Sources & Methodology
Interest is calculated using the compound interest formula: A = P(1 + r/n)^(nt), where P = principal, r = APY/100, n = compounding periods per year, t = years. This matches NCUA standard calculation methods.
What Is a Share Certificate?
A share certificate is a savings product offered by credit unions — the equivalent of a bank CD (certificate of deposit). You deposit a fixed amount for a fixed term at a guaranteed APY. At maturity, you receive your principal plus all earned interest.
Share Certificate vs. Bank CD
Both products work identically. The only difference is terminology: credit unions call members "shareholders," so their CDs are called "share certificates." Credit unions are member-owned nonprofits, so they often offer higher APYs than banks on equivalent products.
The Compound Interest Formula
💡 Rate Shopping Tip: Credit union share certificate rates often exceed bank CD rates by 0.25–0.75%. On a $10,000 deposit over 2 years, that difference can add $50–$150 in extra earnings. Always compare APY, not just APR.
Frequently Asked Questions
What is a share certificate? +
A share certificate is a credit union's version of a bank CD (certificate of deposit). You deposit money for a fixed term at a fixed APY. Credit unions often offer higher rates than banks because they are member-owned non-profits that return earnings to members.
Are share certificates safe? +
Yes. Share certificates at federally-insured credit unions are insured by the NCUA up to $250,000 per depositor — equivalent to FDIC insurance at banks. Always verify your credit union is NCUA-insured before depositing.
What happens if I withdraw early? +
Early withdrawal penalties typically range from 90 to 180 days of interest depending on the term length. Some credit unions offer "no-penalty" share certificates that allow early withdrawal without fees — useful if you might need access to the funds.
How often is share certificate interest compounded? +
Most share certificates compound daily or monthly. Daily compounding yields slightly more than monthly. The calculator defaults to daily compounding, which is standard at most credit unions.
What is the difference between APY and APR? +
APY (Annual Percentage Yield) includes the effect of compounding — it reflects your actual annual earnings rate. APR (Annual Percentage Rate) does not include compounding. Always compare APY when shopping for share certificates to get an apples-to-apples comparison.