Introduction
Whether you're training for your first 5K or chasing a marathon PR, knowing your pace is key to running smarter. This free Pace Calculator lets you quickly find your pace, finish time, or distance — just enter two values, and it solves for the third. It works for miles and kilometers, so you can use whichever unit you prefer.
Beyond basic pace math, this tool includes a split table generator that breaks your run into even or negative splits, a race time predictor that uses the proven Riegel formula to estimate your finish time at other distances, and a training pace zone guide that shows you exactly how fast to run for easy days, tempo runs, and interval workouts. There's also a built-in pace and speed converter so you can switch between minutes per mile, minutes per kilometer, miles per hour, and more in seconds. Whether you're planning race day strategy or building a weekly training schedule, this calculator gives you everything you need in one place.
How to Use Our Pace Calculator
Enter your running time, distance, or pace, and this calculator will solve for the missing value. It also gives you split times, race predictions, training zones, and pace conversions.
Solve Mode: Choose what you want to find — Pace, Time, or Distance. The calculator will figure out the missing piece based on the other two values you provide.
Unit System: Select US (miles) or Metric (kilometers) to set your preferred units for distance and pace across the calculator.
Time: Enter your total running time in hours, minutes, and seconds (HH:MM:SS). For example, type 0:25:00 for a 25-minute run.
Distance: Type in how far you ran or plan to run, and pick a unit like miles, kilometers, meters, or yards. You can also choose a common race event from the dropdown, such as 5K, 10K, half marathon, or marathon, to fill in the distance automatically.
Pace / Speed: Select a pace format like minutes per mile, minutes per kilometer, miles per hour, or kilometers per hour. Then enter your pace as a time (MM:SS) or as a speed number, depending on the format you chose. If you need to convert between different speed and pace formats, you can also use our Speed Calculator for quick reference.
Splits Tab: Set a split interval (such as every 1 km or 1 mile) and adjust the negative split slider to simulate running the second half faster or slower. Click "Generate Splits" to see a table and chart of each segment's time and pace.
Race Predictor Tab: Pick a race distance you have already completed and enter your finish time. The calculator uses the Riegel formula to predict your finish times for other distances, from 800 meters up to 50K. It also shows how your pace compares to world records.
Training Paces Tab: Click "Calculate Training Paces" to see five recommended training zones — Easy, Long Run, Tempo, Interval, and Repetition — based on your most recent calculated pace. Each zone shows a pace range in minutes per kilometer. For a deeper dive into effort-based training, check out our RPE Calculator and Heart Rate Zone Calculator.
Converter Tab: Enter a pace in minutes and seconds per kilometer, then click "Convert" to instantly see that pace expressed in eight different formats, including minutes per mile, kilometers per hour, miles per hour, meters per second, and more.
What Is Running Pace and Why Does It Matter?
Running pace is the amount of time it takes you to cover a set distance, usually shown as minutes per mile or minutes per kilometer. For example, if you run one mile in 8 minutes, your pace is 8:00 per mile. Pace is one of the most important numbers for any runner because it helps you plan your races, track your progress, and train at the right effort level.
How Pace, Time, and Distance Are Connected
Pace, time, and distance are linked by a simple relationship: if you know any two of them, you can figure out the third. If you know your pace and your distance, you can find your finish time. If you know your finish time and distance, you can find your pace. And if you know your pace and time, you can find how far you ran. This calculator lets you pick which value you want to solve for and does the math for you. For a more detailed look at the underlying math, our Distance Calculator can help you work with distance-related formulas in other contexts.
Understanding Speed vs. Pace
Pace and speed measure the same thing but in opposite ways. Pace tells you how long it takes to go one unit of distance (like 5 minutes per kilometer). Speed tells you how much distance you cover in one unit of time (like 12 kilometers per hour). Runners usually talk in pace, while cyclists and drivers usually talk in speed. A faster runner has a lower pace number but a higher speed number.
Splits and Negative Splits
A split is the time it takes to complete one segment of your run, like each mile or each kilometer. Tracking your splits shows whether you sped up or slowed down during a run. A negative split means you ran the second half faster than the first half. Many coaches recommend this strategy because it helps you avoid going out too fast and running out of energy before the finish line. A positive split is the opposite — starting fast and slowing down — which is common but usually less efficient.
The Race Predictor and the Riegel Formula
The race predictor tab uses the Riegel formula, a well-known equation created by researcher Peter Riegel. It estimates your finish time for a new race distance based on a time you already ran at a different distance. The formula is: T2 = T1 × (D2 ÷ D1)1.06. The exponent of 1.06 accounts for the fact that you naturally slow down a little as the distance gets longer. This prediction works best for distances between 1,500 meters and the marathon. For ultramarathons (50K and beyond), real-world times tend to be slower than the formula predicts because fatigue, terrain, and fueling play a bigger role. For an alternative approach to predicting your race fitness, you can also explore our VDOT Calculator, which uses Jack Daniels' training methodology, or check your aerobic capacity with a VO2 Max Calculator.
Training Pace Zones
Not every run should be done at the same speed. Good training plans use different pace zones, each with a specific purpose:
- Easy / Recovery: A slow, comfortable pace where you can hold a full conversation. This builds your aerobic base and helps your body recover between hard workouts. Most of your weekly mileage should be at this effort.
- Long Run: Slightly faster than easy pace, held for extended periods to build endurance.
- Tempo / Threshold: A "comfortably hard" pace you could hold for about 30 to 60 minutes. It trains your body to clear lactic acid more efficiently.
- Interval / VO2max: Hard efforts lasting 3 to 5 minutes with rest in between. This improves your body's ability to use oxygen.
- Repetition / Speed: Very short, fast bursts that improve your running form and economy.
To fuel your training properly across these zones, consider using a Calorie Calculator or Macro Calculator to dial in your nutrition. You can also estimate the energy you burn during workouts with our Calories Burned Calculator.
Common Race Distances
Road races come in standard distances. The most popular ones are the 5K (3.1 miles), 10K (6.2 miles), half marathon (13.1 miles), and marathon (26.2 miles). Track events include the 800 meters, 1,500 meters, and 3,200 meters. Ultramarathons start at 50K and go up to 100 miles or more. Knowing these distances helps you set pace goals and compare your fitness across different race types. For race-specific pacing strategies, try our dedicated 5K Pace Calculator, Half Marathon Pace Calculator, or Marathon Pace Calculator. If you're also a swimmer looking for a similar tool, our Swimming Pace Calculator works the same way for the pool.
Tips for Using a Pace Calculator
When using this tool, enter realistic numbers based on recent runs or races. If you have not raced lately, use a hard training run as your starting point. Keep in mind that predicted times assume flat terrain, good weather, and proper rest. Hills, wind, heat, and altitude will all slow you down. Use the training paces as guidelines, not strict rules — listen to your body and adjust as needed. Staying properly hydrated also matters; our Water Intake Calculator can help you plan your fluid needs, and a BSA Calculator can give you a better sense of your body's surface area for estimating sweat loss. If cycling is part of your cross-training, the Bike Gear Ratio Calculator can help you optimize your rides as well.