Compound Interest Calculator
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Where the money comes from
- Starting balanceToday$10,000
- Total deposits$200 a month, at the end of each month+$24,000
- Interest earned4.50% compounded monthly (4.59% APY)+$11,910
- Ending balanceAfter 10 years · $31,924 in today's dollars$45,910
Millions of savers keep money in accounts paying a fraction of a percent while online banks and credit unions pay ten times more for the same federal insurance. Moving savings from an average account to a top one changes this result more than compounding frequency, deposit timing or almost any other setting here.
$10,000 plus $200 a month at 4.50% compounded monthly grows to $45,910 in 10 years — $11,910 of it interest. In today's dollars, after 3.7% inflation, that is about $31,924.
- Your money doubles about every 15.4 years at 4.59% APY. That beats inflation of 3.7%, so your buying power grows too.
- Enter a goal to see the monthly savings it takes to get there in 10 years.
- Keep savings in FDIC- or NCUA-insured accounts up to $250,000 per depositor, per bank, per ownership category. Interest is taxable unless it's in an IRA, 401(k) or similar account.
Key Answers About Your Savings
Each answer is recalculated from your entries above.
About $45,910 after 10 years. You put in $34,000 and earn $11,910 in interest — 26% of the final balance. Waiting five years to start would leave you with $25,947 instead.
Enter a savings goal in the calculator and this answer will show the monthly amount needed to reach it in 10 years at 4.50%.
At 3.7% inflation, $45,910 in 10 years buys what about $31,924 buys today. Your rate beats inflation by 0.80% a year, so your buying power grows. The latest 12-month inflation rate from the Bureau of Labor Statistics was 3.7% as of mid-October 2026.
As of mid-October 2026, the average savings account paid about 0.37% and the average one-year CD 1.73%, while the best high-yield savings accounts paid around 4.50% and top one-year CDs 4.75%. Moving money from an average account to a top one is often the single biggest improvement you can make.
Less than most people expect. At 4.50%, daily compounding gives an APY of 4.602% and yearly compounding 4.50%. Compare accounts by APY, which already includes compounding — the rate itself matters far more than how often it compounds.
Divide 72 by the interest rate to estimate how long money takes to double. At 4.50%, that is about 16.0 years; the exact answer at 4.59% APY is 15.4 years. The same rule shows how fast inflation halves buying power: at 3.7%, in about 19 years.
Your Savings at Today's Rates
The same plan at typical rates as of mid-October 2026.
| Where | Rate | Result |
|---|---|---|
| Average savings account | 0.37% | $34,823 |
| Average 1-year CD | 1.73% | $38,068 |
| Top high-yield savings | 4.50% | $45,910 |
| Top 1-year CD | 4.75% | $46,710 |
| 10-year Treasury | 5.08% | $47,792 |
| Stocks, long-run average | 10.00% | $68,039 |
A point or two higher or lower
| Rate | Result | Total interest |
|---|---|---|
| 2.50% | $40,071 | $6,071 |
| 3.50% | $42,870 | $8,870 |
| 4.50% yours | $45,910 | $11,910 |
| 5.50% | $49,212 | $15,212 |
| 6.50% | $52,802 | $18,802 |
The stock-market figure is a long-run average — about 10% a year before inflation since 1926 — not a steady rate. Stocks have lost a third or more of their value several times, sometimes for years. Money you'll need within about five years usually belongs in insured savings, CDs or Treasuries instead.
Year-by-Year Balance
| Year | Total deposits | Interest | Balance |
|---|---|---|---|
| 1 | +$2,400 | +$510 | $12,910 |
| 2 | +$2,400 | +$643 | $15,953 |
| 3 | +$2,400 | +$783 | $19,136 |
| 4 | +$2,400 | +$929 | $22,465 |
| 5 | +$2,400 | +$1,082 | $25,947 |
| 6 | +$2,400 | +$1,242 | $29,589 |
| 7 | +$2,400 | +$1,409 | $33,399 |
| 8 | +$2,400 | +$1,584 | $37,383 |
| 9 | +$2,400 | +$1,767 | $41,551 |
| 10 | +$2,400 | +$1,959 | $45,910 |
Daily vs Monthly vs Yearly Compounding
| Compounding | APY | Ending balance |
|---|---|---|
| Daily | 4.602% | $45,935 |
| Monthly yours | 4.594% | $45,910 |
| Quarterly | 4.577% | $45,856 |
| Yearly | 4.500% | $45,625 |
Compound interest means you earn interest on your interest. The more often it's added, the slightly higher the yield — but the difference between daily and monthly compounding is usually a few dollars a year. Banks must show the annual percentage yield (APY), which already includes compounding, so compare accounts by APY.
What to Do in Your Situation
Switch to "How long will my savings last?" and enter your monthly withdrawal, raising it each year by inflation. If the money runs out sooner than you'd like, waiting to claim Social Security, trimming withdrawals by even a few percent, or keeping a few years of spending in safe accounts can all stretch it.
Online banks and credit unions often pay many times the national average, with the same FDIC or NCUA insurance up to $250,000 per depositor, per bank, per ownership category. Check the rate on your current account — many big banks still pay close to nothing.
CDs and Treasury securities fix your rate for a set term, which protects you if rates fall. A CD "ladder" — splitting money across 1-, 2- and 3-year CDs — keeps some cash coming due every year. Watch early-withdrawal penalties before you commit money you might need.
Interest from savings, CDs and bonds is taxed as ordinary income each year (Treasury interest is exempt from state and local tax). Growth inside an IRA, Roth IRA or 401(k) isn't taxed until withdrawal — or ever, for qualified Roth withdrawals. This calculator shows results before tax.
How This Calculator Works
The calculator works month by month. Your yearly rate is converted to an equivalent monthly rate for the compounding you choose — (1 + rate ÷ n)n/12 − 1, where n is 365, 12, 4 or 1 — and interest is added each month on the balance. Deposits or withdrawals happen at the start or end of each month and can rise by a fixed percentage each year. In draw-down mode, the balance stops at zero and the calculator reports when that happens.
"Today's dollars" divides the ending balance by (1 + inflation)years. APY is (1 + rate ÷ n)n − 1. The monthly amount to reach a goal, or to spend the account down over the term, uses the standard annuity formula with the same monthly rate. Results are estimates before taxes and fees.
This calculator is for education and planning only and isn't financial, tax or investment advice. Rates change often; the quick rates reflect national averages and leading offers as of mid-October 2026. Investment returns are not guaranteed. BudgetSeniors.com is not a bank, broker or adviser.
Key sources: FDIC national rates · U.S. Bureau of Labor Statistics Consumer Price Index · U.S. Treasury · bank rate surveys (NerdWallet, Fortune) · historical S&P 500 returns · SEC Investor.gov