The UNEP OzonAction GWP-ODP Calculator app will help you to convert between values in metric tonnes, ODP tonnes and CO2-equivalent tonnes (or kg) of substances controlled by the Montreal Protocol and their alternatives. The updated application now includes a new Kigali Amendment mode. The app can now be used in two different modes: the regular "Actual Values" mode and the "Kigali Amendment" mode. In the Kigali Amendment mode, the global warming potential (GWP) values provided are those specified in the Kigali Amendment to the Montreal Protocol, i.e. GWP values are only assigned to controlled HFCs. In this mode the GWP values used to calculate the refrigerant blends/mixtures only include GWP contributions from components that are controlled HFCs. The user can effortlessly switch between modes. The OzonAction GWP-ODP Calculator uses standard ODP values and GWP values as specified in the text of the Montreal Protocol to make the conversions; other ozone depleting potential and global warming potential values from the recent reports from the Montreal Protocol technology and scientific expert panels as well as the Intergovernmental Panel on Climate Change (IPCC) are used when appropriate, with references to sources of all values used. The app includes new refrigerant mixtures (with ASHRAE approved refrigerant designations). The app can be viewed in English, French or Spanish.

For single component substances simply select a substance from the dropdown list and enter the known value in the appropriate field (e.g. a quantity in Metric tonnes). The calculator will automatically perform the conversion between metric tonnes, ODP tonnes and/or CO2-equivalent tonnes (or kg) and display the corresponding converted values. The ODP, GWP and description of substance are also provided.

For refrigerant mixtures/blends, simply select the name of the blend and enter the quantity. The calculator will display the corresponding total ODP tonnes and CO2- equivalent tonnes for that quantity of substance. The components of the mixture and their relative proportions (metric, ODP, CO2- equivalent) are also displayed. Both these types of calculations can be carried out in both the "Actual Values" mode and the "Kigali Amendment" mode.

This application is designed primarily for use by Montreal Protocol National Ozone Units and other related stakeholders. The application was produced by UN Environment Programme (UNEP) OzonAction as a tool principally for developing countries to assist them in meeting their reporting and other commitments under the Protocol and is part of the OzonAction work programme under the Multilateral Fund for the Implementation of the Montreal Protocol.