Savings Account Calculator: Balance or Time to a Goal

How the savings figures are calculated

The calculator uses your APY, the annual percentage yield shown on your account. It moves forward one month at a time.

Find one month of growth. A year at the APY is split into 12 equal steps.
Monthly growth = (1 + APY)^(1/12)
Grow the balance, then add the deposit.
New balance = old balance × monthly growth + monthly deposit
"How much will I have" mode. Repeat step 2 for every month in the period. The interest is the final balance minus everything you paid in.
"How long to reach my goal" mode. Repeat step 2 until the balance reaches the goal, and count the months. The calculator also counts the months with no interest at all, so you can see how much time the interest saves.

If you enter an inflation rate, the final balance is divided by (1 + inflation) for each year. That gives its buying power in today's prices.

Worked examples

The APYs below are examples to show the maths. They are not rates on offer.

$2,000 plus $200 a month for 5 years at 3% APY

The calculator's starting numbers. Most of the final balance is money paid in.

Starting balance$2,000
Monthly deposits (60 × $200)$12,000
Interest earned$1,235
Share of the balance that is interest8.1%
Balance at the end$15,235

Building a $15,000 emergency fund

Starting with $1,000 and adding $350 a month at 3.5% APY. This uses the goal mode.

Goal$15,000
Still to save at the start$14,000
Deposits added on the way$13,300
Interest earned on the way$846
Time with deposits only, no interest3 years 4 months
Time to reach the goal3 years 2 months

$20,000 left for 10 years at 2% APY, with 3% inflation

No deposits. The balance goes up, but prices go up faster, so the money buys less than $20,000 does today.

Starting balance$20,000
Monthly deposits (120 × $0)$0
Interest earned$4,380
Share of the balance that is interest18.0%
Buying power in today's prices (3% inflation)$18,141
Balance at the end$24,380

How long it takes to save $10,000

Starting from zero, this is the time to reach $10,000 at different monthly deposits. The first column of results has no interest, so you can see what the APY adds.

Time to reach $10,000 from a zero balance, counting whole months. The APYs are examples, not current rates.
Monthly deposit	No interest	2% APY	4% APY
$100	8 years 4 months	7 years 9 months	7 years 3 months
$150	5 years 7 months	5 years 4 months	5 years 1 month
$200	4 years 2 months	4 years 1 month	3 years 11 months
$250	3 years 4 months	3 years 3 months	3 years 2 months
$300	2 years 10 months	2 years 9 months	2 years 8 months
$400	2 years 1 month	2 years 1 month	2 years 1 month
$500	20 months	20 months	20 months
$750	14 months	14 months	14 months
$1,000	10 months	10 months	10 months

The larger the deposit, the less the rate matters, because the money is not in the account long enough to earn much. Small deposits over many years are where interest saves the most time.

To work the other way, this table shows the monthly deposit needed to hit a goal by a set date.

Monthly deposit needed, starting from zero, at an example APY of 3%.
Goal	In 1 year	In 2 years	In 3 years	In 5 years
$5,000	$411	$202	$133	$77
$10,000	$822	$405	$266	$155
$20,000	$1,644	$810	$532	$310
$50,000	$4,110	$2,025	$1,330	$774

How savings interest is taxed

Interest on a savings account is taxable income. The IRS counts it in the year it becomes available to you, which for a savings account is when it is credited, whether or not you take it out.

It is ordinary income. It is added to your wages and other income and taxed at your usual federal rates.
Form 1099-INT. Your bank sends one when it pays you $10 or more of interest in the year.
You report all of it. The IRS says you must report all taxable interest even if you do not receive a form.
Schedule B. If your taxable interest is more than $1,500, you list it on Schedule B of Form 1040.

As a rough guide, $10,000 at 3% APY earns $300 in a year. At a 22% federal tax rate, about $66 of that goes in tax. The calculator does not deduct tax because the rate depends on your other income, and your state may tax interest too.

FDIC and NCUA insurance

A savings balance at an FDIC-insured bank is insured up to $250,000. At a federally insured credit union the National Credit Union Share Insurance Fund gives individual accounts the same $250,000 of cover. Two details matter when you are saving toward a goal.

Your accounts are added together. Savings, checking, money market deposit accounts and CDs that you hold at one bank in the same ownership category share one limit.
Interest counts too. Cover includes interest that has built up, so a balance that starts under $250,000 can grow past it. If your goal is above the limit, the part over it at one bank in one ownership category is not insured.

Insurance protects against the bank failing. It does not cover stocks, bonds or mutual funds, even when a bank sells them.

Inflation and buying power

Inflation is the rise in prices over time. It does not take dollars out of your account, but each dollar buys less. The US Securities and Exchange Commission says the principal concern with cash-type holdings is that inflation will erode returns.

The test is whether your APY is above or below inflation. Consumer prices rose 3.4% in the 12 months to August 2026, according to the Bureau of Labor Statistics. At that pace, $10,000 left for five years at an example APY of 3% grows to $11,593 but buys only what $9,808 buys today.

Nobody knows future inflation, and one year's figure is not a forecast. Try the calculator with a lower and a higher rate than today's to see how much the answer moves.

What the result leaves out

Rate changes. One APY is used throughout. Unless your account has a fixed rate, the bank can change it.
Tax on the interest. Not deducted.
Fees and minimum balances. A monthly fee or a balance requirement can lower what you earn.
Withdrawals. The sums assume money only goes in. The old federal limit of 6 withdrawals a month was removed in April 2020, but your bank may still set a limit or charge a fee.
Exact dates. Deposits are counted at the end of each month, and the goal mode counts whole months.

Common mistakes

Waiting for a better rate before starting. Over a year or two, an extra month of deposits adds more than an extra point of APY on a small balance.
Treating the result as a promise. It is an estimate at a rate that may not last.
Forgetting tax. If you pay the tax from the same account, the balance will be lower than shown.
Setting a goal in today's prices for a date years away. If the goal is a purchase, its price will probably rise. Use the inflation box to see by how much.
Assuming everything is insured. Cover stops at $250,000 per depositor, per bank, per ownership category.

Questions people ask

How long will it take to save $10,000?

Starting from zero, $200 a month takes 4 years 2 months with no interest and 3 years 11 months at an example APY of 4%. At $500 a month it takes 20 months.

How is savings account interest calculated?

The bank applies a daily or periodic rate to your balance and adds the interest to the account on the schedule in its disclosures. The APY tells you the total effect over a year, so a balance left alone grows by the APY in 12 months.

Is savings account interest taxable?

Yes. It is taxable income in the year it becomes available to you, and it is taxed as ordinary income. Banks send Form 1099-INT when interest is $10 or more, but you must report all of it either way.

Do I pay tax on interest under $10?

Yes. The $10 figure is when the bank must send a form. The IRS says you must report all taxable interest on your return even if you do not receive one.

Is my savings account insured?

At an FDIC-insured bank, deposits are insured up to $250,000 per depositor, per insured bank, for each account ownership category. Federally insured credit unions have the same $250,000 cover through the National Credit Union Share Insurance Fund.

Can I only make six withdrawals a month from a savings account?

Not under federal rules. The Federal Reserve deleted the limit of 6 transfers and withdrawals a month from its Regulation D in April 2020. A bank can still set its own limit or charge a fee, so check your account terms.

Does inflation reduce my savings?

It does not reduce the number of dollars, but it reduces what they buy. If prices rise faster than your APY, your balance grows while its buying power falls.

Should I enter the APY or the interest rate?

Enter the APY. It already includes compounding, which is why this calculator does not ask how often interest is compounded.

Will my savings rate stay the same?

Not necessarily. With a variable-rate account the bank can change the rate after you open it, and its disclosures must say that the interest rate and APY may change. Rerun the numbers when your rate moves.

Sources

Figures last checked against these sources on October 10, 2026. This page gives general information and estimates, not tax, legal or financial advice.