An operating window for ITER is defined based on mutually consistent core–SOL–divertor modelling, in which the core turbulent transport is based on the Weiland formulation as incorporated into the multi-mode model. The window consists of five limits, one of which is the edge-based density limit based on divertor detachment. The predicted operating space is ample for ITER to fulfil its mission, reaching a maximum Q ≈ 60 at Palpha ≈ 150 MW (65% of the edge-based density limit, 1.1 times the Greenwald limit), and a maximum Palpha of 220 MW at Q ≈ 15 (90% of the edge-based density limit, 1.45 times the Greenwald limit). This operating window takes into account physics constraints and the technical constraints imposed by the divertor system, i.e. peak power load and attainable pumping speed, but does not include further constraints arising from other technological aspects of the ITER design, such as first wall cooling or shielding, which may further limit operation at high fusion power. The operating window is still compatible with the ITER mission if the magnetic field were reduced by 5% or if the underlying core transport were GLF-like rather than Weiland-like. A moderate reduction in helium exhaust or in pumping speed could be accommodated. Other changes in the operating window resulting from different technical or physical hypotheses are also evaluated.