A window covering cutting device is disclosed that has a support table, a slot, and a blade. The support table has a support surface on which at least a portion of a window covering can be placed. The clamp has a slot and is positioned near the support surface so there is a plane that passes through the slot. The clamp is moveable from a first open position to at least one clamping position. The blade is positioned for movement from a first position to a second position so that a portion of the blade will be within the slot of the clamp when the blade is in the second position and the clamp is in one of its clamping positions.