Performance Measurement
What Is Time-Weighted Return (TWR)?
You deposited $8,000 into your account in April, right before a rough month. Your broker app now shows your account is roughly flat on the year. So were you a bad trader this year, or did you just add cash at an unlucky moment?
Those are two different questions, and a single "return" number can only answer one of them. Time-weighted return (TWR) answers the first: how well did your decisions perform, independent of when you moved cash in and out. It is the standard the professional world uses to judge a manager's skill, and once you understand it, your own performance numbers stop lying to you.
- TWR measures the return of your strategy, not the timing of your cash. It removes the distorting effect of deposits and withdrawals.
- It works by chopping your history into sub-periods at every cash flow, measuring each one, then multiplying them together.
- The math is a geometric chain:
(1 + R1) x (1 + R2) x ... - 1. - A big deposit right before a drawdown can make a winning strategy look flat. TWR corrects for exactly this.
- TWR is the metric behind the GIPS standard that regulated firms use to report performance.
Why your account balance is a bad scorecard
Say you start the year with $10,000 and end it with $18,000. You might call that an $8,000 gain and move on. But if you deposited $8,000 during the year, your positions actually did nothing. You added the money yourself.
This is the core problem. The balance in your account moves for two completely different reasons: your trading decisions, and your cash transfers. A raw dollar figure blends them into one number, and you can no longer tell which part is skill.
For traders this matters more than it does for a buy-and-hold investor, because active accounts see cash move constantly. You top up after a good month. You pull profits to pay a bill. You add margin for a setup you love. Every one of those transfers contaminates a naive return figure. We cover this failure mode in depth in why simple return is misleading, but the short version is this: if your performance number changes when you deposit money, it is not measuring your trading.
TWR exists to strip the cash flows back out.
What time-weighted return actually measures
Time-weighted return measures the compound growth rate of one dollar left in your strategy for the whole period, as if you never added or withdrew anything after that first dollar went in.
The trick is to break the timeline every time cash moves. Each segment between cash flows is a "sub-period." Within a sub-period there are no deposits or withdrawals, so the return over that stretch is purely the result of your positions. You measure each sub-period on its own, then link them together by compounding.
Because each sub-period is measured before the next cash flow disturbs it, the size and timing of your transfers never touch the result. A $50 deposit and a $50,000 deposit both just start a fresh sub-period. Neither one flatters or penalizes the return.
The CFA Institute's Global Investment Performance Standards (GIPS) require time-weighted returns for exactly this reason. As the CFA Institute explains, a time-weighted rate of return "removes the effects of cash flows, which are generally client-driven," so it "best reflects the firm's ability to manage the assets" (CFA Institute, Overview of the GIPS Standards). Swap "firm" for "you" and the logic is identical.
How to calculate TWR by hand
The procedure has three steps. You can run the whole thing on paper.
Step 1: Break the period at every cash flow. Every deposit or withdrawal ends the current sub-period and starts a new one. If you had three cash flows during the year, you have four sub-periods.
Step 2: Compute each sub-period's return. For a sub-period with no cash flow inside it, the return is simply:
R = (Ending value - Beginning value) / Beginning value
When a cash flow lands at the boundary, you value the portfolio right before the flow to close the sub-period, then the next sub-period begins with the post-flow value. The point is that the deposit itself is never counted as a gain.
Step 3: Chain the sub-period returns together. Add 1 to each return, multiply them all, and subtract 1:
TWR = [(1 + R1) x (1 + R2) x ... x (1 + Rn)] - 1
That geometric linking is what "time-weighted" means. This is the exact formula documented on Wikipedia's time-weighted return entry, where the growth factor of each sub-period is the ratio of ending to beginning value and the sub-periods are compounded together.
A worked example
Start with the account we opened with.
- January 1: You start with $10,000.
- March 31: Your positions have grown the account to $12,000. Sub-period 1 return is
(12,000 - 10,000) / 10,000 = +20%. - March 31: You deposit $8,000. The account now holds $20,000 to begin sub-period 2. The deposit is a cash flow, not a gain, so it does not appear in any return figure.
- December 31: The account has fallen to $18,000. Sub-period 2 return is
(18,000 - 20,000) / 20,000 = -10%.
Chain them:
TWR = (1 + 0.20) x (1 - 0.10) - 1 = 1.20 x 0.90 - 1 = 0.08 = +8%
Your time-weighted return is +8%. Your trading was genuinely positive for the year.
Now look at what the naive view says. You put in $10,000, then $8,000, for $18,000 of your own money. You ended with $18,000. By that math, your account returned 0%. The naive figure is dead flat, and it is wrong about your skill, because your $8,000 deposit happened to land right before a 10% drawdown. The deposit dragged the dollar-weighted picture down even though every decision you made was, on average, a winner.
That gap between +8% and 0% is the entire reason TWR exists.
When each sub-period has a cash flow inside it
The example above kept things tidy by placing the deposit exactly at a sub-period boundary. In real trading, cash lands mid-period. The standard adjustment neutralizes it in the denominator.
For a sub-period that contains a cash flow, the growth factor is calculated so the flow is added to the beginning value rather than treated as return:
1 + R = Ending value / (Beginning value + Cash flow)
By adding the deposit into the base you are dividing by, its influence on the percentage is cancelled out (AnalystPrep, Money-Weighted and Time-Weighted Rates of Return). Withdrawals work the same way with a negative sign. In practice, most tools value the account at the close of every day, which effectively creates a fresh sub-period boundary daily, so the cash flow almost always sits on a boundary and the simpler formula applies.
TWR is not the whole story
TWR is the right tool for one job: judging the quality of your decisions. It deliberately ignores something a money-weighted return captures, which is whether you had a lot of money working during your best stretches and little money working during your worst.
In our example, TWR says +8%, but the trader actually felt closer to flat, because the big $8,000 was exposed only to the losing sub-period. A money-weighted return, which weights each period by the dollars invested in it, would land below +8% and reflect that lived experience. Neither number is "correct." They answer different questions. TWR asks whether the strategy is good. Money-weighted return asks whether your specific dollars did well given your timing.
For a full side-by-side of the two, including when to trust each, see time-weighted vs. money-weighted return. And because raw return of any flavor ignores how much risk you took to earn it, pair TWR with a risk-adjusted measure before you judge a strategy as good or bad.
Where TWR fits in a trader's review
You do not need to reach for TWR every day. Where it earns its keep is the periodic performance review, when you are trying to answer "is my edge real?" without your deposit and withdrawal noise muddying the picture.
TWR is also the only fair way to compare yourself against a benchmark. An index like the S&P 500 has no external cash flows, so its return is inherently time-weighted. If you want an apples-to-apples "did I beat the market" comparison, your side of the comparison has to be time-weighted too. Comparing a cash-flow-contaminated account return against a clean index return is comparing two different things.
Computing TWR by hand across a year of daily cash flows is tedious, which is why it is worth having a tool do it. Most portfolio trackers, TradeReveal included, will compute a time-weighted return from your positions and cash automatically so the number reflects your trading rather than the timing of your transfers. The point here is the concept, though. Whether you calculate it in a spreadsheet or read it off a chart, TWR is the number to trust when the question is about your skill.
Frequently Asked Questions
What is the difference between time-weighted and money-weighted return?
Time-weighted return measures the performance of the strategy itself by removing the effect of deposits and withdrawals, so cash-flow timing does not change the result. Money-weighted return is the internal rate of return on the actual dollars you invested, so it does reflect timing. Use TWR to judge decision quality and money-weighted return to judge what your specific dollars earned.
Why do professional standards require time-weighted return?
Because deposits and withdrawals are usually driven by the client, not the manager. Removing them isolates the part of performance the manager actually controls. The CFA Institute's GIPS standards require time-weighted returns so that reported performance reflects investment skill and is comparable across firms.
Does a deposit increase my time-weighted return?
No. A deposit starts a new sub-period and is added to the base of the calculation rather than counted as a gain. That is the whole design: the size and timing of cash flows do not move the TWR figure up or down. Only the performance of your positions does.
Is time-weighted return the same as CAGR?
They are closely related. When there are no external cash flows, time-weighted return over a period equals the compound growth of the account, and annualizing it gives you a compound annual growth rate. The difference only appears once deposits and withdrawals enter the picture, where TWR strips them out and a naive CAGR on the raw balance would not.
How often should I calculate TWR?
For most active traders, once per performance review is enough, monthly or quarterly. Any tool that tracks daily account values can compute it continuously, but you do not need to watch it in real time. Its value is in the review, when you want a clean read on whether your edge is working.
Final Thoughts
The reason your account balance keeps lying to you is that it answers a question you did not ask. It tells you how much money is in the account, which depends on both your trading and your transfers. Time-weighted return separates those two forces and hands you the one you actually care about: the return of your decisions.
Once you see the +8% and the 0% side by side in the same year, the value is obvious. Before you judge a strategy, a system, or your own edge, run the number that ignores your cash flows. Then, and only then, ask whether the return was worth the risk you took to earn it.
Start your free TradeReveal account today
Happy Trading,
The TradeReveal Team