Pace Calculator – Hit Your Race Splits
Calculate your exact pace for any distance—from 5K to Ultramarathon. Convert between min/mile and min/km instantly to lock in your race day strategy.
Run Details
Your Pace
Speed
In running, "Speed" is vanity, but Pace is sanity. Experienced runners don't track speed (mph); they track splits (minutes per mile).
This calculator allows you to reverse-engineer your goals. If you want to break 4 hours in the marathon, you don't just "run fast"—you need to hold exactly 9:09/mile for 26.2 miles. This tool does that math for you.
The "Banked Time" Myth
Novice runners often run fast early to "bank time" for later. This almost always fails due to glycogen depletion. Our tool helps you calculate an Even Split pace, which is statistically the most efficient way to race.
Treadmill Conversions
Gym treadmills usually show MPH or KM/H. If your training plan calls for an 8:00 pace, do you know what speed setting that is? (Hint: It's 7.5 MPH). This tool bridges that gap.
Understanding Lactate Threshold
Your pacing strategy should change based on the distance. The shorter the race, the higher percentage of your VO2 Max you can sustain.
The "Wall" Math
The human body stores about 2,000 calories of glycogen. Pacing isn't just about speed; it's about fuel economy.
Running 30 seconds per mile too fast in the first half of a marathon burns glycogen at an exponential rate, ensuring you hit "The Wall" at mile 20. Sticking to your calculated pace preserves those critical carbohydrate stores.
Pro Strategy: The Negative Split
Finish Stronger Than You Start
Every world record set in distance running in the last 20 years has been run with a Negative Split—meaning the second half was faster than the first.
- Warm Up (Miles 1-3):Run 10-15 seconds SLOWER than your goal pace. Let your body temperature rise naturally without spiking heart rate.
- Cruising Altitude (Middle):Lock into goal pace. This should feel "comfortably hard".
- The Kick (Last 20%):Unleash your reserve energy. Pass the runners who started too fast.
The Physics of Running
Pace is simply the inverse of speed. While speed measures distance per unit of time (km/h), pace measures time per unit of distance (min/km).
To calculate accurate splits, we convert all inputs into total seconds. For example, a 4-hour marathon is 14,400 seconds divided by 26.2188 miles, resulting in 549 seconds per mile, which converts to 9 minutes and 9 seconds per mile.
Marathon Goals: Speed vs. Endurance
Just Finish
Target Time: 4:30 - 5:00 hrs
Pace: 10:18 - 11:27 / mile
Strategy: Run/Walk method. Keep HR in Zone 2.
Focus on fueling and hydration, not the clock.
Sub-4 Hour
Target Time: 3:59:59
Pace: 9:09 / mile
Strategy: Even splits. Don't start faster than 9:00 pace.
Requires consistent weekly mileage (30-40 miles/week).
Boston Qualifier
Target Time: 3:00:00 (Men <35)
Pace: 6:52 / mile
Strategy: Aggressive but controlled. Threshold training essential.
Optimization of diet, gear, and sleep is required.
Related Tools
Why does my GPS watch say I ran farther?
GPS watches are generally accurate to +/- 1%. However, race courses are measured via the 'shortest possible tangent' line. Since you likely weave around other runners and don't run perfect tangents, you will almost always run 26.4 or 26.5 miles in a marathon. Account for this 'GPS Tax' by training to run 5-10 seconds faster per mile than the official math suggests.
How much does wind affect pace?
A tailwind helps you less than a headwind hurts you. A 10mph headwind can cost you 10-15 seconds per mile, while a 10mph tailwind might only gain you 5-6 seconds. Effort is key throughout.
Can I use this for swimming or cycling?
Yes. Pace is universal. For swimming (min/100m) or cycling (mph), simply adjust your distance expectations. 20mph on a bike is roughly equivalent to a 3:00/km run pace in terms of metabolic output.
What is a 'BQ' time?
BQ stands for Boston Qualifier. It is the holy grail for amateur runners. For a man under 35, the standard is 3:00:00. This requires a 6:52/mile pace or faster.
How do hills affect pace strategy?
On uphills, maintain EFFORT, not pace. If you try to hold 8:00 pace up a steep hill, you will burn matches you need later. Slow down on the ups, and use gravity to recover speed on the downs.
Running Terminology
Split
The time taken to complete a specific segment of the run (usually 1 mile or 1 km).
Cadence
Steps per minute. Efficient runners typically aim for 170-180 steps per minute to minimize impact forces.
Bonk
Also known as "Hitting the Wall". The sudden fatigue experienced when glycogen stores are fully depleted.
Tempo Run
A sustained run at "Threshold Pace" (comfortably hard). It trains the body to clear lactate efficiently.
About This Calculator
Our Pace Calculator uses standard kinematic equations without rounding errors. It is calibrated to official World Athletics distance standards (e.g., a Marathon is exactly 42.195 kilometers). We double-check all conversions between imperial and metric systems to ensure millimeter-level precision.