The invention relates to a method in reeling a paper or board web, in which method the web (W) is reeled around a reeling shaft (21; 24) to a web roll (22; 20) by means of a reeling nip between a reeling cylinder (10) and the forming web roll (22, 20), which reeling takes place in a primary stage in a primary position and in a secondary stage in a secondary position. In the method, the reeling cylinder (10) is transferred substantially in the direction corresponding the principal incoming direction (SlO) of the web coming to the reeling cylinder and the forming web roll (20, 22) is transferred from the primary stage to the secondary stage in a substantially horizontal movement. The invention also relates to a method in which the paper or board web is reeled by means of a large-diameter reeling cylinder (10), the proportion of the diameter of which reeling cylinder (10) to the width of the web being reeled is defined such that for the operational area is chosen an area above the curve defined by equation y=- 0,0009x3 + 0,025x2 - 0,2567x + 1,0903 in which y = diameter of reeling cylinder/width of web being reeled and x = width of web being reeled . Furthermore, the invention relates to a reel-up for reeling a paper or board web into a web roll, which comprises means for transferring the reeling cylinder (10) in a direction (SlO) substantially corresponding the principal incoming direction of the web (W) coming to the reeling cylinder (10) and means for reeling the web roll in the primary position and means for reeling the web roll in the secondary position, which are arranged so that the movement of the forming web roll (22) from the primary position to the secondary position is substantially straight in the horizontal direction. The invention also relates to a reel-up in which the proportion of the diameter of the reeling cylinder (10) to the width of the web being reeled is defined such that the operational area is of equation y=- 0,0009x3 + 0,025x2 - 0,2567x + 1,0903.