Running Calculators for Better Training and Race Decisions
Turn pace, race times, VO2max, training zones, fueling, recovery, and gear data into practical next steps.
Start With The Decision You Need To Make
Race Planning
Goal times, pacing strategy, splits, and realistic finish predictions.
Race Time Predictor
Expected finish time for any race distance. Know your 5K? Predict marathon, half or 10K in seconds. …
Running Pace Calculator
Free running pace calculator. Converts between pace (min/km, min/mile), speed (km/h, mph), and finish …
Marathon Pace Calculator
Set a 26.2 mile goal time and instantly see your required pace per mile and per km, with key checkpoint …
Half Marathon Pace Calculator
Plan your 13.1 mile race with a target finish time. Get per-mile and per-km paces plus every mile split. …
Negative Split Calculator
Plan your race splits with a negative or even split strategy. Calculate first and second half paces to …
Track Split Calculator
Calculate your 200m and 400m lap splits needed to hit your target race time on a standard 400m track. …
Training Intensity
Use recent performance and physiology signals to choose smarter workout intensity.
Training Zone Calculator
Calculate your personalized running training zones from any race performance. Get Easy, Marathon, …
Threshold Pace Calculator
Calculate your lactate threshold pace from recent race times. Find the exact pace for tempo runs to …
Easy Run Pace Calculator
Calculate your recovery and easy run pace from a recent race result. Ensure you're training at the right …
VO2max Calculator
Estimate your VO2max from running performance, resting heart rate, or fitness tests. Free online aerobic …
Heart Rate Drift Calculator
Estimate cardiac drift during long runs. Calculate how much your heart rate rises at the same pace over …
Training Load Calculator
Calculate your training load, acute:chronic workload ratio (ACWR), and injury risk using TSS, distance, …
Marathon, Fueling, And Hydration
Plan the work and the intake needed to make long races less fragile.
Race Fuel Calculator
Calculate exactly how many gels, chews, or carbs you need during a race based on your finish time, body …
Race Day Nutrition Calculator
Plan your complete race day nutrition including pre-race carb loading and in-race fueling. Personalized …
Running Hydration Calculator
Calculate your fluid needs for running based on sweat rate, temperature, humidity, and duration. Prevent …
Marathon Wall Calculator
Predict when you'll hit the wall in a marathon based on your glycogen stores, pace, and body weight. Plan …
Ultra Marathon Pace Calculator
Calculate pacing strategies for 50K, 50 mile, 100K, and 100 mile ultramarathons. Includes aid station …
Mechanics, Treadmill, And Gear
Translate running form, treadmill settings, and shoe wear into practical choices.
Running Cadence Calculator
Find your optimal running cadence (steps per minute) based on your height and pace. Improve efficiency …
Running Stride Length Calculator
Calculate your running stride length from pace and cadence. Understand how stride length and cadence …
Running Economy Calculator
Calculate your running economy — oxygen cost per km — from your VO2max and current pace. Understand how …
Running Power Calculator
Estimate your running power output in watts from pace, body weight, and terrain grade. Based on Minetti's …
Treadmill Pace Converter
Convert treadmill speed (mph or km/h) to running pace (min/km or min/mile). Includes incline adjustment …
Running Shoe Mileage Tracker
Find out when to replace your running shoes based on current mileage, weekly usage, and shoe type. …
Built Around The Runner's Next Question
Interpret the result
A number is not enough. Priority calculators are being upgraded to explain what the output means in training or racing terms.
Compare realistic options
Race goals, pacing choices, and training zones should be compared against recent performance, not guessed in isolation.
Choose the next action
Each calculator should point to the next useful decision: training pace, race prediction, fueling, recovery, or gear timing.
Stay fast and focused
The core experience remains lightweight, static, and free. Deeper product features will be added only where they improve decisions.
Make Better Running Decisions
RunCalc is being rebuilt around one clear purpose: helping runners and endurance athletes make better decisions.
The calculators are only the starting point. A useful result should help you understand what it means, compare realistic options, choose the next workout or race goal, and avoid common training mistakes.
What RunCalc Focuses On Now
- Race planning: goal times, race predictors, pacing, negative splits, track splits, and Boston qualifying context.
- Training intensity: easy pace, threshold pace, VO2max, heart-rate drift, and training zones.
- Marathon preparation: marathon pace, wall-risk thinking, fueling, hydration, and race-day execution.
- Running mechanics: cadence, stride length, running economy, power, treadmill conversion, and shoe mileage.
- Recovery and load: recovery timing, training load, and decisions about when to push or back off.
The Product Standard
Every priority running calculator should eventually answer four questions:
- What is my result?
- What does it mean for my current fitness or goal?
- What should I do next?
- Which related decision should I make after this?
Some older calculators remain available while the site is repositioned, but the product direction is running and endurance first.