The quick answer
CSR is how a company describes its commitment to behaving responsibly — often through voluntary initiatives and values.
ESG is how investors and regulators measure that behaviour, through environmental, social and governance factors that are financially material and, increasingly, disclosed under rules. 1
Put simply: CSR is the intent; ESG is the measurement and accountability.
For the full ESG definition, see what is ESG.
What CSR is
Corporate social responsibility describes a company's self-directed efforts to operate ethically and contribute positively to society — community programmes, charitable giving, employee wellbeing and responsible sourcing.
It draws on long traditions of responsible business and aligns with broader commitments such as the UN Global Compact's Ten Principles 3.
CSR is typically narrative, voluntary and reputation-oriented — the domain of purpose statements and community reports rather than investor-grade disclosure.
What ESG is
ESG emerged from the investment community.
The term was coined in the 2004 "Who Cares Wins" report 1 to capture environmental, social and governance issues that are financially relevant, and the Principles for Responsible Investment 2 mainstreamed it from 2006.
ESG is therefore data-driven and decision-useful: it feeds ratings, investment decisions and, in the UK, mandatory disclosure under frameworks including the UK Sustainability Reporting Standards 4.
The key differences
How they overlap
The two are complementary, not opposed.
A company's CSR commitments often supply the activities that ESG then measures and reports — for example, a community or diversity programme (CSR) becomes social-pillar metrics and disclosures (ESG). 2
The pillars that ESG measures are set out in the ESG pillars guide.
Which matters for UK reporting
The UK SRS S1 and S2 4, published on 25 February 2026, formalise ESG disclosure requirements for UK companies.
If your goal is compliance, ESG is the relevant frame — see ESG reporting requirements UK.
CSR programmes remain valuable, but they do not substitute for the measurable, investor-grade reporting that UK SRS and the FCA's sustainability disclosure rules require. 4
Frequently asked questions
What is the difference between ESG and CSR?
CSR (corporate social responsibility) is a company’s broadly voluntary, values-led approach to being a good corporate citizen. ESG is the investor-focused, measurable evolution of that idea: a set of environmental, social and governance factors used to assess financially material risks and opportunities, and increasingly the basis for mandatory disclosure.
Is ESG replacing CSR?
Not exactly — they coexist. CSR still describes a company’s purpose and community initiatives, while ESG provides the metrics, ratings and disclosures that investors and regulators rely on. In practice, ESG has become the dominant language of corporate reporting.
Which one is mandatory?
CSR is generally voluntary. Many ESG-related disclosures, by contrast, are mandatory in the UK — such as climate-related financial disclosure — and the UK Sustainability Reporting Standards extend this further.
