# Captain Calc

> Free online calculators for math, science, percentages, area, and everyday problems. Fast, accurate, and easy to use — no signup required.

Every tool and article on Captain Calc is free to use — no sign-up required. The links below are the primary, canonical resources on this site.

## Tools

- [Mortgage Calculator](https://captaincalc.com/calculator/mortgage-calculator/): Calculate monthly mortgage payments, total interest, and amortization schedule. Free mortgage calculator with extra payment options.
- [Auto Loan Calculator](https://captaincalc.com/calculator/auto-loan-calculator/): Estimate your monthly auto loan payment based on loan amount, interest rate, and term. Compare new vs used car financing options.
- [401(k) Calculator](https://captaincalc.com/calculator/401k-calculator/): Project your 401(k) retirement savings with employer match, contribution limits, and compound growth over time.
- [Tip Calculator](https://captaincalc.com/calculator/tip-calculator/): Calculate tips instantly for restaurants, delivery, and services. Split bills between groups with custom tip percentages.
- [Percentage Calculator](https://captaincalc.com/calculator/percentage-calculator/): Find percentages quickly — calculate X% of Y, percentage change, and percentage difference between numbers.
- [Currency Converter](https://captaincalc.com/calculator/currency-converter/): Convert between 170+ world currencies using live exchange rates. See historical rates and conversion charts.
- [Unit Converter](https://captaincalc.com/calculator/unit-converter/): Convert between length, weight, temperature, volume, area, speed, and data storage units with precision.
- [Date Calculator](https://captaincalc.com/calculator/date-calculator/): Calculate days between dates, add or subtract days, find business days, and plan deadlines with our date calculator.
- [Discount Calculator](https://captaincalc.com/calculator/discount-calculator/): Calculate sale prices, savings amounts, and final costs after discount. Compare multiple discount offers side by side.
- [BMI Calculator](https://captaincalc.com/calculator/bmi-calculator-2/): Free BMI Calculator — enter height and weight to get your Body Mass Index, category (underweight to obese), and a color-coded range indicator instant…
- [Body Fat Percentage Estimator](https://captaincalc.com/calculator/body-fat-percentage-calculator/): Use the U.S. Navy tape-measure method to estimate body fat percentage from neck, waist, hip, and height — for men and women, with instant results.
- [Daily Calorie Needs (TDEE) Calculator](https://captaincalc.com/calculator/tdee-calorie-calculator/): Calculate your TDEE and daily calorie needs using the Mifflin-St Jeor formula. Get cutting, maintenance, and bulking targets based on your activity l…
- [BMR Calculator](https://captaincalc.com/calculator/bmr-calculator/): Calculate your Basal Metabolic Rate (BMR) using the Mifflin-St Jeor equation. Find daily calorie needs based on age, weight, height, and activity lev…
- [Ideal Body Weight Calculator](https://captaincalc.com/calculator/ideal-body-weight-calculator/): Calculate your ideal body weight using the Devine, Robinson, and Hamwi formulas plus healthy BMI range. Enter height and sex for instant results.
- [Macronutrient Split Calculator](https://captaincalc.com/calculator/macro-calculator/): Calculate your daily macros in seconds. Enter calories, choose keto, balanced, high-protein, or a custom split — get exact protein, carb, and fat gra…
- [Daily Water Intake Calculator](https://captaincalc.com/calculator/water-intake-calculator/): Calculate your daily water intake in liters and glasses based on body weight, activity level, and climate. Get a personalized hydration recommendatio…
- [Target Heart Rate Zone Calculator](https://captaincalc.com/calculator/target-heart-rate-calculator/): Calculate your 5 heart rate training zones using the Karvonen formula and % of max HR. Enter age and resting HR to get fat burn, cardio, and peak zon…
- [One-Rep Max (1RM) Calculator](https://captaincalc.com/calculator/one-rep-max-calculator/): Calculate your One-Rep Max (1RM) using Epley, Brzycki & Lombardi formulas. Get a full training percentage table to plan your strength program.
- [Waist-to-Hip Ratio Calculator](https://captaincalc.com/calculator/waist-to-hip-ratio-calculator/): Calculate your waist-to-hip ratio instantly and discover your cardiovascular risk category based on WHO thresholds for men and women.
- [Pregnancy Due Date Calculator](https://captaincalc.com/calculator/pregnancy-due-date-calculator/): Calculate your pregnancy due date and current week from your last menstrual period using Naegele's rule. Get trimester breakdown and days remaining i…
- [Calories Burned by Activity Calculator](https://captaincalc.com/calculator/calories-burned-calculator/): Calculate calories burned for 50+ activities using MET values, body weight and duration. Get accurate estimates for running, cycling, swimming, yoga …

## Articles

- [Business Number Pricing Explained: g100.us vs the Rest](https://captaincalc.com/g100us-pricing-explained/): Business number pricing explained: g100.us offers flat $4/week numbers with calls, SMS & WhatsApp included—no contracts, no per-seat fees.
- [Can One Number Handle Calls, Texts & WhatsApp? Yes — g100.us](https://captaincalc.com/can-one-number-calls-texts-whatsapp-g100us/): Can one number handle calls, texts, and WhatsApp? Yes. g100.us gives you one business number for all three, in 100+ countries, live in seconds.
- [The Complete Pre-Workout Checklist for Safe Training](https://captaincalc.com/pre-workout-safety-checklist/): Use this pre-workout checklist to verify heart-rate zones, hydration, warm-up structure and load selection before every training session for safer, s…
- [Mifflin-St Jeor vs Harris-Benedict: Which BMR Formula Wins](https://captaincalc.com/bmr-formula-comparison/): Compare Mifflin-St Jeor vs Harris-Benedict BMR formulas with real numbers, error margins, and research findings to determine which equation to trust …
- [Why Fitness Trackers Keep Overstating Your Calorie Burn](https://captaincalc.com/fitness-trackers-calorie-accuracy/): Fitness trackers overstate calorie burn by up to 93%, per Stanford research. Learn why, which workouts are worst-affected, and how to diet smarter de…
- [What Is BMR? Calories Explained Like You're Five](https://captaincalc.com/what-is-bmr-explained-simply/): What is BMR? Learn what basal metabolic rate means in plain English — where your calories go, what affects your BMR, and how to use it for weight goa…
- [What 50 Studies Say About Protein Intake for Muscle](https://captaincalc.com/protein-intake-research-muscle/): What 50+ studies reveal about protein intake for muscle: optimal g/kg targets, timing research, per-meal thresholds, and where diminishing returns be…
- [No, You Don't Need 8 Glasses of Water a Day](https://captaincalc.com/eight-glasses-water-myth/): Debunking the 8 glasses of water myth: where it came from, what research actually says, and how to calculate your real hydration needs by body weight…
- [Your Body Fat Percentage Questions, Answered](https://captaincalc.com/body-fat-percentage-questions/): Body fat percentage questions answered: healthy ranges by age and sex, tape measure vs BIA scale vs DEXA accuracy, and how to track at home without o…
- [10 Body Metrics That Matter More Than the Scale](https://captaincalc.com/body-metrics-beyond-the-scale/): Discover 10 body metrics that reveal more than bodyweight alone — body fat %, waist-to-hip ratio, resting heart rate, HRV, and more. Track what actua…
- [Calculate Your Macros in 5 Simple Steps](https://captaincalc.com/how-to-calculate-your-macros/): Why Counting Macros Actually Works (Unlike Most Diet Advice) Plenty of people eat "clean" for years without ever knowing what they're actually puttin…
- [The Science of TDEE: How Many Calories You Really Burn](https://captaincalc.com/science-of-tdee-calories/): Learn the science of TDEE: how BMR, NEAT, thermic effect of food, and exercise thermogenesis each contribute to your daily calorie burn, with researc…
- [How to Read Your BMI Without Freaking Out](https://captaincalc.com/understanding-your-bmi-results/): Learn what BMI really measures, why it misclassifies muscular people, and how to interpret your number alongside waist circumference, body fat, and b…
- [Percentage Calculator — How to Calculate Percentages (With Examples)](https://captaincalc.com/percentage-calculator-how-to-calculate-examples/): Complete GST guide explaining tax rates, registration, filing, input tax credit, and compliance requirements for businesses.
- [How to Calculate Tips — Tipping Etiquette Guide for Every Situation](https://captaincalc.com/how-to-calculate-tips-tipping-guide/): Comprehensive guide to Section 80C tax-saving investments. Compare ELSS, PPF, NPS, and other options for maximum tax benefits.
- [401(k) Retirement Calculator — How Much Do You Need to Retire?](https://captaincalc.com/401k-retirement-calculator-how-much-need/): Essential income tax planning guide for salaried individuals. Learn about tax slabs, deductions, exemptions, and saving strategies.
- [BMI Chart for Men and Women — What Your BMI Really Means](https://captaincalc.com/bmi-chart-men-women-what-it-means/): SIP vs Lump Sum investing comparison. Understand rupee cost averaging, returns comparison, and which strategy suits your goals.
- [How to Calculate Mortgage Payments — Complete Guide with Formula](https://captaincalc.com/how-to-calculate-mortgage-payments-guide/): Complete guide to understanding EMI calculations. Learn the formula, factors affecting EMI, and tips to reduce your monthly payments.

## About & Policies

- [About Us](https://captaincalc.com/about-us/)
- [Contact Us](https://captaincalc.com/contact-us/)
- [Privacy Policy](https://captaincalc.com/privacy-policy/)
- [Terms of Service](https://captaincalc.com/terms-of-service/)
- [Disclaimer](https://captaincalc.com/disclaimer/)
- [Blog](https://captaincalc.com/blog/)

## Notes

- Full URL list: https://captaincalc.com/sitemap.xml
- Content is original and maintained by Captain Calc. Attribution is appreciated when cited.