Guides — page 2

What each car loan length really costs, why 72 and 84-month loans leave you underwater, and how to pick a term that fits.

Avalanche saves the most interest; snowball keeps you going. A real comparison, when they're identical, and what matters more than either.

Credit card interest is charged daily on your average balance. How it works, how you lose the grace period, and why minimum payments barely help.

The EMI formula with a worked example, where each payment goes, the flat-rate trick that doubles your interest, and how prepayments save money.

Three to six months of essential costs — here's how to work out yours, when you need more, where to keep it and how to build it without stalling.

Where the 4% rule came from, how to use it to set a retirement target, why experts now argue for 3.7% or 4.7%, and what it doesn't account for.

Why a savings balance that never falls can still lose value, how to work out your real return, the rule of 70, and ways to protect your money.

Simple interest is paid on the original amount; compound interest grows on itself. Formulas, a 30-year comparison, APR vs APY, and where each is used.

The ROI formula with examples, why you must annualize to compare investments fairly, ROI for marketing, and what ROI leaves out.

Markup is profit over cost; margin is profit over price. The formulas, a conversion table, how discounts eat margin, and which one to use.

Add VAT by multiplying by 1.2; remove it by dividing — not by taking 20% off. UK rates, zero-rated vs exempt, and GST/HST in other countries.

Save any YouTube thumbnail in the largest size available, on a computer or phone. Every size YouTube makes, how the URLs work, and fixes for common problems.