Three inputs, one guaranteed return
A fixed-term deposit locks your money for a set period at a guaranteed interest rate. Unlike stocks or funds, the return is predictable from day one. This calculator takes your deposit amount, the quoted annual rate and the term length, then shows gross interest, net interest after withholding tax, the effective annual yield and - optionally - whether your return beats inflation.
Key number
$10,000 at 5% for 12 months = $425 net
After 15% withholding tax. Gross interest: $500.
How to use this calculator
1
Deposit amount - the principal you want to lock in. Most banks require $500-$1,000 minimum for a CD or fixed deposit.
2
Annual interest rate - the APR your bank offers. High-yield savings: 4-5%. 12-month CD: 4.5-5.5%. Compare offers from several banks before committing.
3
Deposit term - from 1 month to 3 years. Longer terms sometimes pay higher rates, but your money is locked for the duration.
4
Compounding - "at maturity" means one lump sum at the end. Monthly compounding adds interest to the balance each month, producing a slightly higher total.
5
Inflation (optional) - enter the current rate to see if your deposit preserves purchasing power or falls behind.
How much does a $10,000 deposit earn?
Net interest after 15% withholding tax, compounded at maturity.
| Term |
At 4% |
At 5% |
At 5.5% |
| 3 months |
$85 |
$106 |
$117 |
| 6 months |
$170 |
$213 |
$234 |
| 12 months |
$340 |
$425 |
$468 |
| 24 months |
$693 |
$871 |
$961 |
Three deposit scenarios
Emergency fund: $20,000 for 6 months at 5%
Gross interest: $500. After 15% tax: $425 net. You earn roughly $71/month while keeping the fund accessible after 6 months. A high-yield savings account might offer 4.2% with no lock-in - the $40 difference is the price of liquidity.
Short-term parking: $50,000 for 3 months at 5.25%
Gross interest: $656. Net: $558. Useful when you need the money in 90 days (e.g. a down payment closing) and want a guaranteed return in the meantime.
Long lock-in: $30,000 for 24 months at 5% vs 3.5% inflation
Net interest: $2,614. Inflation erodes $2,137 of purchasing power over 2 years. Real gain: $477. The deposit beats inflation, but barely. At 5% inflation, real return turns negative.
Practical examples
$5,000 at 4.5% for 6 months (at maturity) - gross: $113, tax: $17, net: $96.
$25,000 at 5% for 12 months (monthly compounding) - gross: $1,279, tax: $192, net: $1,087. Monthly compounding adds $29 vs at-maturity.
$100,000 at 4% for 3 months - gross: $1,000, tax: $150, net: $850. That is $283/month guaranteed.
$10,000 at 5.5% for 36 months (quarterly compounding) - gross: $1,756, tax: $263, net: $1,493.
$2,000 at 4% for 1 month - gross: $7, tax: $1, net: $6. Short terms on small amounts yield very little.
FAQ - Frequently asked questions
What is the withholding tax on deposit interest?
In many countries, banks withhold a flat tax on interest income before paying you. The rate varies: 15% in the US (federal, may vary by state), 19% in Poland, 20% in the UK (for non-ISA accounts), 26.375% in Germany. This calculator uses 15% as a default. Your actual rate depends on your tax jurisdiction and whether the account qualifies for any exemptions (like a US IRA or UK ISA).
Fixed deposit vs high-yield savings - which is better?
A fixed deposit (CD) locks your money for a set term but guarantees the rate for the full duration. A high-yield savings account lets you withdraw anytime but the rate can change monthly. If rates are falling, locking in a CD protects your return. If rates are rising, a savings account lets you benefit from increases. For emergency funds, savings accounts win on flexibility. For money you will not need for 6-12 months, a CD often pays 0.3-0.5% more.
Does compounding frequency matter for deposits?
Yes, but the effect is modest. On a $10,000 deposit at 5% for 12 months: at maturity yields $500 gross; monthly compounding yields $512 gross - a $12 difference. The gap grows with larger amounts and longer terms. For a 24-month deposit, the difference rises to roughly $50. Always check which option your bank offers.
What happens if I withdraw early?
Most fixed deposits charge an early withdrawal penalty, typically 60-180 days of interest. Some banks forfeit all interest on early breaks. A few offer "no-penalty CDs" with slightly lower rates. Before committing, check the penalty terms. If you might need the money, consider a shorter term or a ladder strategy (splitting across 3, 6 and 12-month deposits).
What is the effective annual rate?
The effective annual rate (EAR) accounts for compounding and tax. A deposit quoting 5% nominal with monthly compounding actually earns 5.12% annually before tax. After 15% tax, the effective net rate drops to about 4.35%. The calculator shows this number so you can compare deposits on equal footing, regardless of their compounding frequency.
Can a deposit lose money to inflation?
A deposit never loses nominal value - you always get back your principal plus interest. But in real terms (purchasing power), yes. If your net return is 4.25% and inflation is 5%, you lose roughly 0.75% of purchasing power per year. The inflation field in this calculator shows exactly how much. During high-inflation periods, deposits are a capital preservation tool, not a growth tool.
Related tools
Loan Payment Calculator
Compare fixed vs declining loan instalments and see total interest cost - See calculator
Compound Interest Calculator
Calculate long-term growth with compound interest and regular contributions - See calculator
Currency Converter
Convert between 10 major currencies with daily mid-market rates - See calculator
Bitcoin & Crypto Calculator
Convert BTC, ETH and other cryptocurrencies to USD with live prices - See calculator