Application: Understanding baseline farm greenhouse gas emissions and how they may be mitigated requires a validated, standardised carbon accounting tool. This work demonstrates the extent to which efficiency measures can reduce emissions, and the degree of afforestation needed to enhance sequestration to off-set remaining emissions, enabling farms to reach net zero. Introduction: The Climate Change Committee has recommended a 64% reduction in greenhouse gas emissions from the agriculture and land-use sector to meet the 2050 net zero target in the UK. However, it is still unclear what these changes will look like at a farm level. The aims of this study are: i) to assess the effects of carbon calculator choice on baseline carbon footprints of Welsh beef and sheep farms, and ii) to investigate strategies for these farms to reduce emissions and increase sequestration to achieve net zero. The study will define net zero typologies and assess their effect on production. Material and methods: Carbon footprints were calculated for 20 Welsh beef and sheep farms using three carbon accounting tools: Bangor University’s Carbon Footprinting Tool, AgRE Calc, and the Farm Carbon Calculator. Tools were compared based on their input requirements, emission estimates and sensitivity to mitigation options. A hybrid model including emission estimates from AgRE Calc and sequestration calculations from the Bangor Tool were then chosen to calculate baseline emissions. Mitigation scenarios for each farm were created. Mitigation measures and abatement potentials were sourced from the most recent Marginal Abatement Cost Curve. The reduction in emissions achieved and area of woodland needed for offsetting to reach net zero were noted and the effect on production assessed. Results: Carbon accounting tools have notable differences in emissions estimates (Figure 1) and therefore footprints from different tools are not directly comparable. The application of mitigation measures was projected to reduce emissions by an average of around 30% across all farms. After implementing these measures, the area of farm needed for woodland to off-set (via sequestration) remaining emissions ranged from 15-50%. Therefore, at present, achieving net zero would have a significant effect on production through the reduction in livestock numbers required to ‘free’ land for offsetting purposes. Conclusion: Urgent action must be taken to improve livestock farming's contribution to the net zero target due to its critical role in Welsh society and economy. Calculating carbon footprints of farms is a key first step, but a standardised carbon accounting tool is required to understand both baseline farm emissions and the impacts of mitigation measures. However, mitigation measures alone will not sufficiently reduce emissions, therefore enhancing sequestration through afforestation will be needed. The subsequent impacts of this on production capacity will need to be considered.