Question 1

What is a good ROI?

Accepted Answer

It depends on the investment type and time horizon. The S and P 500 averages 10% annual ROI over the long term, real estate 8-12%, REITs 7-10%, rental properties 6-12%, and high-yield bonds 4-6%. Venture capital targets 20-30% but with high risk. Generally, anything beating inflation (2-4%) is a positive real return, and 10%+ annualized is considered strong for most investors.

Question 2

Does ROI account for time?

Accepted Answer

Basic ROI does NOT account for time, which is a major limitation. A 50% ROI over 1 year is vastly different from 50% over 10 years. For time-adjusted returns, use annualized ROI: (Final/Initial)^(1/years) - 1. For complex cash flows with multiple investments and withdrawals, use IRR (Internal Rate of Return) or CAGR (Compound Annual Growth Rate).

Question 3

Can ROI be negative?

Accepted Answer

Yes. Negative ROI means you lost money. If you invested $10,000 and the final value is $8,000, ROI = ($8,000 - $10,000) / $10,000 = -20%. Negative ROI is common for risky investments in the short term. Even the S and P 500 has had years with -10% to -40% returns during market crashes, though long-term averages remain positive.

Question 4

What is the difference between ROI and ROAS?

Accepted Answer

ROI measures total return including all costs and is expressed as a percentage: (Profit / Cost) x 100. ROAS (Return on Ad Spend) only measures revenue generated from advertising divided by ad cost, typically expressed as a ratio: $5 of revenue for every $1 spent = 5:1 ROAS. ROAS ignores product costs, fulfillment, and overhead, making it useful for marketing teams but not for true profitability.

Question 5

How do I calculate ROI for a rental property?

Accepted Answer

For rental properties, use: (Annual Rental Income - Annual Expenses) / Total Investment x 100. Include mortgage interest, property taxes, insurance, maintenance, vacancy allowance (5-10%), and property management fees. A $200,000 rental generating $24,000/year gross, with $14,000 in expenses, produces $10,000 net profit. ROI = $10,000 / $200,000 = 5% cash-on-cash return. Add appreciation for total ROI.

Question 6

What is the difference between ROI and IRR?

Accepted Answer

ROI is a simple percentage of total return, while IRR (Internal Rate of Return) accounts for the time value of money and multiple cash flows. For a single investment with one return, ROI and annualized ROI work fine. For complex scenarios with varying contributions and withdrawals (like a rental property over 10 years), IRR provides a more accurate annualized rate. IRR is the discount rate that makes net present value equal zero.

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投資収益率（ROI）とは何ですか？

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良いROIとは何ですか？

ROIは時間を考慮しますか？

ROIはマイナスになることがありますか？

ROI計算機を自分のサイトに追加するにはどうすればよいですか?

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