Money Weighted Return Calculator

Find the internal rate of return on a portfolio, which does reflect the timing of your cash flows.

About Money Weighted Return Calculator

The Modified Dietz approximation assumes cash flows arrive evenly through the period, so it weights them at half. It is close to a full internal rate of return for typical patterns and far easier to compute. Money-weighted return is what you actually earned, which is why it can differ sharply from the fund’s published time-weighted figure.

Formula

Money Weighted Return

Approximate MWR = gain ÷ (starting value + half of net cash flow)

average capital: Starting value plus half the net contributions, the standard mid-period approximation
gain: Ending value less starting value and net cash added

Worked example

With the default values below, Money Weighted Return Calculator returns Money-Weighted Return of 12.844%. Change any input above and every figure here is recalculated in your browser.

Inputs used

Starting portfolio valueminimum 0: 50,000
Contributions during the periodminimum 0: 12,000
Withdrawals during the periodminimum 0: 3,000
Ending portfolio valueminimum 0: 66,000
Length of the periodaccepts 0.25–40 years: 1 years

Results

Money-Weighted Return: 12.844%
Annualised Money-Weighted Return: 12.844%
Investment Gain: $7,000.00
Average Capital at Work: $54,500.00
Net Cash Added: $9,000.00

Step by step

1Values used
2Money Weighted Return
3Money-Weighted Return= 12.844
4Annualised Money-Weighted Return= 12.844
5Investment Gain= 7,000.00
6Average Capital at Work= 54,500.00
7Net Cash Added= 9,000.00

Assumptions and limits

The result is derived only from the 5 inputs listed above. Anything not among them is not part of the calculation.
In particular, this calculator does not take inflation, tax or fees or charges into account.
Figures are rounded for display to 3 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.
This is an estimate for general information and not professional financial, tax or legal advice. See the full disclaimer for the limits that apply to this kind of calculator.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

Frequently Asked Questions

How is Money Weighted Return calculated?

Approximate MWR = gain ÷ (starting value + half of net cash flow) The Modified Dietz approximation assumes cash flows arrive evenly through the period, so it weights them at half. It is close to a full internal rate of return for typical patterns and far easier to compute.

Why does Money Weighted Return matter?

Money-weighted return is what you actually earned, which is why it can differ sharply from the fund’s published time-weighted figure.

What values do I need to enter?

This calculator takes 5 inputs: Starting portfolio value, Contributions during the period, Withdrawals during the period, Ending portfolio value, Length of the period. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.