Float-glass ribbon, float-glass sheet, and method for manufacturing float-glass sheet

A float-glass ribbon having a width of at least 800 mm, and an average sheet thickness of 0.25 mm or less in an intermediate region thereof between a position 400 mm inward in the width direction from one width-direction end thereof, and a position 400 mm inward in the width direction from the other width-direction end thereof, the sheet thickness distribution in the width direction satisfying the expressions T0 ≥ T1 and T0 ≥ T2, where T0 is the sheet thickness at the width-direction center of the intermediate region, T1 is the minimum sheet thickness of a first region at a distance of 0.4×W or less inward in the width direction from one width-direction end of the intermediate region, T2 is the minimum sheet thickness of a second region at a distance of 0.4×W or less inward in the width direction from the other width-direction end of the intermediate region, and W is the width of the intermediate region.