Run Race Pace Calculator
Calculate running pace per mile and per kilometer from race distance and finish time, then project that pace to 5K, 10K, half marathon, or marathon distance.
Interactive calculatorOpen calculatorSports Calculators
13 interactive calculators · 0 planning guides
Explore pace, motion, and sizing calculations with explicit assumptions and limits.
Availability
Use listed tools as planning aids and read each page's formula, example, assumptions, and limits.
Start here paths
Choose the sports or hobby decision
Start with the question you are trying to answer, then open the calculator that matches the distance, split, or sizing decision.
Plan race pace
Calculate running pace per mile and per kilometer from race distance and finish time, then project that pace to 5K, 10K, half marathon, or marathon distance.
Interactive calculatorChoose ski length
See beginner height ranges for classic/skate, then check the exact ski bodyweight and flex chart. No generic backcountry size is calculated.
Interactive calculatorEstimate jump airtime or height
Convert measured airtime to estimated vertical rise and takeoff speed, or enter vertical takeoff speed to estimate airtime using same-height projectile motion.
Interactive calculatorRunning calculators
Jump airtime
Ski sizing
Complete shelf
All sports calculators
13 calculators and planning guides are available. 13 offer interactive results; every page explains its assumptions, scope, and limitations. Use the details on each page to choose the tool that fits your question.
Hang Time Calculator
Convert measured airtime to estimated vertical rise and takeoff speed, or enter vertical takeoff speed to estimate airtime using same-height projectile motion.
Interactive calculatorOpen calculatorCross Country Ski Size Calculator
See beginner height ranges for classic/skate, then check the exact ski bodyweight and flex chart. No generic backcountry size is calculated.
Interactive calculatorOpen calculatorSwim Pace Calculator
Calculate swim pace per 25, 50, and 100 yards or meters, speed, pool lengths, and projected splits from distance, time, units, and course length.
Interactive calculatorOpen calculatorArrow Weight Calculator
Add up total arrow weight in grains and grams from shaft length and GPI, point, insert, nock, fletching and wrap, with optional grains per pound of draw weight.
Interactive calculatorOpen calculatorEngine Displacement Calculator
Work out engine displacement from bore, stroke and cylinder count in cc, liters and cubic inches, plus static compression ratio from chamber volume.
Interactive calculatorOpen calculatorHiking Time Calculator
Estimate hiking time from distance, ascent and descent using Naismith-style rules you can edit, plus break time, total time and a planning range.
Interactive calculatorOpen calculatorOne Rep Max Calculator
Estimate a one-rep max for deadlift, squat or bench from weight and reps with five published formulas, their average, and a 50–95% percentage table.
Interactive calculatorOpen calculatorProp Slip Calculator
Calculate boat propeller slip from engine RPM, gear ratio, prop pitch and measured speed in mph or knots, with theoretical no-slip speed and prop shaft RPM.
Interactive calculatorOpen calculatorSlugging Percentage Calculator
Calculate slugging percentage (SLG) from singles, doubles, triples and home runs, plus total bases, batting average, ISO, on-base percentage and OPS.
Interactive calculatorOpen calculatorTire Size Calculator
Compare two tire sizes by width, aspect ratio and rim diameter: sidewall, overall diameter, circumference, revolutions per mile and speedometer error.
Interactive calculatorOpen calculatorTriathlon Calculator
Project triathlon swim, bike and run splits and a finish time from your paces and transition times for sprint, Olympic, 70.3, full or custom distances.
Interactive calculatorOpen calculatorGolf Course & Playing Handicap Calculator
Convert an established Handicap Index into an 18-hole Course Handicap and Playing Handicap using entered ratings, par and allowance with plus-handicap support.
Interactive calculatorOpen calculatorMethodology notes
- Jump airtime uses constant-gravity vertical motion and requires matching takeoff and landing height for the symmetric result.
- Running pace uses time divided by distance and shows both mile and kilometer pace.
- Sports sizing tools are starting points; manufacturer charts, race conditions, terrain, and personal fit can override a general result.
- Each tool includes examples, limits, and source notes so you can compare the result with event conditions and manufacturer guidance.