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Knowledge Base
Tips, guides, and insights for smarter decisions
CAGR with Contributions: Avoid Counting Your Deposits as Investment Return
Test whether CAGR is valid when an account has deposits or withdrawals, reproduce a misleading example, and choose a cash-flow-aware return instead.
Will a 2 TB Drive Hold the Backup? Size Capacity with TB, TiB, Growth, and Retention
Convert TB and TiB consistently, add retained data growth and an explicit planning margin, and test whether a nominal backup capacity is actually large enough.
Choose a Cloud Subnet CIDR by Usable IPs, Not Address Count
Size an IPv4 cloud subnet from real workload demand, provider-reserved addresses, and growth headroom, with a reproducible /26 versus /25 example.
Estimate the Long-Term Cost of an Investment Fee with Compound Interest
Compare two hypothetical annual fees on the same portfolio assumptions, reproduce the 20-year balances, and identify costs the simple model leaves out.
Estimate TDEE After Your Activity Changes—and Treat It as a Starting Range
Reproduce a Mifflin–St Jeor estimate, compare Calquio's activity bands, and use observed trends without mistaking predicted calories for a measurement.
APY vs. APR: Compare Savings Rates on the Same Basis
Convert a nominal annual rate to APY, reproduce a 5% monthly-compounding example, and compare deposit offers without mixing unlike rate disclosures.
Compare a Pay Raise with Inflation Without Mixing Nominal and Real Salary
Reproduce a salary-versus-inflation example, calculate the purchasing-power gap, and prepare a compensation discussion without overstating what CPI proves.
15-Year vs. 30-Year Mortgage: Compare Payment, Interest, and Cash-Flow Risk
Reproduce a same-rate mortgage comparison, quantify the monthly-payment and total-interest trade-off, and stress-test the term against household cash flow.
Calculate an Estimated Due Date—and Plan Around a Window, Not One Day
Reproduce a last-menstrual-period due-date estimate, test cycle-length assumptions, and separate calendar planning from clinical pregnancy dating.