Lamp Shade Size Calculator

Measure your lamp’s base: its height to the socket and its widest point. You get the shade’s size to buy, as top × bottom × slant, and the harp that holds it.

The lamp
in
in
The shade’s shape

Lamp shade to buy

18″ drum shade18 × 18 × 12″ · a 12″ harp

Your lamp and its shade, to scale
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    Quick answer: measure the lamp’s base from the table to just below the socket, and across its widest point. The shade’s bottom should be about twice the base’s width, or close to the base’s height, and the shade half to two thirds as tall as the base. A 20″ base, 8″ wide, takes an 18″ shade about 12″ tall on a 12″ harp. Shades are sold as Top × Bottom × Slant.

    How to use the lamp shade size calculator

    1. Pick a table or a floor lamp. Floor lamp shades are sized by the width of the lamp’s foot.
    2. Measure the base’s height from the table to just below the socket, where the harp’s saddle sits.
    3. Measure the base’s widest point across the body (for a floor lamp, across its foot).
    4. Pick drum or empire. You get the shade to buy, its harp, and each shop’s rule. Copy link keeps the result.

    The rules behind the numbers

    Bottom width: two rules, met in the middle

    Lamp shops size the shade’s bottom two ways. Sorella Glenn and Newport Lamp & Shade go by width: about twice the base’s widest point. Antique Lamp Supply and Lamps Plus go by height: within 2″ of the base’s height, measured to just below the socket. The two often differ by 2–4″, so the calculator meets them in the middle, in the even sizes shades are sold in. For a tall, slim lamp, it stays within 2″ of twice the width, because a shade sized by height alone looks top-heavy (Sorella Glenn’s buffet-lamp exception).

    Height: half to two thirds of the base

    Sorella Glenn makes the shade about two thirds of the base’s height. Lamps Plus makes it about a third of the whole lamp, which works out to half the base. The calculator takes the whole inch in the middle.

    The harp: the shade’s height, within ½″

    The harp is the wire loop that holds a spider-fitter shade over the bulb. Antique Lamp Supply’s rule: the shade’s height within ½″ of the harp’s, so the shade’s bottom hides the socket. Harps are sold in half inches from 4″ to 15″. Keep the bulb at least 1″ from the shade.

    Top × Bottom × Slant

    Shades are listed as the width across the top, across the bottom, and the height along the side (the slant), and called by their bottom: an 8 × 18 × 13″ empire is an 18″ shade. A drum is as wide on top as on the bottom; an empire tapers to about 40% on top.

    Table lamp shade size chart

    Base (height × widest)Drum shadeEmpire shadeHarp
    14″ × 5″12 × 12 × 8″6 × 12 × 8½″8″
    16″ × 6″14 × 14 × 9″7 × 14 × 9½″9″
    18″ × 7″16 × 16 × 11″7 × 16 × 12″11″
    20″ × 8″18 × 18 × 12″8 × 18 × 13″12″
    24″ × 10″22 × 22 × 14″10 × 22 × 15″14″
    28″ × 10″ (slim)22 × 22 × 15″10 × 22 × 16″15″

    Floor lamp shade size chart

    Width of the footShade bottom (Antique Lamp Supply)Shade height
    10″18″10–13″
    11–12″19–20″10–13″
    13″ and up20–22″10–13″

    Three worked examples

    A 20″ table lamp base, 8″ across. Twice the width says 16″; the height says 18–22″. They meet at 18″. Half to two thirds of the base is 10–13⅓″, so the shade is 12″ tall: an 18 × 18 × 12″ drum on a 12″ harp.

    The same lamp with an empire shade. Same 18″ bottom and 12″ height; the top narrows to 8″, so the slant is 13″: buy an 8 × 18 × 13″ empire on a 12″ harp.

    A tall, slim buffet lamp. A 28″ base, 10″ across: by height the shade would be 26–30″ across, far too heavy for a slim lamp. The calculator keeps to 22″, within 2″ of twice the width, and 15″ tall on a 15″ harp.

    Common lamp shade mistakes

    • Measuring the whole lamp. The base’s height stops just below the socket. The harp and the shade come on top.
    • A shade narrower than the base. It looks like a hat on a bottle. The bottom should be well wider than the base’s widest point.
    • Showing the socket. If you see the harp’s bottom or the socket under the shade, the harp is too short or the shade too short.
    • Mixing up the fitter. A spider shade needs a harp; an uno shade screws onto the socket; a clip-on sits on the bulb. Check yours before you buy.
    • A bulb too close to the fabric. Keep the bulb 1″ or more from the shade, especially in a narrow-topped empire.

    Planning the room around the lamp? Lay it out to scale in the free 2D room planner, and size the nightstand with the nightstand and headboard calculator.

    Plan the room free

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    Lamp shade size questions

    How do you size a lampshade?

    Measure the base from the table to just below the socket, and across its widest point. Choose a shade whose bottom is about twice the base’s width or close to its height, and whose height is half to two thirds of the base’s.

    How do you measure a lampshade?

    Measure across the top, across the bottom, and along the side from the top edge to the bottom edge (the slant). Shades are listed in that order, Top × Bottom × Slant, and called by the bottom: 8 × 18 × 13″ is an 18″ shade.

    How do you measure a lamp for a lampshade?

    Measure the base’s height from the table to just below the socket, and its widest point across the body. For a floor lamp, measure across its foot.

    What size harp do I need for my lamp shade?

    A harp about as tall as the shade, within ½″, so the shade’s bottom edge hides the socket. Harps are sold in half inches from 4″ to 15″; an 18″ drum 12″ tall takes a 12″ harp.

    What size lampshade for a floor lamp?

    Antique Lamp Supply sizes it by the foot: a 10″ foot takes an 18″ shade, 11–12″ a 19–20″, and 13″ or wider a 20–22″, each 10–13″ tall.

    Should a lampshade be wider than the base?

    Yes: about twice as wide as the base’s widest point. A shade barely wider than the base looks too small and throws light only up and down.

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