Fitness & Running Calculators
Train by the numbers — pace, heart-rate zones, splits and strength, all in one toolkit.
Updated June 2026 · Free · No sign-up
These calculators turn your goals, distances and body data into the numbers that actually shape a training plan. Runners can dial in a target with the Running Pace and Marathon Pace calculators — set a finish time and get your per-km pace, mile-by-mile splits and predicted 5K, 10K and half-marathon times. To train at the right intensity, the Target Heart Rate and Heart Rate Zone calculators map your five training zones using the max-HR and Karvonen (heart-rate reserve) methods.
On the strength side, the One Rep Max calculator estimates your 1RM from a lighter set using the Epley, Brzycki and Lander formulas, so you can program working weights without a risky max attempt. The Lean Body Mass calculator (Boer, James and Hume formulas) separates muscle from fat mass to track real body-composition changes. Treat the heart-rate figures as estimates — age-based max-HR formulas carry a wide margin — and check with a doctor before a hard training block if you have any cardiac history.
All Fitness & Running Calculators
Running Pace Calculator
Calculate running pace, finish time, and distance for any running event.
Marathon Pace Calculator
Calculate your goal marathon pace per mile/km, mile-by-mile splits, and predict 5K/10K/half marathon times from any pace or finish target.
Heart Rate Calculator
Calculate your target heart rate zones for maximum fat burn and cardio fitness.
Heart Rate Zones Calculator
Calculate your 5 heart rate training zones (recovery, fat burn, aerobic, anaerobic, max) using max-HR and Karvonen formulas based on age, resting HR, and fitness level.
One Rep Max Calculator
Calculate your one rep max for any lift using Epley, Brzycki, Lander, and other formulas.
Lean Body Mass Calculator
Calculate lean body mass and fat mass using the Boer, James, and Hume formulas.
Frequently asked questions
How do I calculate my target heart rate zones?
A common starting point is estimated maximum heart rate of about 220 minus your age, with training zones set as percentages of that maximum. The Karvonen method is more personalised because it also uses your resting heart rate (heart-rate reserve) to define each zone. These are estimates with a wide individual spread, so use them as a guide and pair them with how the effort actually feels.
What pace do I need to hit my marathon goal?
Goal pace is simply your target finish time divided by the distance — for example, a 4-hour marathon needs roughly a 5:41 per-km pace over 42.195 km. The Marathon Pace calculator also produces split times and predicts your shorter-distance times from that effort. Remember that race-day heat and humidity, common in much of India, can slow realistic pace versus a cool training run.
How accurate is a one rep max calculator?
One-rep-max formulas like Epley and Brzycki estimate your maximum from a set of multiple reps, and they are most accurate in the lower rep range (around 2–10 reps). Above roughly 10–12 reps the estimate drifts, because endurance and technique start to matter more than pure strength. Use it to set training loads safely rather than as an exact, attempt-it-today number.
What is lean body mass and why does it matter?
Lean body mass is your total weight minus fat mass — muscle, bone, organs and water. Tracking it alongside body weight shows whether changes on the scale are muscle or fat, which matters when you are cutting or bulking. The calculator estimates it from height, weight and sex using validated formulas, but methods like DEXA give a more precise body-composition reading.
Explore other calculator hubs
Loan & EMI Calculators
Every EMI, eligibility and prepayment tool for Indian borrowers — in one place.
Income Tax Calculators (FY 2026-27)
Plan your FY 2026-27 taxes — regime comparison, deductions, TDS and salary, all updated to the latest slabs.
Investment & Mutual Fund Calculators
Project your wealth — SIP, lumpsum, step-up, withdrawals and return metrics for Indian investors.
Savings & Deposit Calculators
Maturity and interest for every Indian savings scheme — government and bank.
Health & Fitness Calculators
Know your numbers — body composition, calories and macros, with Asian-Indian health cutoffs.
CGPA & Percentage Calculators
Convert CGPA, SGPA and marks to percentage using each board's official formula.
Insurance Premium Calculators
Estimate the premium for every policy — life, health and motor — before you buy.
Retirement & Pension Calculators
Plan the corpus and monthly pension you'll retire on — every Indian retirement tool in one place.
GST & Business Calculators
Run the numbers for your shop or business — GST, pricing, margins and returns.
Date & Time Calculators
Work out any date, duration or auspicious time — from your age to today's Panchang.
Stock Market & Trading Calculators
Every trade-cost, margin and options tool an Indian trader needs — in one place.
Money & Budgeting Calculators
Plan a budget, grow your savings and protect against inflation — all in one place.
Property, NRI & Forex Calculators
Property purchase, NRI remittance and forex transfers — costed for India in one place.
Pregnancy & Women's Health Calculators
Plan your cycle and pregnancy — ovulation, due dates and healthy weight gain in one place.
Diet & Body Metrics Calculators
Know your body's numbers — macros, hydration, fasting windows and key health markers.
Statistics & Probability Calculators
From averages to p-values — descriptive stats, probability and inference made simple.
Geometry Calculators
Solve area, volume, triangles and circles with the correct formula every time.
Algebra & Numbers Calculators
Solve percentages, fractions, quadratics, exponents and factors with full steps.
Math Tools & Converters
Everyday tools: a scientific calculator, unit converter, number-base and matrix maths.
Science & Engineering Calculators
Solve physics, chemistry and electronics with Ohm's law, half-life and molarity.
Exams & Admissions Calculators (India)
Predict your rank, band and score — and cost a degree abroad — all in one place.
Vehicle & Travel Calculators
Work out what your car really costs to buy and run — on-road price, fuel and EV charging.
Home & Energy Calculators
Get a grip on your power bill — estimate electricity costs, AC running and solar savings.
Construction & DIY Calculators
Estimate materials before you buy — concrete, tiles, roofing and Indian land units.
Everyday Tools & Fun Calculators
Quick everyday helpers and a few just-for-fun tools, from bill splits to pet ages.