Comprehensive Guide
Learn more in our Personal Finance Guide.
How it works
A CD early-withdrawal penalty is almost universally quoted in months of interest — commonly three to six months on short terms and twelve or more on long ones — charged as simple interest on principal regardless of how long the CD has run. The calculator applies that standard structure: monthly interest equals deposit times APY divided by twelve, the penalty is that figure times the penalty months, and net proceeds are principal plus interest earned minus the penalty. On the defaults — $25,000 at 4.3%, twenty-four-month term, four-month penalty, broken at month ten — earned interest totals about $896 while the penalty removes $358, keeping roughly $538 of the earnings and all of the principal. The strategic column answers the real question: does breaking beat holding? Proceeds reinvested at an alternative rate compound over the remaining term against what the untouched CD would reach at maturity; here, moving to a 4% savings account trails the original CD by several hundred dollars, quantifying exactly when patience pays. Two rules of thumb emerge from the math. Never break for a rate improvement smaller than the penalty drag — the bar is usually half a percentage point or more — and never break for emergencies that a properly sized emergency fund should have absorbed, because penalties punish precisely the liquidity CDs were never meant to provide.Formula
Penalty = deposit × (APY ÷ 12) × penalty months | Net = principal + interest earned − penalty
Tips
- Read the truth-in-savings disclosure — penalty months are stated there before you buy.
- Never break for rate gains smaller than the penalty's annualized drag (often 0.5%+).
- Ask about partial withdrawals — some banks penalize only the amount withdrawn.
- At maturity use the grace window (usually 7–10 days) to exit penalty-free.
- No-penalty CDs exist for money that might need earlier access — pay slightly less yield for optionality.