Enter each dated contribution (+) or withdrawal (−) between your start and end dates. The value before flow column is optional. Fill it in for every flow and the calculator can also compute a true time-weighted return and show you exactly how far the approximation drifts.
Date
Flow on this date + in / − out
Value before flow optional
Don't enter internal moves. Selling one fund to buy another, or a dividend reinvested inside the account, is not a contribution: no money crossed your account boundary. Modified Dietz only weights money you actually paid in or took out; entering an internal move corrupts both the net flow and the average-capital denominator.
End of day (default): a flow is invested for the days after it, w = (TD − t) ÷ TD. Start of day: it earns the flow day too, w = (TD − t + 1) ÷ TD. The chosen convention is stated and locked into your result.
Check these before calculating
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Modified Dietz: day-weighted return
Your day-weighted Modified Dietz return, with the net flow, the weighted-flow sum and the average-capital denominator laid out so you can check it by hand, will appear here.
Illustrative only. This calculator does arithmetic on the figures you enter. It is not financial advice. Monverdo reports on figures; it does not advise.
Monverdo (Pty) Ltd is a South African company. Nothing on this site is advice as defined in the Financial Advisory and Intermediary Services Act 37 of 2002 (the FAIS Act).
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