Managing stroke risk in people with atrial fibrillation (AF) is critical. The introduction of the CHA2DS2VASc score has lowered the threshold for consideration of anticoagulation to prevent stroke in AF. This means potentially extra work for clinicians in assessing AF patients, and an extra cost to the NHS from more medication and monitoring. This study aims to quantify the increase in the numbers of people requiring anticoagulation with the newer risk assessment score. Method: The GRASP-AF tool was used to quantify the number of people categorised as high risk, using the CHA2DS2VASc score compared with the standard CHADS2 score. Population: An inner-city population from nine general practices within a single Clinical Commissioning Group (CCG), covering a population of 42,274 patients. Results: A total of 395 patients were found to have AF. In this study, 64% were categorised as high risk using CHADS2 compared with 87% on CHA2DS2VASc. This represents an increase of 35% in the numbers of people classed at high risk of stroke and needing to be considered for anticoagulation. Conclusion: There are significant extra costs to implementing the CHA2DS2VASc score, both in drug costs and extra work for primary care, which need to be managed within the local health system. The greatest benefit will be at an individual level. Some people who would have had a stroke will be spared that experience. Who those individuals are, we will never know.