The free toolkit requires charities to complete an online survey that measures transparency and accountability in areas such as mission and vision, stakeholder relationships and governance reporting.
Participating charities will also be asked to pledge to take specific actions and share good practice.
Richard Marsh, director of the ImpACT Coalition, said: "The toolkit will act as a mirror in which charities can look at themselves. Where improvement is required, it can act as a catalyst for change."
The kit is available at www.impactcoalition.org.uk.