Compare HYSA, CD, and Mortgage scenarios
side-by-side, instantly.
📖 Dig Deeper
See all posts →Amortization schedule (24 rows)
| Month | Payment | Principal | Interest | Balance |
|---|---|---|---|---|
| 1 | 0 | 0 | 0 | 10,537.5 |
| 2 | 0 | 0 | 0 | 11,077.02 |
| 3 | 0 | 0 | 0 | 11,618.55 |
| 4 | 0 | 0 | 0 | 12,162.12 |
| 5 | 0 | 0 | 0 | 12,707.73 |
| 6 | 0 | 0 | 0 | 13,255.39 |
| 7 | 0 | 0 | 0 | 13,805.09 |
| 8 | 0 | 0 | 0 | 14,356.86 |
| 9 | 0 | 0 | 0 | 14,910.7 |
| 10 | 0 | 0 | 0 | 15,466.62 |
| 11 | 0 | 0 | 0 | 16,024.62 |
| 12 | 0 | 0 | 0 | 16,584.71 |
| 13 | 0 | 0 | 0 | 17,146.9 |
| 14 | 0 | 0 | 0 | 17,711.2 |
| 15 | 0 | 0 | 0 | 18,277.62 |
| 16 | 0 | 0 | 0 | 18,846.16 |
| 17 | 0 | 0 | 0 | 19,416.83 |
| 18 | 0 | 0 | 0 | 19,989.65 |
| 19 | 0 | 0 | 0 | 20,564.61 |
| 20 | 0 | 0 | 0 | 21,141.72 |
| 21 | 0 | 0 | 0 | 21,721.01 |
| 22 | 0 | 0 | 0 | 22,302.46 |
| 23 | 0 | 0 | 0 | 22,886.09 |
| 24 | 0 | 0 | 0 | 23,471.92 |
HYSA, CD, and Mortgage on one page
Bankrate, NerdWallet, and lender calculators each give you one product at a time. This tool puts HYSA / CD / MMA savings next to Fixed and ARM mortgage on a single page, so you can compare after-tax APY against monthly P&I in seconds. All math runs in your browser. Nothing is sent to a server.
APY vs APR
APY (Annual Percentage Yield) already accounts for compounding.APR (Annual Percentage Rate) does not. For a savings account, you almost always see APY; for a mortgage, you see APR. Convert with APY = (1 + APR/n)n - 1 where n is compounding periods per year (daily=365, monthly=12).
After-tax APY (Federal + State marginal)
Interest income is taxed at your ordinary income rate, not capital gains. Combined marginal rate ≈ federal + state. A 5% APY HYSA at federal 24% + state 9.3% (CA) yields only 5% × (1 - 0.333) ≈ 3.34% effective. Treasuries are state-tax-free, often making them the better after-tax pick in high-tax states. The tax toggle in this tool models the simple combined rate.
CD early-withdrawal penalty
Most banks charge an EWP equal to 3, 6, or 12 months of interest. Standard formula: penalty = principal × APY × (penaltyMonths / 12). Toggle "Withdraw at month X" with the EWP months field to model whether breaking your CD for a higher rate elsewhere is worth it.
30Y Fixed vs 5/1 ARM mechanics
A 30-year Fixed mortgage has a constant APR for the entire term. Monthly P&I from M = P × r / (1 - (1+r)-n), where r = APR/12, n = 360.
A 5/1 ARM is fixed for 5 years, then adjusts annually. After the initial period, the APR resets to index + margin, capped by the lifetime cap (commonly ±5 percentage points). This tool re-amortizes the remaining balance over the remaining term using the (capped) reset APR, so you see exactly what your post-reset payment would be.
Refinance break-even math
Closing costs typically run 2–5% of the loan amount. The break-even month isbreak-even = closingCosts / (currentMonthly - newMonthly). Plan to stay in the home longer than the break-even month for the refi to pay off. The compare panel auto-shows refi break-even when both A and B are mortgages.
PMI rule of thumb
Private Mortgage Insurance applies when LTV (loan / home value) exceeds 80%. Annual PMI rates run roughly 0.3–1.5% of the loan amount, divided by 12 for monthly. This tool defaults to a 0.5% annual rate when LTV crosses 80%; you can override directly.
FAQ
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Does state-level tax-deductibility get modeled?
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