The Sustainable Development Goals map out a broad spectrum of objectives. Analytical tools in form of the Index and Dashboards provide a starting point to set national baselines, and allow comparison of the SDGs with other indices of well-being. The Sustainable Development Goals (SDGs) — agreed in 2015 by all 193 member states of the United Nations and complemented by commitments made in the Paris Agreement — map out a broad spectrum of economic, social and environmental objectives to be achieved by 2030. Reaching these goals will require deep transformations in every country, as well as major efforts in monitoring and measuring progress. Here we introduce the SDG Index and Dashboards as analytical tools for assessing countries' baselines for the SDGs that can be applied by researchers in the cross-disciplinary analyses required for implementation. The Index and Dashboards synthesize available country-level data for all 17 goals, and for each country estimate the size of the gap towards achieving the SDGs. They will be updated annually. All 149 countries for which sufficient data is available face significant challenges in achieving the goals, and many countries' development strategies are imbalanced across the economic, social and environmental priorities. We illustrate the analytical value of the index by examining its relationship with other widely used development indices and by showing how it accounts for cross-national differences in subjective well-being. Given significant data gaps, scope and coverage of the Index and Dashboards are limited, but we suggest that these analyses represent a starting point for a comprehensive assessment of national SDG baselines and can help policymakers determine priorities for early action and monitor progress. The tools also identify data gaps that must be closed for SDG monitoring.