REDD Abacus SP is a public domain software to estimate emission from land use and land cover changes allowing for dynamic heterogeneity of soil types, elevations, climate and other biophysical characteristics in the landscapes; analyze trade-offs between emissions and financial gain (opportunity cost analysis) and produce abatement cost curves project ex-ante emissions and financial gain of business-as-usual scenarios for setting Reference Emission Level (REL); simulate zone-specific policies and other emission-reduction scenarios within the landscapes and estimate the potential emission reductions and opportunity costs of them.