DIY Sports Drink Calculator
Commercial sports drinks are formulated around two key numbers — carbohydrate concentration and sodium concentration — and both can be replicated fairly closely at home with plain sugar, table salt, and water for a fraction of the cost. This calculator…
Fish Weight Calculator
Weighing a fish on an actual scale, especially a big one intended for release, isn’t always practical or good for the fish’s health, which is exactly why anglers have long relied on a simple length-and-girth formula to estimate weight…
Hull Speed Calculator
Every displacement-hull boat — from a small sailing dinghy to a large trawler — has a theoretical maximum efficient speed determined almost entirely by its waterline length, a limit boat designers and sailors call “hull speed.” This…
Swim Time Converter
Competitive swimming is contested in three distinct pool configurations — short course yards (25-yard pools, standard in US college and high school swimming), short course meters (25-meter pools), and long course meters (50-meter pools, the Olympic…
5/3/1 Calculator
Jim Wendler’s 5/3/1 program is one of the most enduringly popular structured strength training systems, built around a deliberately conservative “training max” and a repeating three-week percentage wave rather than chasing a true 1-rep…
Target Heart Rate Calculator
Target heart rate tells you the beats-per-minute range to aim for during a workout to hit a specific training intensity. This calculator uses the Karvonen method, which factors in your resting heart rate alongside your estimated max heart rate — a more…
VO2 Max Calculator – Aerobic Capacity
VO2 max — the maximum volume of oxygen your body can use during intense exercise, measured in milliliters per kilogram of body weight per minute — is considered the gold-standard measure of aerobic fitness. This calculator uses the Cooper test, a simple…
Marathon Pace Calculator
Marathon pace calculation tells you the exact per-kilometer and per-mile speed you need to sustain for 26.2 miles (42.195 km) to hit a specific goal finish time. Unlike a general running pace calculator, this tool is built specifically around marathon…
Race Predictor – Running Time Calculator
A race predictor takes one recent race result and projects what you could realistically run at other distances, using a mathematical relationship between distance and endurance-adjusted pace. It’s built on the Riegel formula, one of the most widely…
Race Time Improvement Calculator
Comparing two race times directly in minutes and seconds tells you how much time you saved, but it doesn’t tell you how meaningful that improvement actually was — a 90-second improvement means something very different for a 15-minute 5K than it…