The table lamp should not be taller than 1.5 times the height of the table on which it is placed. The diameter (or the circumference) of the lampshade should not be larger than the diameter of the tabletop. To avoid glare, make sure the bottom of the shade is at eye level while seated. Consider up to 34 inches in the living room (height) and up to 30 inches (height) for bedside tables. The size of the table lamp also depends on the type of room if you're looking for a living room then you can consider some big table lamps also with bright light and if it's for a bedroom then go for a warm light small table lamp. Lamps for study are quite different from normal table lamps as you require adjustable and bit curvy study lamps. Checkout the amazing range of study lamps by Woodenstreet