CD Calculator

Calculate the maturity value and interest earned on a certificate of deposit.

CD maturity valueInterest and APYUpdated May 2026

Certificate of Deposit Calculator

Enter your deposit, rate, term, and optional penalty or tax assumptions.

Currency

Initial deposit is the amount placed into the CD.

APY already reflects compounding.

Use APY if your bank quotes annual percentage yield.

Compounding affects growth when using a nominal interest rate.

Term length is how long the money stays locked before maturity.

Optional extra amount included at the start of the CD estimate.

Enter estimated penalty as months of interest. Leave 0 if not estimating early withdrawal.

Optional estimate. Actual tax treatment varies.

Estimated maturity value

£10,500.00

Based on your inputs for a 1 year CD.

Interest earned

£500.00

Maturity value minus principal.

Initial deposit

£10,000.00

Original amount placed into the CD.

Starting principal

£10,000.00

Initial deposit plus additional deposit.

CD term

1 year

12 total month(s).

APY used

5.00%

Compounding already reflected.

Effective growth

5.00%

Interest earned as a share of starting principal.

Penalty impact

£0.00

Estimated from months of interest entered.

Estimated tax

£0.00

Based on tax rate input.

Estimated after-tax value

£10,500.00

After estimated penalty and tax.

CD returns depend on APY, term, and whether interest is compounded or withdrawn.
Updated May 2026Formula verifiedReviewed for accuracy

Savings-focused

Estimate how much your deposit could grow by maturity based on the rate and term you enter.

Banking assumptions

Rates, compounding, penalties, and renewal rules vary by bank and account terms.

Planning support

Compare terms, APY assumptions, and liquidity trade-offs before locking money away.

Dynamic CD Insights

Your CD could grow to about £10,500.00 by maturity, based on your inputs.
You would earn approximately £500.00 in interest over 1 year.
The maturity value includes your original deposit plus earned interest.
A longer CD term may earn more interest, but it can reduce access to your cash.
Because APY is selected, compounding is already reflected in the rate.
No early withdrawal penalty is included unless you enter a penalty assumption.

What a CD Is

Certificate of deposit

CD stands for certificate of deposit, a savings product offered by banks and credit unions.

Fixed term

CDs usually pay a fixed rate for a fixed period, such as 6 months, 1 year, or 5 years.

Locked funds

Money is typically locked until maturity unless you accept an early withdrawal penalty.

Savings goals

CDs are often used for planned savings goals where the money is not needed immediately.

Penalty rules

Early withdrawals may reduce earnings depending on the bank and CD term.

Maturity decision

At maturity, you may be able to withdraw, renew, or move the funds elsewhere.

APY, Interest Rate, and Compounding

Interest rate

The interest rate is the stated annual rate before fully reflecting compounding. When using a nominal rate, compounding frequency affects the maturity value.

APY

APY reflects compounding over one year. If APY is entered, avoid double-counting compounding as if it were a nominal rate.

CD Term Length and Maturity Value

Term length controls how long your money earns the CD rate. A 6-month CD, 1-year CD, and 5-year CD can produce very different maturity values even with the same deposit.

Maturity value is the final estimated balance at the end of the term. It includes the original principal plus interest earned from the assumptions you enter.

Longer terms may offer different rates, but they also reduce flexibility. Renewal and rollover choices matter when the CD reaches maturity.

Early Withdrawal Penalties and Liquidity

Less liquid than savings

CDs are typically less flexible than regular savings accounts because funds are locked for a fixed term.

Penalty risk

Early withdrawal penalties may reduce or eliminate interest if funds are withdrawn before maturity.

Bank rules vary

Penalty rules vary by bank, CD type, and term length.

Review terms first

Review account terms before opening a CD or assuming access to funds.

CD Ladder Strategy

Split deposits

A CD ladder divides money across multiple CDs with different maturity dates.

Balance access

Shorter CDs mature sooner, giving more regular access to cash.

Rate flexibility

Longer CDs may offer different rates but can lock money away for longer.

Reduce timing risk

Laddering can reduce the risk of locking all funds into one rate and one maturity date.

Practical planning

A ladder may help match savings to future spending dates.

No product advice

This is a planning concept, not a recommendation for a specific CD or bank.

CD Calculator Formula

Maturity Value = Principal × (1 + r / n)n × t

Used for a nominal annual interest rate.

Interest Earned = Maturity Value − Principal

Shows the amount earned above the original deposit.

Maturity Value = Principal × (1 + APY)t

Used when APY is entered because compounding is already reflected.

Principal = initial deposit plus optional additional deposit
r = annual nominal interest rate
n = compounding periods per year
t = term in years
APY = annual percentage yield
Taxes and penalties are estimates when entered

Formulas may differ when additional deposits, taxes, or early withdrawal penalties are included. APY should not be compounded again as if it were a nominal interest rate.

Frequently Asked Questions