Censuses are a common data source when analysing migration flows due to their relative completeness and comparability. As opposed to other data sources (e.g. administrative data), which can capture migrations, census data provide information about migrants and five-year information. For simplicity, many studies that have used census data have assumed that the number of migration flows over five years is equal to five times the number of migrants in one year. This is an unrealistic assumption. Notwithstanding that the number of migrations and migrants are very similar when they refer to short intervals (e.g. one year), the number of migrants tend to be fewer than the number of migrations when the time interval is wider (e.g. five years). Thus, there is a need to reduce the impact of having five-year information and to enable comparability between five- and one-year data to estimate bilateral migration flows. This paper proposes a demographic accounting method to translate from five-year migrant data to one-year intervals. This analysis uses data from censuses taken in Argentina, Bolivia, Brazil, Chile, Colombia, Ecuador, Paraguay, Peru, Uruguay, and Venezuela during the 2010s. The results comprise a set of annual bilateral migration flows deduced from five-year information.