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- BMI Calculator
- TDEE Calculator
- BMR Calculator (Mifflin-St Jeor)
- Reference Weight Formulas
- Waist-to-Hip Ratio Calculator
- Height Converter (cm to feet/inches)
- Weight Converter (kg to lbs)
- Distance Converter (km to miles)
- Speed Converter (MPH to km/h to m/s)
- Grade to Degrees Converter
- FTP Calculator (from 20-Min Test)
- Cycling Power Zones Calculator
- Cycling Power Calculator (Watts from Speed)
- Power-to-Weight Ratio Calculator
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- Steps to Calories
- Calorie Burn — Running
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- Calorie Burn — HIIT & Circuit Training
- Max Heart Rate Calculator (220 Minus Age)
- Target Heart Rate Calculator
- Heart Rate Zones (Karvonen Method)
- Heart Rate Zones (% of Max)
- Max Heart Rate Comparison Calculator (4 Formulas)
- Calorie Deficit Planner
- Macro Split Calculator
- Protein Intake Calculator
- Water Intake Calculator
- Caffeine Half-Life Calculator
- Time-to-Goal Calculator (Weight)
- Weight Change Percentage Calculator
- Strength Progression Calculator
- Training Cycle Planner (Weeks/Deload)
- Personal Record Progression Calculator
- Running Pace Calculator
- Beep Test (20 m Shuttle Run)
- Cooper 12-Minute Run Test
- VDOT Calculator (Jack Daniels)
- Marathon Time Predictor
- One-Rep Max Calculator (Epley Formula)
- Barbell Plate Calculator (lbs)
- Strength Standards Percentile Calculator
- Barbell Plate Calculator (kg)
- Wilks Score Calculator
Reading
From the blog
Running
The Riegel Formula: Predicting Race Times
The Riegel formula scales a known race time to any other distance using one fitted exponent of 1.06. Here is where that number came from, how to work the arithmetic by hand, and the distances at which the estimate starts to drift.
12 min read
Running
How to Predict Marathon Time
A half marathon in 1:45:00 does not double into a 3:30:00 marathon. This guide works through how to predict marathon time with the Riegel formula, step by step, and shows where the estimate runs faster than the day itself.
13 min read
Running
What Is VDOT? The Jack Daniels Formula Explained
VDOT turns one race result into a single running fitness score on the VO2max scale. This guide sets out both Daniels–Gilbert equations in full, works a 45:00 ten kilometre through to 45.3 step by step, and marks the durations where the model quietly stops meaning what it says.
12 min read