Calculate Your Change
Enter an opening and closing value. Add up to three deposits or withdrawals. Cash-flow dates determine their time weights.
Example Data Table
This example shows a common pattern. The calculation separates cash movement from investment movement.
| Start date | Opening value | Cash flow | Flow date | End date | Closing value |
|---|---|---|---|---|---|
| January 1 | $100,000 | Deposit: $10,000 | April 1 | September 30 | $118,000 |
| January 1 | $100,000 | Withdrawal: $5,000 | July 15 | September 30 | $109,000 |
Formula Used
Return (%) = [(EV - BV - Sum(CF)) / (BV + Sum(CF x w))] x 100
- EV is the ending portfolio value.
- BV is the beginning portfolio value.
- CF is a signed external cash flow. Deposits are positive. Withdrawals are negative.
- w is the remaining-period weight:
w = days from cash flow to end date / total period days.
This is the Modified Dietz method. It time-weights flows when values are not available before every cash movement.
How to Use This Calculator
- Choose the first and last dates of the measurement period.
- Enter the opening value from the start date.
- Enter the closing value from the end date.
- Add each deposit or withdrawal with its actual date.
- Select the correct cash-flow type for each entry.
- Choose Calculate Change to view the result above the form.
- Use the export buttons to save the same result as CSV or PDF.
Understand Time-Weighted Year-to-Date Change
Why Cash-Flow Timing Matters
Year-to-date portfolio change should separate market movement from money you added or removed. A simple ending-minus-starting comparison mixes those effects. It may overstate gains after a late deposit. It may understate performance after an early withdrawal. Time weighting fixes this issue. It gives each cash flow a weight based on its position within the selected period. Earlier money affects more days. Later money affects fewer days. This makes the return measure fairer for regular investing, rebalancing, and planned spending.
How the Calculation Reads
The calculation uses a Modified Dietz approach. It starts with the opening value. It adjusts the ending value for signed external flows. Deposits are positive. Withdrawals are negative. It then divides the investment gain by capital available after timing adjustments. The result shows percentage change for the selected dates. It does not treat deposits as investment profit. It does not treat withdrawals as an investment loss. This distinction matters when comparing accounts with different contribution patterns.
Choosing Reliable Inputs
Use portfolio values from the same account scope. Include cash only when it belongs to the investment account. Enter the opening value before any selected-period activity. Enter the closing value at the end date. Add each external deposit or withdrawal separately. Use the actual processing date when possible. A reasonable estimate is better than ignoring a major flow. Keep currencies consistent. Do not combine different currencies without converting them first. Check that each withdrawal has the correct direction before calculating.
Using the Measure in Practice
Review the result beside your benchmark. A positive account change does not always beat the benchmark. A negative result can still be better than a larger market decline. Use the percentage for comparing periods of different sizes. Use the adjusted dollar gain for understanding the money impact. Keep notes about unusual events. Fees, taxes, transfers, and cash sweeps can affect interpretation. Separate performance analysis from planning decisions. A strong return does not guarantee that future returns will match it.
Know the Limits
True time-weighted return normally requires a valuation before every cash flow. This calculator is a practical approximation when those valuations are missing. It is useful for personal portfolios and periodic reporting. It is less precise during volatile periods with large flows. Record values near large deposits or withdrawals when possible. Then compare results across months using the same method. Use a professional report when you need audited performance figures, manager comparisons, or compliance reporting.
Build Better Review Habits
Run the calculation after each month end. Save the inputs with the result. Review cash flows before drawing conclusions. Compare the percentage with your target allocation and risk level. Look for patterns across several periods. Avoid reacting to one short period alone. Consistent records make the measure more useful. They also help you explain results to a planner, adviser, or future self. Good review habits support calmer decisions during changing markets. Use the calculator as one clear checkpoint, then pair it with goals, fees, risks, and practical cash needs before making changes.
Frequently Asked Questions
What does time-weighted YTD change measure?
It estimates portfolio performance from the selected start date through the selected end date. It reduces distortion from external deposits and withdrawals by weighting each flow according to timing.
Is this a true time-weighted return?
It uses the Modified Dietz approach. This is a practical time-weighted estimate. A fully linked return requires portfolio values immediately before every external cash flow.
How are deposits handled?
Deposits are positive cash flows. An earlier deposit receives a larger weight because it was available to participate in investment performance for more days.
How are withdrawals handled?
Withdrawals are negative cash flows. The calculation adjusts for money removed from the account, so a withdrawal does not automatically appear as an investment loss.
Why do I need cash-flow dates?
The date determines the remaining-period weight. Accurate dates improve the estimate, especially when deposits or withdrawals are large relative to the opening value.
Can I enter a flow on the end date?
Yes. A flow on the end date receives a zero remaining-period weight. It still adjusts the ending value and net cash-flow total.
What happens when adjusted capital is zero or negative?
The calculator cannot calculate a meaningful percentage. Review the opening value and withdrawals, then use a shorter period or better valuation data.
Should dividends be entered as cash flows?
Usually no, when dividends stay inside the same investment account. Enter only external deposits and withdrawals that move money into or out of the measured portfolio.
Can I use a fiscal-year start date?
Yes. Change the start date to the beginning of your fiscal year. The same weighting method applies to any valid measurement period.
Does the result show an annualized return?
No. It shows the return for the selected period only. Annualizing a partial-year result can be misleading, especially in volatile markets.
What helps keep results consistent?
Use consistent records for clearer investment performance decisions today.