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Calculator Guides & Blog

Expert guides on EMI, SIP, GST, BMI, TDEE, percentages, and more. India-first finance, health, and math tutorials reviewed by Mayra.

37 Guides
3 Categories
Free Always
💰 Finance 20
🏦EMI Guide: Flat Rate vs Reducing Balance & TypesHow Indian banks calculate EMI: flat rate vs reducing balance, what affects your EMI, and…🧮How to Calculate EMI Manually – Formula, Steps & ExamplesCalculate EMI manually using the reducing balance formula. Step-by-step worked examples…📑EMI vs Loan vs AmortizationUnderstand the difference between EMI, loan principal, and amortization. Includes worked…🎯How to Pay Off Debt FastPay off debt faster with the avalanche or snowball method. India credit card vs personal…🧾Understanding GST in IndiaA complete guide to GST in India: rate slabs, ITC rules, filing calendar, and how to…How to Calculate GST – Add or Remove TaxLearn how to add or remove GST from any price with clear formulas and examples. Covers…🔁GST Inclusive vs Exclusive: Formula & ExamplesLearn the difference between GST-inclusive and GST-exclusive prices with formulas, worked…📈How Compound Interest WorksWhy compound interest grows wealth faster. Monthly vs daily compounding table, Rule of…⚖️Simple vs Compound Interest – Formulas & ExamplesUnderstand simple and compound interest with clear formulas, side-by-side comparisons and…🏛️FD vs RD vs SIP: Where Should Your Money Go?FD vs RD vs SIP compared for India: returns, risk, taxation, liquidity, and goal-based…💹SIP vs Lump Sum – Which is Better?Compare SIP vs lump sum investment strategies with real examples. Find out when SIP wins…📊How to Calculate Investment Returns – ROI & CAGRLearn how to calculate ROI, CAGR and inflation-adjusted returns. Includes worked examples…🛡️PPF vs EPF vs NPS: Which Retirement Option Wins?PPF vs EPF vs NPS compared: returns, tax benefits, lock-in, liquidity, and who should…🌅Retirement Planning BasicsEstimate your retirement corpus in 5 steps. Covers EPF, NPS, safe withdrawal rate, and…🗂️Financial Planning with Online CalculatorsThe right calculator for every money decision: EMI, SIP, mortgage, compound interest…📋The 50/30/20 Budget Rule ExplainedLearn how the 50/30/20 budget rule works: 50% needs, 30% wants, 20% savings. Includes…💎How to Calculate Your Net WorthLearn exactly how to calculate your net worth step by step. Understand what counts as an…💻How to Set Your Freelance Rate in 2026Calculate your minimum viable freelance rate using expenses, taxes, and billable hours…🏠Mortgage vs Rent: Numbers to CompareCompare renting vs buying a home beyond monthly payments. Learn key inputs, examples…🔄When Is Mortgage Refinancing Worth It? Break-Even GuideCalculate if refinancing your home loan saves money. Use the break-even formula, India…
❤️ Health & Fitness 13
🔥BMR vs TDEE: Difference, Formula & UsesBMR is calories at rest. TDEE adds your activity level. Learn the difference, when to use…How to Calculate TDEE for Fat Loss & Muscle GainCalculate your Total Daily Energy Expenditure using BMR and activity multipliers…🍎Daily Calorie Needs ExplainedFind your maintenance calories by age, weight, and activity. India food reference…🍽️How Many Calories Should I Eat Per Day?Find your personalised daily calorie target based on age, gender, weight and activity…⚖️Understanding BMI and Its LimitationsWhy BMI is not enough: Asian cutoffs, athlete inaccuracy, visceral fat risk, and…📏How to Calculate Body Fat PercentageCalculate body fat percentage using the Navy method and BMI formula. Includes healthy…💓How to Calculate Heart Rate ZonesCalculate your five heart rate training zones using max HR and the Karvonen method. Find…🩺What Is a Good Blood Pressure? Ranges & Charts 2026Normal blood pressure is below 120/80 mmHg. See the full BP chart by age, understand…📈How to Track Fitness MetricsUse BMI, BMR, TDEE, body fat, protein, and heart rate tools together for a full fitness…🏃Running for Weight Loss: Distance, Pace & FrequencyHow much running is needed to lose weight? Covers calorie burn by pace and weight, weekly…🚶How to Lose Weight by WalkingWalking for weight loss: steps, distance, pace and calorie burn. Includes Indian walking…🔥Running vs Walking CaloriesDoes running burn more calories than walking? Learn the science, compare burn rates per…👟How Long Does It Take to Walk 10,000 Steps?Find out how long 10,000 steps takes, how many calories you burn, and the distance…
📐 Math & Everyday 4
%Percentage Calculation Made SimpleMaster percentage formulas: percentage of a number, percentage change, reverse…📉How to Calculate Percentage Increase or DecreaseMaster percentage increase and decrease formulas with 8 real-world examples covering…🎂Age Calculation ExplainedHow age calculators work: exact age in years, months, days; leap year handling; calendar…🎓How to Use a Grade Curve CalculatorLearn how grade curving works, when teachers apply it, and how to calculate curved scores…

About these guides

Every guide on the iCalcApp blog is written and reviewed by Mayra. Guides are linked directly to the relevant calculator so you can apply the formula immediately after reading.

Finance guides use India FY 2025-26 tax slabs, GST rates, and RBI guidelines. Health guides follow WHO and ICMR 2024 standards. All content is updated when regulations change.

Start here by goal

I want to borrow smart: begin with how EMI really works — it explains why two loans with the same rate can cost differently, then the EMI vs loan vs amortization piece tells you which calculator fits your exact question. I want to grow money: compound interest first (the maths everything else builds on), then FD vs RD vs SIP for where to put monthly savings. I want to fix my health numbers: BMR vs TDEE answers the question most people get wrong — which number to eat by — and daily calorie needs turns it into a target.

Guides by category

Finance (20 guides): borrowing (EMI, debt payoff, mortgage vs rent), investing (SIP, compound interest, ROI/CAGR), India tax (GST series, income-tax adjacent HRA/gratuity coverage), and retirement (corpus planning, PPF/EPF/NPS). Health (13 guides): energy and weight (calories, TDEE, walking/running), body metrics (BMI limitations, body fat), and training (heart-rate zones, fitness tracking). Math & everyday (4 guides): percentages, age calculation, and grade curves. Every guide links its companion calculator so you can apply each concept as you read.

How to use these guides

Every guide on this page pairs with a working calculator — the guide explains the formula, the rules, and the decision logic; the calculator does the arithmetic. The India finance cluster (EMI, GST, income tax, PPF/EPF/NPS, HRA, gratuity) reflects FY 2025-26 rates and Budget changes; health guides follow WHO and ICMR reference standards; and every comparison piece (FD vs RD vs SIP, PPF vs EPF vs NPS, BMR vs TDEE) ends with a worked decision framework rather than a vague “it depends.”

Which guides should you start with?

Borrowing: start with how Indian banks calculate EMI, then avalanche vs snowball payoff. Investing: compound interestSIP vs lump sumFD vs RD vs SIP. Retirement: the 5-step corpus planPPF vs EPF vs NPS. Tax: GST in India and GST calculation formulas. Health: BMR vs TDEEdaily calorie targets.

How these guides are produced and reviewed

Every guide follows the same production standard: the formula or rule is traced to its primary source first (Income Tax Act sections, CBIC notifications, EPFO circulars, WHO/ICMR reference ranges, or the original peer-reviewed equation), worked examples are computed by hand and cross-checked against the matching calculator, and the draft is reviewed by Mayra (MBA Finance) before publication. Finance guides are re-verified after every Union Budget; health guides when WHO or ICMR guidance changes. Each page shows its last-reviewed date, and corrections ship within 48 hours under our editorial policy.

What makes these different from generic finance blogs?

Three things. First, every claim is calculable — if a guide says a ₹20 lakh income owes ₹1,92,400 under the new regime, the income tax calculator will reproduce that number with the same inputs. Second, India-first specificity: GST slabs, FY 2025-26 tax rules, EPFO rates, and lakh/crore formatting are native, not an afterthought. Third, comparison guides end in decision frameworks with explicit break-even numbers — the PPF vs EPF vs NPS guide tells you which wins at which deduction level, not just "evaluate your goals."

Frequently asked questions

What topics does the iCalcApp blog cover?

The blog covers personal finance (EMI, SIP, GST, tax, budgeting, debt payoff), health and fitness (BMI, calories, TDEE, body fat, blood pressure), and mathematics (percentage, compound interest, statistics).

Are the blog guides updated regularly?

Yes. Finance guides are updated when Indian regulations change (GST rates, income tax slabs, EPF rules). Health guides are updated when WHO or ICMR publish revised guidelines.

How do the blog guides relate to the calculators?

Each guide explains the formula and concept behind a specific calculator. After reading, you can use the linked calculator to apply the formula to your own numbers instantly.

Who writes the iCalcApp blog?

All blog content is written by Mayra, financial analyst, and reviewed for accuracy before publication.

Can I use the blog content for research?

Yes — all content is freely available. For academic or professional use, please cite iCalcApp and the specific calculator URL. Sources and methodology are documented at the methodology page.