Carbon stock assessment is a critical component of climate change mitigation, particularly in coastal areas experiencing rapid land-use change. This study aims to estimate aboveground carbon stocks, potential CO₂ emissions, and the economic value of carbon across various land use and land cover (LULC) types in Sungai Kakap District, Kubu Raya Regency, West Kalimantan, Indonesia. A geospatial stock-difference approach was used by integrating land use/land cover maps with carbon emission factors for each LULC category. Carbon stocks were calculated by multiplying the area of each land use class by its respective carbon density, while potential CO₂ emissions were estimated using the IPCC conversion factor (44/12). The economic value of carbon was determined using a carbon price of USD 5 per ton of CO₂. The study results show that the total aboveground carbon stock reached 3.197.198,96 tons of carbon, with an estimated potential emission of 11.723.062,86 tons of CO₂ and a total carbon economic value of USD 15.985.994,81. Mangrove ecosystems contributed the largest carbon stock (1.141.154,51 tons of C), followed by agricultural land (828.861,07 tons of C) and forest formations (620.751,79 tons of C). Consequently, mangroves also exhibit the highest CO₂ emission potential and carbon economic value among all land use classes. These findings highlight the strategic importance of mangrove and forest conservation while promoting sustainable land management to maintain carbon storage, reduce greenhouse gas emissions, and enhance the economic benefits of ecosystem services. Integrating geospatial analysis with carbon valuation provides a practical framework to support low-carbon development and evidence-based land-use planning in coastal landscapes