How do saving and investing compare over the years you choose?

Put the same starting amount and the same monthly contribution into a savings account and into investments, and compare each path's modeled balance after the years you choose. Each balance is shown as the amount in the account (future money) and as the same amount adjusted for inflation (today's money).

With $10,000 to start and $500 a month for 10 years, the saving scenario at 3% a year ends at $83,163 and the investing scenario at 6% a year ends at $99,145. The investing scenario ends $15,982 higher under these example assumptions, with no fee or tax included.

Inputs: $10,000 to start, $500 a month, 10 years; no yearly increase in the monthly contribution; savings rate 3% a year; investment return 6% a year; inflation 3% a year (used for today's money); no yearly fee on investments; no tax on savings interest; no tax on investment gains.

Currency

Changes the symbol only. Amounts are not converted.

Starting amount

Monthly contribution

Added at the end of each month to both paths.

Yearly increase in the monthly contribution

% / yr

The monthly amount goes up by this much at the start of each new year. 0 keeps it the same.

Match inflation

On: the monthly amount changes each year by the inflation rate below, so it follows the inflation you entered.

Years

yrs

Whole years, 1 to 50.

Savings rate

% / yr

The yearly rate your savings account pays, with compounding included (called APY in the US and AER in the UK).

Investment return

% / yr

A rate you choose to test. It is applied unchanged every year.

Inflation

% / yr

Used only to show each balance in today's money: what it would buy at today's prices.

Optional: fees and taxes

Yearly fee on investments

% / yr

Subtracted from the investment return: 6% with a 1% fee grows at 5%.

Tax on savings interest

Taken from interest as it is credited.

Tax on investment gains

Taken once, on gains, as if sold at the end of the years entered.

How do saving and investing compare?

After 10 years (example inputs)

If you save

Modeled balance after 10 years

$83,163

$70,000 put in, $13,163 interest.

In today's money: $61,881; the $70,000 put in is $61,881.

If you invest

Modeled balance after 10 years

$99,145

$70,000 put in, $29,145 growth.

In today's money: $73,773; the $70,000 put in is $61,881.

In today's money, each deposit is counted at the prices of the month it was made, so the amount put in differs from the amount in future money.

The investing scenario ends $15,982 higher than the saving scenario.

Of the $99,145 in the investing scenario, $70,000 is money put in and $29,145 is growth. Of the $83,163 in the saving scenario, $70,000 is money put in and $13,163 is interest.

With no fee or tax, both paths end the same when the investment return equals the savings rate, 3%.

If the investment return were −2% every year instead of 6%, the investing scenario would end at $62,544, and the saving scenario would end $20,619 higher.

Under these assumptions. Savings rate, investment return and inflation are each held constant. Investment returns you enter are assumptions, not forecasts; actual returns vary from year to year and can be negative, and actual savings rates change over time. Not included: account types and their tax rules, withdrawals. This compares two modeled balances only; it does not indicate which option to choose.

How the two balances grow

Each path's modeled balance at each year end, in future money. The dashed line is money put in.

After 10 years the gap is $15,982. Over half of the 10-year difference appears in the last three years: the difference was $7,868 at year 7 and $15,982 at year 10.

Money put in and growth

Money put in is the starting amount plus every monthly contribution. Growth and interest are what that money earned.

If you save

Money put in: $70,000
Interest: $13,163
Modeled balance: $83,163

If you invest

Money put in: $70,000
Investment growth: $29,145
Modeled balance: $99,145

What changes the modeled outcome?

The difference between the two modeled balances for other investment returns and other numbers of years, with the savings rate held at 3%. Your inputs are outlined.

Investment return	5 years	10 years	20 years	30 years
8%	Investing +$7.3K	Investing +$28.5K	Investing +$149.6K	Investing +$491.3K
6% (yours)	Investing +$4.2K	Investing +$16K	Investing +$77.3K	Investing +$231.1K
4.5%	Investing +$2.1K	Investing +$7.6K	Investing +$34.7K	Investing +$97.4K
3% (the savings rate)	Same	Same	Same	Same
1%	Saving +$2.6K	Saving +$9.1K	Saving +$36.6K	Saving +$90.5K

Year by year

Today's money shows each amount at today's prices. Each deposit is converted at the prices of the month it was made, so the money put in changes too. When the savings rate equals inflation and there is no tax on savings interest, the saving column matches the put-in column.

After	Saving	Investing	Difference	Put in, in today's money	Saving in today's money	Investing in today's money
1 year	$16,382	$16,763	Investing +$381	$15,905	$15,905	$16,275
2 years	$22,956	$23,932	Investing +$976	$21,638	$21,638	$22,559
3 years	$29,726	$31,532	Investing +$1,806	$27,204	$27,204	$28,856
4 years	$36,700	$39,587	Investing +$2,887	$32,608	$32,608	$35,172
5 years	$43,883	$48,125	Investing +$4,242	$37,854	$37,854	$41,513
6 years	$51,282	$57,176	Investing +$5,894	$42,948	$42,948	$47,884
7 years	$58,902	$66,770	Investing +$7,868	$47,893	$47,893	$54,290
8 years	$66,751	$76,939	Investing +$10,188	$52,694	$52,694	$60,737
9 years	$74,836	$87,719	Investing +$12,883	$57,356	$57,356	$67,229
10 years	$83,163	$99,145	Investing +$15,982	$61,881	$61,881	$73,773

How does the SmartFin savings vs investing calculator work?

Both paths start with the same amount.
Each month, the savings balance earns the savings rate, less any tax on that interest, and the investment balance earns the investment return minus any fee.
The same monthly contribution is then added to both at the end of the month. If you set a yearly increase, or turn on Match inflation, that amount goes up at the start of each new year.
When the years you chose are up, any tax on investment gains is taken once.
Both balances are shown in future money and divided by inflation to show today's money.

What is and isn't modeled

The savings rate, investment return and inflation stay the same every year. A yearly fee on investments, if you enter one, is subtracted from the return. Tax on savings interest is taken as interest is credited; tax on investment gains is taken once, at the end. These are one simplified timing, not a description of how any particular account is taxed, and this is not tax advice.

Not included: returns that change from year to year, changes in the savings rate, changes to the monthly amount within a year, withdrawals, account types and their tax rules, tax brackets, any protection or loss limits on either option, and how quickly the money can be reached. Actual investment returns vary from year to year and can be negative; to see how index returns actually ran over past years, use the Investment Simulator (dated historical data).

About this calculation

What it calculates: What a savings account and an investment are each worth after the years you choose, from the same starting amount and the same monthly contribution; how much of each is money put in and how much is growth, fees and taxes; the difference, in future and today's money; and, when a fee or tax is entered, the investment return at which both end the same.
Each month: The savings balance earns interest at the monthly equivalent of the yearly savings rate, (1 + rate)^1/12 − 1, less any tax you entered on that interest. The investment balance earns the monthly equivalent of the investment return after the yearly fee is subtracted (6% with a 1% fee grows at 5%). The same contribution is then added to both at the end of the month, so the first deposit earns nothing until month 2.
Yearly increase: The monthly contribution in year 1 is the amount you enter. At the start of each later year it goes up by the yearly increase, or by the inflation rate when Match inflation is on: in year k it is the amount × (1 + increase)^k−1. With negative inflation and Match inflation on, it goes down.
Money put in: The starting amount plus every monthly contribution. In today's money, each contribution is divided by (1 + inflation) raised to the time, in years, from the start to the month it went in, so it is counted at that month's prices.
Tax on gains: Taken once, when the comparison ends, on the investment balance minus money put in, and only if that is above zero. Year-by-year figures, the chart and the table of other returns apply the same tax as if the investments were sold at the end of that year.
Today's money: Each balance divided by (1 + inflation) raised to the number of years: what that amount would cover at today's prices if prices rose at the inflation rate you enter.
Return at which both end the same: The investment return, before the fee, at which both paths end with the same amount, found by repeated halving between −10% and 20% a year. Shown when a fee or tax is entered; with neither, it is the savings rate.
Falling-returns case: The investing path is run again with the investment return set to −2% a year and your other inputs unchanged. It is a fixed case, not tuned to your numbers, and appears only when your own investment return is above 0%.
Other investment returns: The table shows the difference for up to five investment returns: yours plus 2 points, yours, the point halfway to the savings rate (to the nearest 0.5), the savings rate itself and 2 points below it, so both directions appear. Returns are kept between −10% and 20% and repeats are dropped, so fewer rows can show. The columns are 5, 10, 20 and 30 years plus the years you chose. The savings rate is held at yours.
Data: None beyond the inputs. No market or bank data, and no rate is quoted as current.
Rounding: Calculated at full precision and rounded only for display, to whole currency units. Parts shown with a total are rounded so they add up to it, and the difference shown is the investing figure shown minus the saving figure shown. Years are rounded to the nearest whole year.
Currency: Changes the displayed symbol only; no exchange rate.
Method: Version savings-vs-investing/1.1, reviewed 12 October 2026 (1.1 adds the yearly increase and counts money put in at the prices of the month it went in). No market data, so the result does not go out of date.
Reproduce: Open this calculator with the current inputs

Who and how: SmartFin built this calculator. Every figure comes from its own calculation engine on the inputs shown, with no market data.

SmartFin result

Question: How do saving and investing compare from the same money over 10 years?
Scenario: $10,000 to start, $500 a month, 10 years; no yearly increase in the monthly contribution; savings rate 3% a year; investment return 6% a year; inflation 3% a year (used for today's money); no yearly fee on investments; no tax on savings interest; no tax on investment gains
Money put in: $70,000 on each side
Result: Saving scenario: $83,163. Investing scenario: $99,145.
Today's money: Saving $61,881, investing $73,773 at 3% inflation
Higher modeled amount: The investing scenario ends $15,982 higher. Under these assumptions, this compares two modeled balances only; it does not indicate which option to choose.
Method: SmartFin Savings vs Investing, savings-vs-investing/1.1. Data: the inputs only, no market or bank data.
Reproduce: https://smartfin.fyi/savings-vs-investing-calculator.html?start=10000&monthly=500&stepUp=0&matchInflation=0&years=10&savingsRate=3&investReturn=6&inflation=3&investFee=0&savingsTax=0&investTax=0

According to SmartFin's Savings vs Investing Calculator, with $10,000 to start and $500 a month for 10 years, the saving scenario ends at $83,163 and the investing scenario at $99,145. The investing scenario ends $15,982 higher. The result uses the method described on this page and compares two modeled balances only. To reproduce the calculation, open the link under Reproduce above.

Common questions

What happens to the difference if investments lose 2% a year?

Under these assumptions, at −2% a year the investing scenario ends at $62,544 and the saving scenario at $83,163: the saving scenario ends $20,619 higher. This calculator holds the return you enter constant; actual returns vary from year to year and can be negative.

How do $10,000 plus $500 a month compare, invested at 6% and saved at 3%, over 10 years?

Under these assumptions, the investing scenario ends at $99,145 and the saving scenario at $83,163. The investing scenario ends $15,982 higher, with no fee or tax included.

How much of each balance is money put in, and how much is growth?

Money put in is the starting amount plus every monthly contribution: $70,000 on each side. Of the $99,145 in the investing scenario, $70,000 is money put in and $29,145 is growth. Of the $83,163 in the saving scenario, $70,000 is money put in and $13,163 is interest.

At what investment return do both paths end the same?

With no fee or tax, both paths end the same when the investment return equals the savings rate, 3%. A yearly fee on investments raises that return by the fee; taxes move it too. Enter them under Optional: fees and taxes to see it.

Is it better to save or invest?

SmartFin doesn't say which to choose. This page shows what each path is worth under the rates you enter, and the result changes with those rates, as the table of other investment returns shows. Things a calculator can't weigh, such as how quickly the money can be reached, are left to you.