Finance guides
Understand interest, loans, discounts, profit and investment returns with plain-English guides.
15 guides · each with a free step-by-step calculator
How to Calculate Simple Interest (Formula)
Ever wondered why a savings account statement shows the exact same interest amount every single year? That's simple interest at work, and it's one of the easiest formulas in all of finance. By the end of this guide, you'll be able to work it out on paper in seconds.
How Compound Interest Works (Formula)
Why do bankers call compound interest one of the most powerful forces in finance? Because interest that earns its own interest snowballs faster than most people expect. This guide breaks down exactly how, with a formula you can use on any account.
How to Calculate a Tip (Step-by-Step)
Splitting a bill with friends and someone asks, "how much is 18% of $80?" Don't freeze — tipping is just a percentage calculation, and once you know the trick, you can do it in your head before the check even arrives.
How to Calculate Loan EMI (Formula Guide)
Two people take out the exact same loan amount, but one pays it off in 15 years and the other in 30. Why is the monthly payment so different, and why does the first payment barely touch the principal? The EMI formula explains both.
How to Calculate a Discount Price
A store advertises "25% off" — but is the sticker price actually right? A discount is just a percentage calculation, and once you know the formula, you can check any sale price yourself in seconds.
How to Calculate Profit or Loss Percentage
You bought something, fixed it up, and sold it for more. But was it actually a good deal? Turning the raw dollar profit into a percentage lets you compare it fairly against any other sale, no matter the price.
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How to Calculate Sales Tax or GST
You see a laptop priced at $850, but the checkout total is higher. That gap is sales tax, GST, or VAT — a percentage added on top of the price. Once you know the formula, you can estimate your final total before you even reach the register.
How to Calculate ROI (Return on Investment)
A stock that gained $1,500 and a small business that gained $1,500 sound identical — until you check how much each one cost to start. ROI turns any gain into a percentage, so you can finally compare them on equal footing.
What Is CAGR? Formula and Calculation
An investment goes up 50% one year and down 50% the next. Did it break even? Not even close — and CAGR is the formula that reveals the truth behind swings like that, boiling years of ups and downs into a single honest number.
How to Find the Break-Even Point
How many cups of coffee does a new café have to sell before it stops losing money? Every business has an answer, and it's called the break-even point — the exact moment revenue catches up to costs.
How to Calculate Profit Margin (Formula)
Two shops both sell a $1,000 item for a $400 profit. But if you ask "what percentage is profit," the answer depends entirely on whether you measure it against the sale price or the cost — and those two numbers aren't the same.
Straight Line Depreciation Explained Simply
A delivery van costs $30,000 brand new but won't be worth nearly that much in ten years. Straight line depreciation is the simplest way to track exactly how much value it loses, spread evenly across each year it's used.
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How to Calculate Future Value of Money
If you invest $3,000 today, what will it actually be worth in 8 years? Future value answers exactly that question, turning today's money and a growth rate into a single projected number.
How to Calculate Present Value of Money
Someone offers you $2,000 in 5 years instead of cash today. Is that a good deal? Present value converts any future payout into today's equivalent, so you can compare it fairly against money in hand right now.
How to Convert Salary to Hourly Rate
A $62,400 salary and a $30-an-hour job offer sound completely different — until you realize they might actually be worth the exact same thing. Converting salary to hourly makes any two pay structures easy to compare.
