Sumslip

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ROI calculator

Measure a finished investment that has one starting value and one ending value. Money added or removed in the middle needs a different tool.

$
$
years
Use decimals for part of a year. Three months is 0.25.

Results

Gain
$6,000.00
Simple return
60%
Compound annual rate
9.86%

How to use this page

  1. Replace the sample numbers with your own. Nothing is sent to a server.
  2. Read the result. It changes as you type.
  3. Open the formula if you want to recompute the result by hand.
  4. Copy the result if you want to keep it. The numbers you type stay in this browser and are not added to the address.

Formula

Gain = ending value − starting value. Simple return = gain ÷ starting value, shown as a percent. CAGR = (ending ÷ starting)^(1 ÷ years) − 1. A check: 100 growing to 121 in two years is a 21% simple return and a 10% compound annual rate, because 1.10 × 1.10 = 1.21.

Simple return is not a yearly rate

A 21% simple return over two years is not 21% a year. The compound annual rate spreads that result evenly across the years so you can compare a two-year flip with a five-year fund. Neither number includes fees you forgot to subtract from the ending value.

If the ending value is zero, the simple return is −100% and the compound rate is −100% as well. The page does not accept a negative ending value, because a negative asset value is a liability and belongs on a loan page only if it is actually a loan.

When CAGR is the wrong summary

CAGR assumes the only cash flows are the purchase and the sale. If you added money each month, a high CAGR can be an artifact of the timing. Use the compound-interest calculator for a deposit plan. Use this page after the investment is over and you know the two values.

Years can be fractional. One quarter is 0.25 years. Do not type 3 to mean three months.

Easy mistakes

  • Comparing a leveraged result with an unleveraged one as if the risk matched.
  • Leaving fees inside the ending value for one investment and subtracting them for another.
  • Using CAGR to forecast the next period. It describes the past path you typed, and it smooths out every crash in between.

Questions

Should the starting value include costs to buy?

Yes, if you want the return of cash you actually committed. Include commissions in the starting value or subtract them from the ending value, but do not do both.

Why does a short period make CAGR look wild?

A 10% gain in a month is a huge annualized rate because the formula asks what constant yearly pace would match that short jump. For short flips, read the simple return first.

Does this handle dividends?

Only if they are inside the ending value you type. The page has no separate dividend field. Reinvested dividends belong in the ending value. Cash dividends you spent should be added back if you want the total return.

Related tools

These figures are estimates you can recompute from the formula on the page. They are not a lender quote, a tax bill, a payroll statement, or financial advice.