# The Math Says: Calculator Hub for Big Financial Decisions

Canonical: https://themathsays.com/

> Twelve calculators for big loan, refinance, insurance, and payoff decisions. Each gives a clear verdict (✅/⚠️/❌), math shown. Published formulas, anti-marketing.

## Mortgage & refinance

[06 Should I refinance to remove PMI? Most popular PMI runs $50-$400/month. Break-even, FHA-vs-conventional logic, and the free-cancellation path most servicers won't volunteer.](https://themathsays.com/calculators/refinance-to-remove-pmi-calculator/)

[05 30-to-15 year refinance Refinancing to a 15-year mortgage can save $150-$250k in interest. The catch: the higher payment is real. Affordability check + verdict.](https://themathsays.com/calculators/30-to-15-year-refinance-calculator/)

[09 FHA to conventional refinance Escape lifetime FHA MIP. Break-even + the 20% equity threshold + the cases where it doesn't pay yet.](https://themathsays.com/calculators/fha-to-conventional-refinance-calculator/)

[02 ARM vs fixed mortgage Monthly savings during the fixed period, what happens if the ARM adjusts to its cap, verdict based on how long you plan to stay.](https://themathsays.com/calculators/arm-vs-fixed-mortgage-calculator/)

[12 Mortgage refi break-even When does the refinance pay off? Break-even, lifetime interest delta, verdict.](https://themathsays.com/calculators/mortgage-refinance-break-even-calculator/)

[04 Bi-weekly mortgage payments Real savings (years off the loan). Plus the simpler alternative that captures the same result with more flexibility, and why you should never pay for a bi-weekly program.](https://themathsays.com/calculators/biweekly-mortgage-payment-calculator/)

## Home equity

[07 HELOC vs cash-out refinance Right answer depends entirely on how long you'll carry the debt, and whether your current first-mortgage rate is below today's market.](https://themathsays.com/calculators/heloc-vs-cash-out-refinance-calculator/)

[08 Home equity loan vs cash-out The third option most lenders won't volunteer. Fixed rate, low closing costs, doesn't disturb your existing first mortgage.](https://themathsays.com/calculators/home-equity-loan-vs-cash-out-calculator/)

## Investing & payoff

[03 Pay off mortgage early vs invest After-tax comparison most calculators skip. The answer flips for households that don't itemize, which is most of them post-2017.](https://themathsays.com/calculators/pay-off-mortgage-vs-invest-calculator/)

## Insurance

[01 Insurance deductible optimizer Featured Should you raise your deductible to drop your premium? Break-even based on your actual claim frequency + savings cushion check.](https://themathsays.com/calculators/insurance-deductible-optimizer/)

## Auto

[10 Lease vs buy car (true total cost) 3-year lease vs 3-year purchase always favors the lease. The real comparison is over 8-12 years of leasing-forever vs buying-and-holding.](https://themathsays.com/calculators/lease-vs-buy-car-calculator/)

[11 Auto loan refinance Real savings + the underwater trap most refi calculators don't flag.](https://themathsays.com/calculators/auto-loan-refinance-calculator/)

## What makes these different

- **Verdicts, not bare numbers.** Bankrate's calc tells you "you'd save $213/month." Ours tells you "✅ break-even in 22 months, green light if you're staying 3+ years." The interpretation is the point.

- **Standard formulas.** Every one is the published version. PMT for amortizing loans, future-value for time comparisons, real after-tax math. No black-box tricks.

- **Anti-marketing.** When the math says "don't do this," our calculator says "don't do this." Lenders' calculators are biased toward "apply now." Ours have no idea our affiliates exist.

- **Built for the deciding moment.** Not "what is a mortgage." For people about to sign something.

If you found this useful, odds are the math said something inconvenient. We'd rather show you that than push you toward a click.