CD Calculator Estimate maturity values, build ladders, model penalties, and compare rates — with 2025 benchmarks and liqu...
CD Calculator
Estimate maturity values, build ladders, model penalties, and compare rates — with 2025 benchmarks and liquidity insights.
Compound Interest Formula**:
$$FV = P \left(1 + \frac{r}{n}\right)^{nt}$$
Where: • $P$ = principal • $r$ = APY (decimal) • $n$ = compounding periods/year • $t$ = term in years
Example** ($10K @ 5.00% APY, 18 mos, daily compounding): $$FV = 10{,}000 \times \left(1 + \frac{0.05}{365}\right)^{365 \times 1.5} = \mathbf{\$10{,}767.08}$$ Interest = **$767.08**
✅ Pro Tip**: APY already includes compounding — use it directly (no need to convert from APR).
⚠️ Avoid these pitfalls:
- Teaser APYs** — “5.25% for 3 months” → 0.50% after
- Brokered CD hidden fees** — 0.25% load + $50 trade fee (Fidelity, Schwab)
- IRA CD RMD traps** — 5-yr IRA CD maturing after 73 → penalty if not liquid
- Auto-renewal traps** — 0.10% renewal rate if you miss the 10-day window
✅ Smart CD Strategies**:
- Build a **CD ladder** for yield + liquidity
- Use **no-penalty CDs** (e.g., Ally, Marcus) for emergency funds
- Lock **jumbo CDs** (>25% of FDIC limit) across multiple banks
| Term | National Avg APY | $10K Maturity |
|---|---|---|
| 3-Month | 4.25% | $10,106 |
| 12-Month | 4.75% | $10,485 |
| 18-Month | 5.00% | $10,767 |
| 3-Year | 4.60% | $11,454 |
| 5-Year | 4.30% | $12,380 |
📉 Early Withdrawal Math** ($10K @ 5.00%, 18-mo, withdraw at 6 mos, 90-day penalty):
- Accrued interest: $247
- Penalty: 90/365 × 5% × $10,000 = $123
- Net withdrawal: $10,000 + $247 − $123 = **$10,124**
- If held to maturity: **$10,767** → **$643 lost**
➡️ Standard CD
“$10K @ 5.00% for 18 mos — what’s my maturity value?” ($10,767)
➡️ CD Ladder
Model a 5-rung ladder — see average yield and maturity schedule.
➡️ Early Withdrawal
“I need $10K in 6 mos — what penalty will I pay?” ($123 + $520 opportunity cost)
➡️ Rate Comparison
Compare 3-mo vs. 18-mo — see when longer terms stop paying more.
Note: Uses exact compound formulas. APY assumed fixed. Penalties based on lost interest (most common structure).