Measure your portfolio's investment performance while
adjusting for deposits and withdrawals. Add dated cash
flows to estimate net investment gain, Modified Dietz
return, annualized return, and portfolio growth.
Enter Portfolio Details
Enter beginning and ending portfolio values,
measurement dates, and any external cash flows.
$
$
External Cash Flows
Positive amount = money deposited
into the portfolio.
•
Negative amount = money withdrawn
from the portfolio.
What Is a Portfolio Return Calculator?
A Portfolio Return Calculator estimates how much an
investment portfolio gained or lost during a selected
measurement period.
Simply comparing the beginning and ending balance can
be misleading when money was added to or withdrawn
from the portfolio during the period.
This calculator therefore lets you enter dated deposits
and withdrawals and estimates a cash-flow-adjusted
portfolio return using the Modified Dietz method.
How the Portfolio Return Calculator Works
1
Enter Portfolio Values
Add the value of your portfolio at the
beginning and end of the measurement period.
2
Add Cash Flows
Enter deposits and withdrawals along with
the date each transaction occurred.
3
Measure Performance
Review investment gain, portfolio return,
annualized return, and cash-flow totals.
Net Investment Gain Formula
Net Investment Gain =
Ending Value − Beginning Value − Net External Cash Flows
Modified Dietz Portfolio Return
Portfolio Return =
Net Investment Gain ÷ Weighted Capital Base
Each cash flow is weighted according to the proportion
of the measurement period remaining after that cash flow
occurs.
Cash Flow Weight =
Days Remaining After Cash Flow ÷ Total Days in Period
Portfolio Return Example
Assume you begin with a
$100,000 portfolio and the account
later ends at $118,000.
Beginning Portfolio:
$100,000
Ending Portfolio:
$118,000
Additional Deposit:
$5,000 during the period
Withdrawal:
$2,000 during the period
It would be inaccurate to treat the full increase from
$100,000 to $118,000 as investment performance because
part of the change came from external cash flows. The
calculator adjusts for those flows before estimating
investment return.
Portfolio Growth vs. Portfolio Return
Portfolio Value Growth
Portfolio value growth compares the account's ending
value with its beginning value. Deposits can increase
this figure even when investment performance is weak.
Portfolio Investment Return
Investment return attempts to isolate the gain or loss
generated by the investments themselves after accounting
for external deposits and withdrawals.
This distinction is particularly important when an
investor adds or removes significant amounts of money
during the measurement period.
What Is Annualized Portfolio Return?
Annualized return expresses a portfolio's measured
performance as an equivalent yearly compounded rate.
Annualized Return =
(1 + Period Return)365 ÷ Days − 1
Annualization can make returns measured across different
time periods easier to compare, although short-term
returns should not be interpreted as a prediction of
future annual performance.
Important:
Modified Dietz is an approximation that accounts for
external cash-flow timing without requiring daily
portfolio valuations. Professional performance reporting
may use time-weighted return, internal rate of return,
daily valuation, or other methodologies depending on
the purpose of the calculation.
Portfolio Return Calculator FAQs
Portfolio return measures how much an investment portfolio gained or lost over a period. A useful calculation should distinguish investment performance from money that was added to or withdrawn from the portfolio.
The calculator treats positive cash flows as contributions and negative cash flows as withdrawals. It uses their timing during the measurement period when estimating a Modified Dietz portfolio return.
Modified Dietz is a cash-flow-adjusted return method. It estimates investment performance by weighting each external cash flow according to how long that money was present in the portfolio during the measurement period.
Portfolio value can increase simply because additional money was deposited. Investment return attempts to measure the gain or loss generated by the portfolio itself after adjusting for external cash flows.
Annualized return converts the measured return over a shorter or longer period into an equivalent yearly rate, assuming the same compounded rate continued for a full year.
This calculator provides an estimate for informational purposes. Professional performance reporting may use additional standards, valuation conventions, daily portfolio values, or time-weighted return calculations.