter Your Own
Use the preset buttons — 5K, 10K, Half Marathon (13.1 mi), or Marathon (26.2 mi) — to fill the distance field instantly. For trail runs, time trials, or custom workouts, type any distance directly. Switch between miles and kilometers using the unit toggle at the top of the page.
Step 3: Enter Time or Pace
Enter time in hours, minutes, and seconds. For pace, enter the minutes and seconds per mile (or per kilometer when in km mode). The calculator accepts any valid time values — no need to worry about formatting.
Step 4: Read Your Results
After clicking Calculate, you will see four result cards showing pace per mile, pace per km, finish time, and distance. Below that, a splits table shows your expected cumulative time at every mile or kilometer marker. Use this to set your watch alarms or plan your effort for each segment of the race.
Understanding the Race Predictor
The race predictor uses the Riegel formula — one of the most respected models in competitive running — to estimate your finish time for four common race distances based on your current performance. The formula (T2 = T1 × (D2 ÷ D1) ^ 1.06) accounts for the physiological reality that pace slows as race distance increases. The predictions are most accurate when extrapolating between similar distances (e.g., predicting a 10K from a 5K) and less reliable across very large gaps in distance.
FAQ
Is this running pace calculator free to use?
Yes, the running pace calculator is completely free with no limits or signup required. All calculations run locally in your browser, so no data is sent to any server.
How do I calculate my running pace?
Enter your race distance and total finish time in the Pace mode. The calculator divides your total time by the distance to give you your average pace per mile and per kilometer. For example, finishing a 5K in 25 minutes gives you a pace of 8:03 per mile or 5:00 per km.
What is the Riegel race predictor formula?
The Riegel formula predicts your finish time for one race distance based on a known result from another. The formula is T2 = T1 × (D2 / D1) ^ 1.06, where T1 is your known time and D1 and D2 are the two distances. It accounts for the fact that pace slows slightly as distance increases, making it one of the most accurate race prediction methods available.
How accurate is the race time predictor?
The Riegel formula is accurate within 2–5% for most recreational and competitive runners when predicting across similar distances (e.g., 10K from a 5K time). Accuracy decreases when predicting across very different distances (e.g., marathon from a 1 mile time) or if your training is highly specialized for one distance.
What distance presets are available?
The calculator includes preset buttons for 5K (3.107 miles), 10K (6.214 miles), Half Marathon (13.1 miles / 21.097 km), and Marathon (26.2 miles / 42.195 km). You can also enter any custom distance in miles or kilometers.
Can I switch between miles and kilometers?
Yes, there is a unit toggle at the top of the calculator. Switching between miles and kilometers instantly converts all displayed values, presets, splits tables, and race predictor results to the selected unit.
What does the splits table show?
The splits table shows your expected time at each mile or kilometer marker based on your calculated pace. This helps you plan even splits during a race and know exactly what time to hit at each checkpoint.
What is a good running pace for beginners?
A comfortable beginner running pace is typically between 10–14 minutes per mile (6:00–8:45 per km). The most important thing is to run at a conversational pace where you can speak in short sentences without gasping. As fitness improves over weeks and months, your natural pace will increase.