Science-Based Calculator for Every Runner
From Riegel Predictions to Karvonen HR Zones and Pace Conversion.
1) Race Goal & Pace Prediction
Enter a recent race time to predict your finish time for a target race using the Riegel formula. You can also set a goal time manually to see the required pace.
My Recent Race (Baseline)
Target Race
Predicted/Goal Time
โ
Required Pace
โ min/km
| 1k | 5k | 10k | 20k | Half | 30k | 40k | Finish |
|---|
2) Heart Rate Zones & MAF Calculator
A. Maffetone 180 Formula (MAF HR)
My Max Aerobic Function HR (MAF HR)
โ bpm
During aerobic training, aim to stay within your MAF HR (typically MAF HR - 10 to MAF HR).
B. Standard Heart Rate Zones (Zone 2)
Zone 2 (Selected Range)
โ bpm
โ
Calculated MAX HR
โ bpm
| Zone | Range (%) | BPM Range |
|---|---|---|
| Please enter your info | ||
3) Pace & Treadmill Speed Converter
โก๏ธ 400m Lap Time for Track Workouts
400m Lap Time
โ sec
๐โโ๏ธ Running Gear Guide
The right gear plays a crucial role in performance and injury prevention. Here are top recommendations reflecting the 2024-2025 lineup.
๐ Choosing Running Shoes
- โข Fit: Choose a width (last) that matches your foot.
- โข Cushion: Varies by weight, distance, and purpose (recovery vs. racing).
- โข Drop: Heel-to-toe offset (4โ10mm is common).
- โข Weight: Lightweight racers (โ200gโ) vs. daily trainers (โ240โ300g).
โ Choosing a Running Watch
- โข GPS Accuracy: Dual-band for reliability in cities/tracks.
- โข HR/HRV: Monitor training load and recovery.
- โข Battery Life: Essential for long runs and ultras.
- โข Metrics/Maps: VO2 Max, Training Readiness, built-in maps.
๐ก Top Gear Picks (2024โ2025)
Concise recommendations for every level, from beginner to advanced.
๐ Running Shoes
Beginner (Daily Trainer): Nike Pegasus 41, ASICS Novablast 4
Intermediate (Tempo/Long Run): Hoka Mach 6, Saucony Endorphin Speed 4
Advanced (Racing Super Shoes): Nike Alphafly 3, Adidas Adizero Adios Pro 4
โ Running Watches
Entry-Level: Garmin Forerunner 165, Coros Pace 3
Mid-Range: Garmin Forerunner 265 (AMOLED, Training Readiness)
High-End: Garmin Forerunner 965 (Maps, Multi-Band), Apple Watch Ultra 2
๐ Advanced Running Concepts
๐โโ๏ธ Zone 2 Training: Get Faster by Going Slower
Zone 2 training is one of the most important concepts in modern endurance science. Often called a "conversational pace," it's the optimal intensity for your body to prioritize fat over carbohydrates as its primary energy source, building a strong aerobic base.
๐ฉบ The Maffetone Method and 180 Formula
Developed by Dr. Phil Maffetone, this method focuses on maximizing aerobic fitness without injury. The core principle is to train at or below your Maximum Aerobic Function (MAF) heart rate.
Calculating MAF Heart Rate: The 180 Formula
Base Formula: 180 - Your Age
Then, modify this number based on your health profile:
- Subtract 10: Recovering from major surgery or illness.
- Subtract 5: Prone to injuries, frequent colds, or have asthma/allergies.
- No change: Training consistently for up to two years without issues.
- Add 5: A competitive athlete training for more than two years with improving performance.
For example, a 35-year-old who has been training consistently would have a MAF HR of 180 - 35 = 145 bpm. The training range would be between 135 and 145 bpm. The calculator above automates this process.
๐ HR-Based Training: Karvonen vs. %Max HR
Setting the right training zones is key. Here are the two main methods:
%Max HR Method
A simple method based only on your maximum heart rate.
Karvonen (HRR) Method
A more personalized method that accounts for your Resting Heart Rate (RHR), reflecting your current fitness level. Formula: Target HR = ((Max HR - RHR) ร % Intensity) + RHR.
๐ Riegel's Prediction Model: Scientific Race Planning
The Riegel formula is a widely used model to predict race times. It's an empirical formula that estimates a performance at one distance based on a recent result at another.
The Riegel Formula
Formula: Tโ = Tโ ร (Dโ/Dโ)ยนยทโฐโถ