How to Calculate Blended Rate of Return Across Multiple Investments

The Problem With Tracking Positions Individually

Every brokerage account shows per-position returns. Your tech ETF returned 22.4%. Your bond fund returned 4.1%. Your real estate investment trust returned 9.7%. Those numbers are accurate. They are also nearly useless for understanding what your money actually did.

A portfolio is not a collection of individual races. It is a single pool of capital that compounds together. Reporting each position's return without accounting for how much capital sat in each position is like averaging the speed of a motorcycle and a freight train and calling that your commute time.

The correct measure is the dollar-weighted blended return. It weights each position's performance by its proportional share of your total invested capital. The math is straightforward. The discipline to use it consistently is what separates investors who understand their results from those who merely feel good about them.

The Core Formula

The blended portfolio return formula in plain text:

Blended Return = Sum of (Position Weight x Position Return) for all positions

Where Position Weight = (Capital Invested in Position) / (Total Portfolio Capital)

All weights must sum to 1.0 (or 100%). If they do not, you have an accounting error somewhere.

This is the time-weighted, dollar-weighted single-period blended return. It applies cleanly to any snapshot period: one year, one quarter, one decade, as long as you use consistent start and end values for each position.

Worked Example 1: Three-Asset Portfolio

Consider a portfolio with $500,000 in total invested capital, split across three positions.

Position breakdown:

• US Large Cap Equity Fund: $250,000 invested, returned 18.6% over the period
• Investment Grade Bond Fund: $175,000 invested, returned 3.9% over the period
• International Developed Markets ETF: $75,000 invested, returned 11.2% over the period

Step 1: Calculate each position's weight.

• US Large Cap: 250,000 / 500,000 = 0.500
• Bond Fund: 175,000 / 500,000 = 0.350
• International ETF: 75,000 / 500,000 = 0.150

Step 2: Multiply each weight by its return.

• US Large Cap: 0.500 x 18.6% = 9.30%
• Bond Fund: 0.350 x 3.9% = 1.365%
• International ETF: 0.150 x 11.2% = 1.68%

Step 3: Sum the weighted returns.

Blended Return = 9.30% + 1.365% + 1.68% = 12.345%

A simple average of the three raw returns would be (18.6 + 3.9 + 11.2) / 3 = 11.233%.

That 1.112 percentage point difference looks small. Applied to $500,000 over one year, it represents a $5,560 discrepancy in reported gain. Over 10 years at compound growth, that divergence in assumed rate produces a terminal value error of more than $98,000.

The blended figure is correct. The simple average is not.

Worked Example 2: Six-Asset Portfolio With a Losing Position

Real portfolios include losses. The math handles them identically. Negative returns reduce the blended figure proportionally to their weight.

Portfolio: $820,000 total capital

• S&P 500 Index Fund: $300,000, returned 21.3%
• Small Cap Growth ETF: $120,000, returned 14.7%
• Emerging Markets Fund: $90,000, returned -6.2%
• US Treasury Bond ETF: $150,000, returned 2.1%
• REITs: $100,000, returned 8.4%
• Cash Equivalent / Money Market: $60,000, returned 5.1%

Position weights:

• S&P 500: 300,000 / 820,000 = 0.3659
• Small Cap: 120,000 / 820,000 = 0.1463
• Emerging Markets: 90,000 / 820,000 = 0.1098
• Treasury Bond: 150,000 / 820,000 = 0.1829
• REITs: 100,000 / 820,000 = 0.1220
• Money Market: 60,000 / 820,000 = 0.0732

Weighted returns:

• S&P 500: 0.3659 x 21.3% = 7.793%
• Small Cap: 0.1463 x 14.7% = 2.151%
• Emerging Markets: 0.1098 x -6.2% = -0.681%
• Treasury Bond: 0.1829 x 2.1% = 0.384%
• REITs: 0.1220 x 8.4% = 1.025%
• Money Market: 0.0732 x 5.1% = 0.373%

Blended Return = 7.793 + 2.151 + (-0.681) + 0.384 + 1.025 + 0.373 = 11.045%

A simple average of the six raw returns: (21.3 + 14.7 - 6.2 + 2.1 + 8.4 + 5.1) / 6 = 7.567%

Here the gap runs in the opposite direction. The simple average understates performance by 3.478 percentage points because it ignores that the losing position held only 10.98% of capital while the two strongest positions held 50.22% combined.

Applied to $820,000, that gap represents a $28,519 misstatement of actual gain for a single year.

When the Formula Gets More Complex

Multi-Period Returns

The formula above handles single-period analysis cleanly. When comparing performance across periods of unequal length, you need annualized returns before blending. Convert each position's total return to an annualized figure using:

Annualized Return = (1 + Total Return) raised to the power of (1 / Number of Years) minus 1

Write that out: if a position returned 34.5% over 3 years, its annualized return is (1.345 raised to 1/3) minus 1 = 10.37%.

Blend the annualized figures, not the raw cumulative returns. Blending cumulative returns of different lengths produces nonsense.

Cash Flows Mid-Period

If you added or withdrew capital from a position during the measurement period, simple beginning-to-end math distorts results. The modified Dietz method or full internal rate of return (IRR) calculation handles this case. Most sophisticated portfolio management software runs IRR automatically. If you are calculating manually, either use consistent start-of-period capital figures or flag positions with significant mid-period flows for separate treatment.

Reinvested Dividends

Include reinvested dividends in ending value calculations. A bond fund that returned 3.9% in price appreciation but paid an additional 2.4% in reinvested dividends actually returned 6.3% on a total return basis. Blending price-only returns for income-generating assets systematically understates performance.

Why Benchmark Comparison Requires the Blended Figure

Comparing individual positions to benchmarks is a valid tactical exercise. Comparing the S&P 500 fund to the S&P 500 index tells you whether the fund is doing its job. But comparing your overall portfolio to a benchmark index requires your blended return.

If your blended return from Example 2 was 11.045% and the S&P 500 returned 21.3% in the same period, the relevant question is: did your allocation decisions produce appropriate risk-adjusted returns for the diversification you chose to hold? That question requires the blended number. The individual position figures cannot answer it.

Many investors skip this step. They see their equity positions trailing the index and feel underperformance without accounting for the fact that their bond and cash positions provided meaningful downside protection in a different risk scenario. The blended return forces the full picture.

What a Correct Blended Return Tells You

A blended portfolio return answers four questions that individual position tracking cannot.

First, actual capital efficiency. Did your total pool of money grow at a rate worth the illiquidity, risk, and complexity you accepted?

Second, allocation effectiveness. Which positions contributed most to blended performance? A position with a 30% return but only 2% portfolio weight contributed 0.6% to your total. A position with a 9% return and 40% portfolio weight contributed 3.6%. Capital allocation matters more than headline return.

Third, benchmark validity. Your blended return can be compared to a blended benchmark that matches your target allocation, producing a fair performance assessment.

Fourth, forward projection accuracy. If you assume a 10% annual return for planning purposes, that assumption must be grounded in a realistic blended rate given your actual allocation. Using an equity-only return assumption for a portfolio that is 35% bonds and 10% cash overstates expected growth significantly.

Running This Calculation on CalcMoney

The CalcMoney investment return calculator handles multi-position blended return calculations directly. Enter capital deployed per position, the return for each position, and the time period. The tool calculates individual weights, weighted contributions, and the final blended rate.

It also runs annualization for positions of unequal holding periods, which eliminates the most common manual calculation error.

If you are preparing for a portfolio review, rebalancing decision, or tax-loss harvesting analysis, start with your blended return figure. Every downstream decision improves when it is anchored to what your capital actually returned.

Calculate your blended portfolio return on CalcMoney →

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Results are estimates for informational purposes only. Consult a licensed financial professional before making financial decisions.