AFT Calculator

AFT Calculator is a fast, accurate fitness calculator that helps you estimate training thresholds and build personalized heart rate zones. Designed for runners, cyclists, and everyday fitness users, it turns simple inputs into clear, actionable numbers you can use right away. Ideal for planning workouts, tracking progress, and optimizing performance in one lightweight Health and Fitness utility. Core features - Threshold and heart rate zone calculator using proven methods and sport types for running and cycling - Quick tools for VO2max estimation, pace and speed conversion, and calorie burn planning - Save, compare, and export results to streamline your training plan Keywords: fitness calculator, heart rate zones, training zones, VO2max, health and fitness app, running, cycling