Abstract Presented here are cyclostratigraphic time-series data, using magnetic susceptibility (χ) results from Devonian Moroccan rocks to establish a floating-point age chronology, and a method that can be applied to any geological stage using geochemical or geophysical datasets as a climate proxy. The χ data are fit to an independent uniform climate model for the entire Eifelian Stage. The procedure used comprised: (a) definition of a uniform c. 405 kyr eccentricity climate model for the Eifelian, with a published duration for the Eifelian; and (b) graphical testing of the model using χ data derived from outcrop samples, here including data from the Global Boundary Stratotype Section and Point for the Emsian–Eifelian and Eifelian–Givetian stage boundaries, and an overlapping succession from Bou Tchrafine, Morocco. The time-series methods used here identify χ cycles that conform to the c. 405 kyr by graphically comparing the χ zonation with the climate model. Well-established conodont zonations developed using graphic correlation are then compared with this model, allowing time estimates for Eifelian conodont zone ranges. The time-series data indicate that the Eifelian Stage in the Middle Devonian lasted for c. 6.28 myr, the Lower Eifelian Choteč bio-event lasted for c. 600 kyr, and the Kačák bio-event in the Upper Eifelian lasted for c. 370 kyr.