TWR vs MWRR: which return metric should you trust?

TWR vs MWRR: which return metric should you trust?

If you have ever compared your portfolio return to a benchmark and felt the numbers did not add up, the problem is often which return metric you are reading. Time-weighted return (TWR) and money-weighted return (MWRR) answer different questions — and confusing them leads to wrong conclusions about your own performance and the funds you invest in.

Here is the practical difference and when each metric matters.

What they measure

Time-weighted return (TWR) measures the performance of the investment strategy itself, removing the effect of when you added or withdrew money. It treats every sub-period equally regardless of how much capital was invested during it. This is why fund managers are required to report TWR: it tells you how good their strategy was, not how much you personally benefited from it.

For a deeper look at the TWR formula, see our guide on time-weighted rate of return .

Money-weighted return (MWRR), also called the internal rate of return (IRR), measures the actual return on your specific cash flows. It is your personal return as an investor — the compound rate that makes the present value of your contributions equal to your ending portfolio value. If you added money at the wrong time, MWRR captures that cost. If you got lucky with timing, MWRR captures that too.

For a full breakdown of the MWRR formula and worked examples, see our money-weighted rate of return guide .

A worked example

Suppose a fund has this return sequence:

TWR calculation: (1 + 0.50) × (1 − 0.30) − 1 = 1.05 − 1 = +5%

The strategy delivered 5% over two years.

Now imagine two investors:

• Investor A put in £10,000 at the start and held for both years. End value: £10,500. MWRR ≈ +5% — matches TWR because timing was identical.
• Investor B put in £1,000 at the start, then added £50,000 after Year 1 (excited by the 50% gain). After Year 2’s −30% drop, the large second deposit was heavily penalised. End value ≈ £37,200 on £51,000 total contributed. MWRR ≈ −27%.

Same fund. Same strategy (TWR +5%). Radically different personal outcomes — because MWRR reflects the timing of Investor B’s capital deployment.

Which metric should you use?

A backtesting tool like Wallible calculates TWR on the simulated portfolio — which is correct for strategy evaluation. When you run a backtest from a start date with a lump-sum initial investment and no intermediate cash flows, TWR and MWRR produce the same result, so the comparison is clean.

Common mistakes

1. Comparing your MWRR to a benchmark’s TWR and concluding the strategy underperformed Your MWRR includes your deposit timing; the benchmark’s TWR does not. A strategy that returned +60% TWR can still produce a negative MWRR for an investor who bought heavily near the peak.

2. Using MWRR to judge a fund manager The manager cannot control when investors add or remove money. TWR is the only fair metric for evaluating strategy quality.

3. Assuming a high TWR means you made money If you joined late or invested unevenly, your MWRR may be far lower than the fund’s advertised TWR. Check both.

4. Ignoring sub-period length TWR compounds sub-period returns. If you are calculating manually, use daily or weekly sub-periods, not annual. Coarser sub-periods introduce error, especially around cash-flow events.

FAQ

What does TWR stand for? TWR stands for time-weighted return (also written TWRR, time-weighted rate of return). It measures investment performance by eliminating the distorting effect of cash flow timing.

Is MWRR the same as IRR? Yes. Money-weighted return and internal rate of return (IRR) are the same concept: the discount rate that sets the net present value of all cash flows to zero. In portfolio reporting, MWRR is the commonly used term.

Which return does a portfolio backtest show? A backtest with a single initial investment and no withdrawals will show TWR. If the backtest allows you to model periodic deposits, it may show MWRR or provide both. Wallible’s backtest results use TWR — the standard for strategy evaluation.

Can TWR and MWRR differ significantly? Yes, dramatically. In volatile markets, an investor who adds capital at the wrong moment can experience an MWRR far below (or above) the strategy’s TWR. The gap grows with volatility and the size of poorly-timed deposits.

Which is higher — TWR or MWRR? Neither is systematically higher. If you added capital before strong periods, MWRR > TWR. If you added capital before weak periods, MWRR < TWR. With no intermediate cash flows, they are equal.

Run your own backtest

See how TWR plays out on real historical portfolios — without needing a spreadsheet.

Try Wallible’s free portfolio backtesting tool