The WHO is a specialized agency of the United Nations (defined as "international organization(s) that coordinate their work with the United Nations through negotiated agreements"). As such, the WHO is legally independent of the United Nations and thus has a separate budget, members, rules, and personnel (see source 1).
Funding for the WHO (i.e. revenue) is comprised of four primary sources: assessed contributions, voluntary contributions, contributions in-kind and in-service, and reimbursable procurement, concessions, revolving sales, and other exchange revenue.
Assessed contributions come directly from member states and associate member in the form of membership dues, and they are calculated relative to the member state's wealth and population.
Voluntary contributions are additional contributions outside of the assessed contributions and come from both member states and independent third parties (i.e. the Bill and Melinda Gates Foundation).
Contributions in-kind also come from either member states or other contributors and are, by definition, non-cash contributions. The WHO splits in-kind contributions into three categories: medical supplies and materials, office space and field supplies, and in-service.
Finally, reimbursable procurement pertains to medicines, vaccines, equipment, and other supplies procured by WHO on behalf of member states and other UN agencies (all above information was sourced from the WHO's audited financial statements for CY2018).
At a high level, for CY2016, the revenue breakdown is as follows:
- Member States—51%
- Philanthropic Foundations—17%
- UN intergovernmental organizations and development banks—5%
Partnerships, NGOs, private sector entities, and academic institutions comprise the balance (see source 3 for infographics containing this information).