Calcnio blog · 27 published
The blog that shows the math.
Clear, worked-out explanations of how borrowing, interest, saving and everyday numbers really work, each with real figures and a free calculator to try your own.
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Saving & investing
Simple vs Compound Interest: Examples That Show the Difference
Simple vs compound interest explained with worked examples: see how $8,000 grows at 5% over 30 years, where each type shows up, and when it works against you. -
Saving & investing
The Rule of 72: How Fast Will Your Money Double?
Learn the Rule of 72 shortcut for estimating how long money takes to double, how accurate it is at different rates, and how to use it for inflation, fees and debt. -
Mortgages
Rent vs Buy: How to Compare the Real Costs Side by Side
Compare the real costs of rent vs buy, side by side: interest, taxes, upkeep, selling costs and lost growth on your down payment, plus the break-even year. -
Debt
How to Pay Off Credit Card Debt Fast: A Step-by-Step Plan
A step-by-step plan to pay off credit card debt fast: stop new charges, set a fixed payment, cut your rate with a transfer or loan, and see the real numbers. -
Saving & investing
What Inflation Really Does to Your Savings (With Examples)
An inflation savings guide with real numbers: see what 2% to 6% inflation does to $20,000 in cash, how to work out your real return and how to protect it. -
Mortgages
What Is PMI and How Do You Get Rid of It?
Learn how to get rid of PMI: when you can request cancellation at 80%, when it ends automatically at 78%, and how extra payments can remove it years sooner. -
Loans
How to Calculate a Loan Payment (By Hand and in Excel)
Here is how to calculate loan payment amounts by hand or with Excel's PMT function, using a worked $15,000 example and tables for different rates and terms. -
Saving & investing
How Much Will $500 a Month Grow in 10, 20 and 30 Years?
How much will $500 a month grow? See exact balances after 10, 20 and 30 years at 4%, 6% and 8%, plus the cost of waiting and what inflation does to the total. -
Mortgages
How Much House Can I Afford? The 28/36 Rule With Examples
How much house can I afford? Use the 28/36 rule and a worked example to turn your income, debts and down payment into a realistic maximum home price. -
Loans
How Loan Interest Is Calculated: Amortization Explained With Real Numbers
How lenders calculate interest on amortizing loans, why early payments are mostly interest, and how flat-rate quotes can nearly double your cost. -
Debt
How Credit Card Interest Is Calculated (Daily Rate Explained)
How is credit card interest calculated? See the daily rate and average daily balance method step by step, plus how grace periods and payment timing change it. -
Debt
Debt Snowball vs Debt Avalanche: Which Pays Off Debt Faster?
Debt snowball vs avalanche, tested month by month on four debts with one budget: total interest, months to debt-free, and how to pick the method you'll keep.
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