CalcMega Blog
Every calculator, explained in plain English — the formula behind it, a worked example with real numbers, honest tips, and the questions people actually ask. New guides are added daily as tools go live.
💰 Financial
What PITI + PMI really means, the one formula every fixed-rate mortgage uses, and a $350,000 worked example — including how a 15-year term saves $198,086.46 in interest.
28 Oct 2026 · 6 min read
The 30% rule worked on a $72,000 salary — why debts can lower the ceiling to $1,760, how landlords' 3× test really works, and how to split rent fairly when incomes differ.
28 Oct 2026
One equation, four directions: payment, amount, term or rate. Plus the table that exposes payment shopping — $10,000 over 3 years at 5% vs 20%, where the interest quadruples while the payment barely moves.
28 Oct 2026
Sellers quote payments because payments hide rates. Three deals decoded — 6.28%, a suspicious 2.67%, and a mortgage at 6.47% — plus the two-minute showroom routine.
28 Oct 2026
N, I/Y, PV, PMT, FV — the five numbers behind every loan and pension. Three classic problems solved, the sign convention explained, and a $99-a-month sofa exposed at 27.8% APR.
28 Oct 2026
$6,500 at 24.99% APR costs $12,401.74 in interest on minimum payments — or $2,957.47 at $250 a month. The full table, the freeze-the-minimum trick, avalanche vs snowball.
28 Oct 2026
A $30,000 loan at 7.5% really costs $36,068. See what tax and fees do to the amount financed, why 72-month terms trap careful people, and the 20/4/10 sanity check.
28 Oct 2026
A lower rate isn't automatically a saving. This guide works a real break-even — 48 months on a $320,000 refinance — and shows when points, appraisals and clock-resets change the answer.
28 Oct 2026
$250 a month extra on a $300,000 mortgage saves $106,356.67 and ends it nearly 8 years early. Or see what one $10,000 lump sum does in month one.
28 Oct 2026
The 28/36 rule worked honestly on a $95,000 salary — and why the same family can afford $62,000 more house in one state than another, purely because of property tax.
28 Oct 2026
CalcMega is rolling out in daily batches — a few tools per category each day, and every tool launches together with its full guide on this page. Tomorrow's batch: Debt Payoff, Debt Ratio, Annuity, Annuity Payout and Bond calculators get their guides and go live.
Want a specific calculator covered sooner? It is probably already in the queue — check back tomorrow.