⏱
Select Your Goal
Choose Find Pace, Find Time, or Find Distance. Race preset chips fill the distance instantly.
📈
Input Your Metrics
Enter your known data. Toggle between Miles and Kilometers — values convert automatically.
🏆
Analyze & Plan
Review pace, race predictions, training zones, and per-mile splits. Use the Race Planner and Training Zones tabs for deeper analysis.
PaceTime required to cover one distance unit (min/mi or min/km). Lower = faster. Negative SplitRunning the second half faster than the first. Nearly all world records use this strategy. VO2maxMaximum oxygen consumption during exercise (ml/kg/min). Key indicator of aerobic fitness. CadenceSteps per minute. Elite runners typically maintain 170–190 spm. Training ZonesFive pace ranges: Easy, Tempo, Race, Interval, Sprint — each targeting different physiological adaptations. BQ (Boston Qualifier)A marathon time meeting the BAA qualifying standard. Varies by age and gender. 5K Pace
Given: 5K in 25:00.
Pace = 25:00 ÷ 3.107 mi = 8:03/mi
Speed = 60 ÷ 8.05 = 7.45 mph
Marathon Splits
Goal: 4:00:00 marathon.
Even pace = 9:10/mi
Negative: 1st half 2:02, 2nd half 1:58
Calorie Burn
Given: 160 lb, 8:00/mi, 45 min.
MET ~10.5, Calories = 10.5 × 72.6 × 0.75 = 572 kcal
How to Use This Calculator
1
Enter Known Values
Input any two of: distance, time, and pace to calculate the third.
2
Choose Units
Select miles or kilometers and min/mile or min/km for pace.
3
View Split Table
See projected split times for common race distances.
Key Terms
- Pace
- The time per unit distance (e.g., 8:30 per mile). The inverse of speed for runners.
- Negative Split
- Running the second half of a race faster than the first. Associated with better race outcomes.
- Splits
- Time checkpoints at regular intervals (each mile or kilometer) during a run.
- Race Pace
- The target pace for a specific race distance, accounting for distance-appropriate effort level.
Real-World Examples
Example 1
5K Runner
Distance: 5K (3.1 mi), Time: 25:00
Result: Pace = 8:03/mile (5:00/km). Projected 10K time: ~52:00 at same effort.
Example 2
Marathon Pacer
Target: sub-4:00 marathon, Distance: 26.2 miles
Result: Required pace = 9:09/mile. Half marathon split target: 1:59:30.
Understanding Running Pace
Pace vs. Speed
Runners think in pace (minutes per mile) rather than speed (miles per hour). An 8:00/mile pace equals 7.5 mph. Pace is more intuitive for training because small differences in pace have large effects on race times.
Finding Your Race Pace
Your easy/training pace should be 1-2 minutes per mile slower than race pace. If you can hold a conversation, you are in the right zone. Race pace should feel controlled but challenging — not an all-out sprint.
The Pace-Distance Relationship
As distance doubles, pace typically slows 5-10%. A 20:00 5K runner might run a 42:00 10K and a 1:35 half marathon. The slowdown increases with distance due to fuel depletion and fatigue.
Frequently Asked Questions
What is a good running pace for beginners?
Most beginners comfortably run at 10:00-13:00 minutes per mile (6:15-8:00 per km). The best pace for a new runner is one where you can hold a conversation without gasping. Starting too fast is the most common beginner mistake and leads to burnout or injury. Focus on completing the distance first, then gradually increase speed over weeks and months.
What is the difference between pace and speed?
Pace is time per unit distance (e.g., 8:00 min/mile), which is the standard metric used by runners. Speed is distance per unit time (e.g., 7.5 mph), which is what treadmills display. They are inversely related: faster speed means lower pace numbers. Runners prefer pace because it directly translates to race planning and split calculations.
What is a negative split and why is it recommended?
A negative split means running the second half of a race faster than the first half. This strategy is considered optimal because it prevents early glycogen depletion and allows your body to warm up progressively. Most marathon world records have been set with negative or even splits. Starting conservatively and building speed requires discipline but typically produces faster overall finish times.
How much slower should my training pace be compared to race pace?
Easy training runs should be 60-90 seconds per mile slower than your current 5K race pace. Most runners make the mistake of running easy days too fast, which compromises recovery and limits the aerobic benefits of easy running. The 80/20 rule suggests 80% of your weekly mileage should be at an easy, conversational pace, with only 20% at moderate or hard effort.
How do altitude and heat affect running pace?
At 5,000 feet elevation, expect paces to slow by 15-30 seconds per mile due to reduced oxygen availability. Heat has an even greater effect: for every 10 degrees Fahrenheit above 55F, pace slows by approximately 1.5-3% as your body diverts blood to the skin for cooling. Adjust your target pace downward in hot or high-altitude conditions rather than trying to force your usual speed.