Sources & Methodology
This calculator uses the standard compound interest formula A = P(1 + r/n)^(nt) as defined by the FDIC and financial mathematics standards. Interest rate benchmarks sourced from FDIC.gov national deposit rate averages and the Federal Reserve H.15 release. Tax treatment based on IRS Publication 550.
How Certificate of Deposit Interest Works
A Certificate of Deposit (CD) is a savings product offered by banks and credit unions that pays a fixed interest rate over a set term. Unlike a regular savings account, you agree to leave the money deposited for the full term in exchange for a higher interest rate.
The CD Interest Formula
CD Rates: What to Expect in 2026
After a period of elevated rates, top CD rates in 2026 range from 4.0% to 5.5% APY for 1-year terms at online banks and credit unions. Traditional brick-and-mortar banks typically offer lower rates (0.5–2.5% APY). Shopping around and comparing APY — not APR — is essential to maximizing your earnings.
| CD Term | Typical Rate Range (2026) | Best For |
|---|
| 3 Months | 3.5–4.5% APY | Short-term cash parking |
| 6 Months | 4.0–5.0% APY | Near-term goals, emergency fund |
| 12 Months | 4.2–5.3% APY | Best value, most competitive |
| 18 Months | 4.0–5.0% APY | Mid-term savings goals |
| 24 Months | 3.8–4.8% APY | Rate lock, 2-year goals |
| 36–60 Months | 3.5–4.5% APY | Long-term lock-in |
CD Laddering Strategy
A CD ladder splits your deposit across multiple CDs with different maturity dates (e.g., 3, 6, 12, 18, and 24 months). As each CD matures, you reinvest in a new long-term CD, maintaining access to a portion of your funds every few months while still earning high rates. This balances liquidity with yield.
💡 Pro Tip: Online banks and credit unions consistently offer 1–3% higher APY than traditional banks for the same CD terms. Always compare APY (not just the stated rate) before committing. Sites like Bankrate and NerdWallet aggregate current CD offers for easy comparison.
Frequently Asked Questions
How is CD interest calculated? +
CD interest uses compound interest: A = P(1 + r/n)^(nt). P is your principal, r is the annual rate as a decimal, n is the number of times interest compounds per year (365 for daily, 12 for monthly), and t is the term in years. Most banks compound interest daily or monthly, which results in slightly more earnings than less frequent compounding. The difference between daily and monthly compounding is small — about $5 extra on a $10,000 CD at 5% for 12 months.
What is the difference between APR and APY on a CD? +
APR is the stated nominal rate. APY (Annual Percentage Yield) reflects the actual return after compounding. For a CD at 5% APR compounded daily, the APY is 5.127%. The more frequently interest compounds, the higher the APY vs APR. Federal law (Truth in Savings Act) requires banks to disclose APY, so when comparing CDs, always use APY as your comparison metric.
What happens when a CD matures? +
When your CD matures, you have a grace period (typically 7–10 calendar days) to withdraw funds or redirect them. If you take no action, most banks auto-renew the CD at the current rate for the same term. Always review the renewal rate — it may be much lower than your original rate. Set a calendar reminder before your CD matures to shop for the best rate.
Are CDs FDIC insured? +
Yes. CDs at FDIC-insured banks are covered up to $250,000 per depositor, per institution, per ownership category. CDs at NCUA-insured credit unions have the same protection. This makes CDs one of the safest places to hold cash — the only risk is opportunity cost (inflation or better rates elsewhere) and early withdrawal penalties.
Is CD interest taxable? +
Yes. CD interest is taxed as ordinary income at your marginal federal tax rate. It's reported on a 1099-INT issued by your bank. You owe tax on interest in the year it's credited to your account — even if you don't withdraw it. One strategy: hold CDs in a traditional or Roth IRA to defer or eliminate the tax. IRA CDs work the same way as regular CDs but with tax advantages.