SROI calculator.
Estimate a project's Social Return on Investment using the method in A Guide to Social Return on Investment, with an explanation for every input.
SROI Calculator
Estimate a project's social return on investment. Enter the investment and expected outcomes to see the SROI ratio instantly.
The values shown are an illustrative example. Replace them with your project's data.
Every 1 baht invested creates about 1.83 baht of social value (present value)
- Present value of outcomes
- 1,825,112 THB
- Investment
- 1,000,000 THB
- Net present value
- 825,112 THB
| Outcome | Year-1 value after adjustments | Present value | Share |
|---|---|---|---|
| Participants earn more | 768,000 | 1,583,303 | 87% |
| Lower healthcare costs | 168,750 | 241,808 | 13% |
Sensitivity: if deadweight and attribution were 10 points higher, the ratio would fall to 1 : 1.40
This is a planning estimate, not an assured SROI report. A full evaluation identifies stakeholders, measures real outcomes and tests sensitivity under Social Value International's Principles of Social Value.
How it's calculated
Value per year = quantity × value per unit × (1 − deadweight) × (1 − attribution) × (1 − displacement). Later years decline by the drop-off rate and are discounted to present value by (1 + discount rate)^year. SROI ratio = total present value ÷ total investment, following A Guide to Social Return on Investment (Cabinet Office / SROI Network, 2012).
What the SROI ratio means
The SROI ratio compares the present value of the social value created with the total investment. A ratio of 1 : 3 means every 1 baht invested creates about 3 baht of social value. Above 1 : 1, the value created exceeds the money spent. Avoid comparing ratios across projects directly: each evaluation rests on its own assumptions and financial proxies.
The four adjustments that make the number credible
- Deadweight What would have happened anyway without the project; use a comparison group or benchmark data.
- Attribution The part caused by others, such as another agency helping the same group; removed to avoid double-counting.
- Displacement The part that only moves a problem or benefit elsewhere; usually 0% unless there is a specific reason.
- Drop-off How much the outcome declines each year after the first; applies when outcomes last more than one year.
How to choose a financial proxy
- Costs actually avoided e.g. healthcare or welfare costs the state no longer pays.
- Increased income e.g. participants' earnings after finding work or growing a business.
- Market price of a substitute e.g. the fee for a course or service with a similar effect.
- Willingness to pay for outcomes with no market price, such as wellbeing. Always cite a source.
When you need a full SROI
This calculator suits forecasts before a project starts. If you report to funders or a board, or include the result in a sustainability report, commission a full evaluation that engages stakeholders, measures real outcomes and tests sensitivity under Social Value International's principles.
Frequently asked questions
- What is the SROI formula?
- The SROI ratio is the present value of outcomes divided by total investment. Each outcome's yearly value is the number of people affected times the value per unit, less deadweight, attribution and displacement. Later years decline by the drop-off rate and are discounted to present value.
- What is a good SROI ratio?
- There is no fixed threshold. Above 1 : 1 means social value exceeds the investment, but the credibility of the assumptions matters more than the number. A very high ratio is a signal to re-check financial proxies and deadweight.
- Which discount rate should I use?
- Use your organization's or funder's rate if there is one. The calculator's 3.5% default follows the HM Treasury Green Book social discount rate. Always state the rate and test sensitivity.
- Can this calculator replace an SROI report?
- No. It gives a planning estimate. An SROI report needs real stakeholder data, checked assumptions and a transparently documented sensitivity analysis.
Read more: What is SROI? Formula and steps →NXT's SROI evaluation service →
References
- Cabinet Office / The SROI Network (2012). A Guide to Social Return on Investment.
- Social Value International. Principles of Social Value.
- HM Treasury. The Green Book: Central Government Guidance on Appraisal and Evaluation.