CD Calculator Examples: Different Terms and Rates

July 16, 2026

Three worked examples below, using the same APY-based formula the CD calculator runs, plus an early withdrawal penalty scenario. For term definitions, see the CD terms glossary.

Example 1 — 18-Month CD

$15,000 at 4.2% APY, 18-month term

Exponent = 18 months ÷ 12 = 1.5
Value at Maturity = $15,000 × (1.042)^1.5 = $15,954.85

That’s $954.85 in total interest over the 18-month term.

Example 2 — 2-Year CD

$40,000 at 4.35% APY, 2-year term

Value at Maturity = $40,000 × (1.0435)^2 = $43,555.69

That’s $3,555.69 in total interest — notice this is more than double Example 1’s dollar interest despite a smaller APY, simply because the term is longer and the principal is larger.

Example 3 — 9-Month CD

$8,000 at 4.75% APY, 9-month term

Exponent = 9 months ÷ 12 = 0.75
Value at Maturity = $8,000 × (1.0475)^0.75 = $8,283.34

Early Withdrawal Penalty Scenario (Based on Example 3)

Suppose the Example 3 CD needs to be broken at the 6-month mark, with a bank penalty of 3 months’ interest:

Value at 6 months = $8,000 × (1.0475)^0.5 = $8,187.80
Interest earned by 6 months = $187.80

3-month penalty = $8,000 × 4.75% × (3 ÷ 12) = $95.00
Net payout after penalty = $8,187.80 − $95.00 = $8,092.80

The penalty ($95.00) consumes about half of the $187.80 in interest actually earned by that point — a real cost, though it doesn’t dip into the original $8,000 principal in this case. On a CD broken even earlier, before enough interest has accrued to cover the penalty, the shortfall would come out of principal instead. See common CD calculator mistakes for more on planning around this risk.

Try Your Own Numbers

Enter your actual deposit amount, APY, and term into the CD calculator — and see CD laddering strategy if you’re deciding between one large CD and several staggered ones.