The math behind every calculator

How to calculate After-Repair Value and Maximum Allowable Offer using the 70% Rule — the core math behind every profitable fix-and-flip deal.

Find the minimum occupancy rate needed to cover operating costs and debt service — the number lenders and investors watch most closely.

Why CMBS and institutional lenders look at debt yield (NOI ÷ loan) before LTV or DSCR, and how to calculate the metric that gets deals taken seriously.

How commercial real estate profits are split between LPs and GPs through multi-tier IRR hurdles, preferred returns, and promote structures.

Calculate the real cost of hard money — points, effective APR, and total interest — so a short-term bridge loan doesn't eat your flip profit.

The two ratios that determine how much a lender will actually give you — and how to identify which one is your real borrowing constraint.

How to calculate pro-rata share, base rent, and the NNN expense split that determines your true monthly cost in a commercial lease.

How a wrap-around mortgage works as a seller-financing tool — modeling the spread between the underlying loan and the new wrap for buyer and seller.

The difference between Actual Cash Value and Replacement Cost — and why depreciation can leave a big gap between your claim and your check.

How an SBA 7(a) acquisition is structured — bank loan, buyer equity injection, and seller note — and the math that makes a deal financeable.

How the SBA 504 program stacks bank, CDC, and borrower funds for owner-occupied real estate — and how to calculate your blended rate.

How an earn-out gets a deal done when buyer and seller disagree on price — modeling base price, performance targets, and contingent payouts.

How business interruption insurance payouts are calculated — lost profit, continuing expenses, extra expense, and the restoration period.

Why underinsuring a commercial property triggers a coinsurance penalty — and how to calculate your exposure before you ever file a claim.

How to calculate net monthly savings, payback period, and annual ROI on industrial equipment — the numbers that justify a capital purchase.

How inverse net-yield procurement eliminates scrap-rate shortfalls — calculating the gross order quantity you actually need to hit a target.

How content websites are valued using broker-grade revenue multiples — and the factors that move a site's multiple up or down.

Everything you need to know about mortgage math — from amortization schedules to PMI removal, and how to calculate your true cost of homeownership.

A plain-English calculator and guide for estimating reverse mortgage proceeds, future balance growth, and remaining home equity.

How loan payments are calculated, why early payments go mostly to interest, and strategies to pay off loans faster and save thousands.

How car loan payments are calculated, when to buy vs. lease, how trade-ins affect financing, and what dealers don't want you to know.

Why Einstein may have called compound interest the eighth wonder of the world — and how to use it to build wealth through the math of exponential growth.

How to calculate your retirement number, why the 4% rule works, how Social Security fits in, and what most retirement projections get wrong.

How to convert between hourly, weekly, monthly, and annual pay — and why your gross salary and your actual take-home are very different numbers.

How sales tax is applied and removed from prices, why rates vary so much by state, and the reverse calculation formula every shopper should know.

How foreign exchange rates are set, what moves them, why bank rates differ from mid-market rates, and how to get the best exchange rate when traveling or sending money.

What DSCR means, how lenders use it to approve investment property loans, how to calculate NOI correctly, and what to do when your DSCR falls short.

How BMI is calculated, what the ranges mean, why it's useful as a screening tool but not a diagnosis, and what alternatives exist for measuring health.

The science behind BMR and TDEE, how the Mifflin-St Jeor formula works, why calorie calculators are estimates, and how to use them to reach your goals.

How due dates are calculated using Naegele's Rule, what each trimester means for development, why only 5% of babies arrive on their due date, and key milestones to track.

The three core percentage calculations, how to find percentage change vs. percentage of a number, and real-world applications from discounts to inflation.

A complete guide to every function on a scientific calculator — sin, cos, tan, log, ln, factorial, hyperbolic functions, and how to use the 2nd function key.

How to precisely calculate age in years, months, days, weeks, and hours — and why leap years, calendar differences, and cultural conventions make it more complex than expected.

Standard tipping rates by service type, the history of gratuity in America, how to split bills in a group, and whether you should tip on the pre-tax or post-tax amount.

Everyday arithmetic, the memory keys (M+, M-, MR, MC), and when a basic calculator beats a scientific one for fast, clean math.

How GPA is calculated using quality points and credit hours, the difference between weighted and unweighted GPA, and what GPA thresholds matter for college, grad school, and employers.

How weighted grades are calculated, the formula for determining the score you need on a final exam, and how different grading scales affect your letter grade.

The chemistry behind soap making — how saponification values determine exact lye and water weights, and how superfat protects your skin.