Saving
Deposit and savings interest calculator
Calculate compound deposit interest after entered tax and withdrawal penalties. Compare a single deposit with an equally funded deposit ladder.
Content updated . Assumptions reviewed .
Your inputs
Showing the example. Edit your inputs, then calculate.
Ending deposit balance
10,407.42 USD
Ending balances include the entered tax rate and any early-withdrawal penalty. Matured ladder proceeds stay in cash.
- Principal
- 10,000
- Gross Interest
- 407.42
- Total Tax
- 0
- Total Penalty
- 0
- Net Interest
- 407.42
- Annual Percentage Yield
- 4.07
- Ladder Rungs
- 1
Illustrative result from your inputs and the dated assumptions shown; not a forecast, recommendation or offer
KlarFort is not financial, investment, tax, or legal advice. Verify outputs before making material decisions. Read the disclaimer.
Personal and commercial use is free with credit to KlarFort. See usage and credit.
About this calculator
Estimate interest and the ending balance for a fixed-rate deposit using your chosen compounding frequency. Include an entered tax rate and a penalty if you plan to withdraw before maturity.
Ladder mode splits the starting principal equally across deposits with staggered maturities. You choose the spacing and rate change between rungs, rather than relying on assumed bank offers.
How to use this calculator
- Enter the deposit principal, nominal annual interest rate, compounding frequency and first maturity in months.
- Select a single deposit or a ladder. For a ladder, enter its rung count, maturity spacing and rate step.
- Enter tax on positive interest and any early-withdrawal month and penalty. A withdrawal month of zero means each deposit matures.
- Calculate and review gross interest, tax, penalties, net interest and each rung's ending balance.
Understand your result
The ending balance adds interest and subtracts modeled penalties and tax. Net interest can be negative when an early penalty reduces the original principal.
In a ladder, the result adds the proceeds from all rungs at their respective withdrawal or maturity dates. Proceeds from an earlier maturity remain cash and earn no additional modeled return.
Questions about this calculator
How is APR different from the annual percentage yield?
The nominal annual rate is divided across compounding periods. Annual percentage yield, or APY, includes the effect of compounding for a year. The displayed APY uses the first deposit's rate before tax and penalties.
How does an early-withdrawal penalty work here?
For a deposit withdrawn before maturity, the penalty equals the entered number of months of simple interest on its principal. It is capped at the available balance and can reduce principal.
Are ladder deposits reinvested when they mature?
No. The model holds matured proceeds as cash. Each rung receives an equal share of the original principal and uses the maturity and rate determined by your spacing and rate-step inputs.
Where do my figures go?
Your page calculations run in this browser. The API and connected assistants send the inputs supplied to them to our Cloudflare Worker. See Privacy.
How can I reproduce this result?
Use the same inputs and assumptions shown here. Simulation seeds reproduce the same paths. Read the calculation documentation.
Your calculation table
| Rung | Maturity Month | Withdrawal Month | Annual Rate | Principal | Gross Interest | Penalty | Tax | Ending Value |
|---|---|---|---|---|---|---|---|---|
| 1 | 12 | 12 | 4 | 10,000 | 407.42 | 0 | 0 | 10,407.42 |
Citable worked example
Deposit and savings interest calculator: fixed public worked-example outputs using the calculator’s published default inputs. Calculate compound deposit interest after entered tax and withdrawal penalties. Compare a single deposit with an equally funded deposit ladder. These illustrative figures are independent of visitor inputs and live market feeds. The table contains 1 rows and is available as CSV and JSON. Formula and assumptions reviewed 2026-09-07.
These are fixed public examples. Your calculation above does not change this table.
| Rung | Maturity Month | Withdrawal Month | Annual Rate | Principal | Gross Interest | Penalty | Tax | Ending Value |
|---|---|---|---|---|---|---|---|---|
| 1 | 12 | 12 | 4 | 10,000 | 407.42 | 0 | 0 | 10,407.42 |
Computed with KlarFort Calculators, https://klarfort.com/
Calculator reference: https://klarfort.com/tools/deposit-calculator/. Usage and credit.
Formula and assumptions
Gross interest = P ((1 + APR/f)^(f months/12) - 1).
- Fractional compounding periods use the same exponential convention; rates are fixed for each deposit.
- Ladder principal is split equally; rung maturities and rate steps are entered assumptions. Matured proceeds earn no further interest.
- Early penalties equal entered months of simple nominal interest and may reduce principal, capped at the account balance.
- Tax applies only to positive interest after the penalty, at the entered rate; no jurisdictional deductibility rules are assumed.
Assumptions reviewed:
Sources
- KlarFort calculator methodology. KlarFort-authored arithmetic; free to use with credit.; vintage 1.
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