High teacher turnover—or churn—undermines student achievement and consumes valuable staff time and resources. It also contributes to teacher shortages throughout the country, as roughly 6 of 10 new teachers hired each year are replacing colleagues who left the classroom before retirement. Research shows that urban districts can, on average, spend more than $20,000 on each new hire, including school and district expenses related to separation, recruitment, hiring, and training. These investments don’t pay their full dividend when teachers leave within 1 or 2 years after being hired. Turnover rates vary by school and district, with those in rural and urban settings or that serve high percentages of student in poverty experiencing the highest rates. Use this tool to estimate the cost of teacher turnover in your school or district and to inform a local conversation about how to attract, support, and retain a high-quality teacher workforce. High-leverage strategies are highlighted below.