What size lamp shade do I need?

Measure your lamp from the bottom of the base to the bottom of the socket, not counting the harp or finial. Choose a shade whose bottom diameter is about that height (within 2 inches either way) and whose vertical height is about two-thirds of it, and make sure the shade is at least ½ inch wider than the base on each side. For an 18-inch base that means a shade about 18 inches across the bottom and 12 inches tall, such as a 11 × 18 × 12.5 empire shade with an 11.5″ harp.

How do I measure a lamp for a lamp shade?

Measure straight up from the bottom of the base to the bottom of the socket (where the bulb screws in). Leave out the harp, bulb and finial. Then measure the widest part of the base; for a square base, measure corner to corner. Those two numbers set the shade’s bottom diameter and height. If you only know the whole lamp’s height including a shade, multiply it by 0.6 to estimate the base-to-socket height.

How do you measure a lamp shade?

Measure four things in inches: the top diameter (straight across the top opening), the bottom diameter (across the bottom), the slant (along the side from top edge to bottom edge) and the vertical height. Lamp shades are listed as top × bottom × slant, so a shade 9 inches across the top, 16 across the bottom and 10 along the side is a 9 × 16 × 10. Its vertical height is 9.4 inches. The calculator’s second tab converts between slant and height.

What do lamp shade dimensions like 9 x 16 x 10 mean?

They are top diameter × bottom diameter × slant: 9 inches across the top, 16 across the bottom and 10 inches along the sloped side. Some sellers list vertical height instead of slant, and a fourth number is the fitter drop. A 9 × 16 × 10 shade stands 9.37 inches tall vertically and suits a lamp base about 14–18 inches tall (base to socket) with an 8.5″ harp.

Are lamp shades sized by the bottom diameter?

Yes. When a store calls something a “16-inch shade” it means the bottom diameter is 16 inches; the top and slant can vary. That is why the bottom diameter is the number to match to your lamp base. Metric shades work the same way: a 40 cm drum is 40 cm across the bottom.

Is there a lamp shade size guide chart?

Yes, the chart on this page lists shade sizes for base heights from 10 to 32 inches. Examples: a 12-inch base takes a 7 × 12 × 8.5 empire shade, a 16-inch base 10 × 16 × 11.5, an 18-inch base 11 × 18 × 12.5, a 20-inch base 12 × 20 × 13.5 and a 24-inch base 14 × 24 × 17. Drum versions keep the top and bottom equal, such as 18 × 18 × 12 for an 18-inch base.

What is the right lamp shade to base proportion?

Three rules from lighting retailers: the shade’s height is about two-thirds of the base height (base to socket); its bottom diameter is about equal to the base height, within 2 inches; and it is at least ½ inch wider than the widest part of the base on each side. Together these make the shade about 40% of the finished lamp’s height, which matches the rule shade makers such as Browns Lampshades give.

What size lamp shade for a 26-inch lamp?

If 26 inches is the whole lamp including the shade, the base-to-socket height is about 15.6 inches, so look for a shade about 16 inches across the bottom (14–18) and 10–11 inches tall, such as 9 × 16 × 10.5. If 26 inches is the base alone (a large lamp), you need a big shade around 26 inches wide and 17 inches tall.

What size shade for a 28, 29½ or 32-inch table lamp?

Using overall lamp heights: a 28-inch lamp takes about a 17-inch shade (10 × 17 × 11.5); a 29½-inch lamp about 18 inches (11 × 18 × 12.5); and a 32-inch lamp about 19 inches (12 × 19 × 13.5). The largest bottom diameter that still looks balanced on a 28-inch lamp is about 19 inches.

What size lamp shade for an 18-inch base?

An 18-inch base (measured to the socket or lamp holder) takes a shade 16 to 20 inches across the bottom and about 12 inches tall: 11 × 18 × 12.5 in an empire shape or 18 × 18 × 12 as a drum, with an 11.5″ harp. A 16-inch base takes about 10 × 16 × 11.5, and a 24-inch base about 14 × 24 × 17.

What size shade for a small 9-inch or 12-inch lamp?

A 12-inch base takes a shade about 12 inches across the bottom and 8 inches tall (7 × 12 × 8.5). A 9-inch base takes about a 5 × 9 × 6.5 shade. Small lamps often use clip-on or uno fitters instead of a harp, so check the fitting before you buy.

What size lampshade do I need for a floor lamp?

Floor lamp shades are sized by the base (foot) diameter. Antique Lamp Supply’s guide: a 10-inch base takes an 18-inch shade, an 11–12-inch base a 19–20-inch shade, and a 13-inch or larger base a 20–22-inch shade, with a shade height of 10–13 inches. A traditional 60-inch floor lamp with an 11-inch base would take about a 12 × 20 × 12.5 shade.

How do I measure for a replacement lamp shade?

If you liked the old shade, measure its top, bottom, slant and vertical height and buy the same size; height matters most. Note the fitter type: spider (sits on a harp and is held by a finial), uno (screws onto the socket) or clip-on (clips to the bulb). If the new shade is taller or shorter, change the harp so the shade still hides the socket.

What size harp do I need for my lamp shade?

Harp size ≈ the shade’s overall height minus its fitter drop, rounded down to the nearest ½ inch (Antique Lamp Supply). Lamps Plus says shades up to 14 inches tall typically have a ½-inch fitter drop. So a 12-inch-tall shade needs about an 11.5″ harp and a 10-inch shade a 9½-inch harp. The size is usually stamped under the harp’s top.

What is the difference between spider, uno and clip-on lamp shade fitters?

A spider fitter is a ring with spokes that sits on top of a harp and is secured with a finial; it is the most common type on table and floor lamps. An uno fitter is a ring that screws onto the socket below the bulb, used on smaller lamps and many European lamps. A clip-on fitter grips the bulb itself and is used on small chandelier and candle-bulb shades.

How wide should a lamp shade be compared to the base?

At least ½ inch wider than the widest part of the base on each side (1 inch wider overall), and usually about as wide as the base is tall. Some retailers use “twice the base width” instead. For a chunky 15-inch-tall base that is 13 inches wide, the calculator recommends about 15–17 inches so the shade doesn’t look perched on top.

Which lamp shade shape should I choose: drum, empire or bell?

Match the shade to the base: round bases suit round shades (drum, empire, bell); square or angular bases suit square shades. Empire shades, which taper from a narrow top to a wide bottom, are the safe default. Drums look modern and throw more light upward; bell shades suit traditional and candlestick bases; coolie shades spread light widely and suit swing-arm and floor lamps.

How tall should a table lamp be next to a sofa or bed?

The bottom of the shade should sit at about seated eye level, 38–42 inches from the floor, so you see light but not the bulb. Lighting New York also suggests table height plus lamp height of 58–64 inches. On a 24-inch nightstand, a lamp with a 14-inch base puts the shade bottom about 38 inches up, which suits reading in bed.

What size lamp and shade for a table 15 inches wide and 22 inches tall?

For seated eye level (38–42″), a 22-inch table needs a lamp about 16–20 inches from base to socket. The shade should not overhang the table, so keep its bottom diameter at 15 inches or less. That points to a slimmer lamp with about a 16-inch base and a 15-inch shade, or a drum shade like 14 × 15 × 10.

How do I convert lamp shade slant to vertical height?

Vertical height = √(slant² − ((bottom − top) ÷ 2)²). For a 9 × 16 × 10 shade: √(10² − 3.5²) = 9.37 inches. A drum’s slant equals its height (8 × 8 × 7½ is 7.5 inches tall), while a steep empire like 6 × 12 × 10 is 9.54 inches tall. Browns Lampshades notes vertical height is usually about an inch less than the slant.

What is the formula for lamp shade surface area and fabric?

Side surface area = π × (R + r) × slant, where R and r are the bottom and top radii. A 9 × 16 × 10 shade has 393 square inches of surface. To cut fabric or contact paper, a tapered shade unrolls to an arc: outer radius = slant × R ÷ (R − r) = 22.9 inches, inner radius 12.9 inches, angle 126°. A drum unrolls to a simple rectangle: circumference × height.

How do I measure a glass shade or shade by circumference?

Divide each circumference by π (3.1416) to get the diameter. A glass shade with an 8-inch circumference at the top and 30 inches at the bottom is about 2.5 inches across the top and 9.5 inches across the bottom. The calculator’s second tab accepts circumferences directly.

Are all lamp shade sizes the same, and how are they measured in cm?

No. There is no single standard; shades come in almost any top, bottom and slant combination, and the bottom diameter is the size people quote. In cm the convention is the same: a 42 cm drum is 42 cm across the bottom. A 42 × 42 × 25 cm drum has a 132 cm circumference and fits a base about 37–47 cm tall to the socket.

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Table lamps · Floor lamps · Shade measurements

Lamp Shade Size Calculator

Quick answer

Measure your lamp from the bottom of the base to the bottom of the socket. The shade’s bottom diameter should be about that height (within 2″), its height about two-thirds of it, and it should be at least ½″ wider than the base on each side. An 18″ base takes a shade about 18″ across and 12″ tall, such as a 11 × 18 × 12.5 empire shade with an 11.5″ harp. Shades are sold as top × bottom × slant.

Enter your lamp’s height to get the shade size, harp size and a fit check for your table, or switch tabs to decode a shade you already own and get its vertical height, circumference, surface area and fabric pattern.

Table and floor lamps, inches or cm
Exact top × bottom × slant size to shop for
Harp size, eye-level and table-width checks
Decode any shade and get a fabric pattern

Last updated October 2, 2026. Sizing rules from Lamps Plus, Antique Lamp Supply, Ballard Designs, Destination Lighting, The Shade Shop and Browns Lampshades. · what size shade · what 9 × 16 × 10 means

Lamp Shade Size Calculator

Find the right shade size for a table or floor lamp, or measure and decode a shade you already have, including its fabric pattern.

Lamp shade size guide chart

Table lamps, by height from the bottom of the base to the bottom of the socket. Sizes are top × bottom × slant in inches.

Base to socket	Finished lamp height	Bottom diameter	Shade height	Empire shade	Drum shade	Harp
10″ (25 cm)	≈ 17″	8–12″	6.7″	6 × 10 × 7.5	10 × 10 × 7	6.5″
12″ (30 cm)	≈ 20″	10–14″	8″	7 × 12 × 8.5	12 × 12 × 8	7.5″
14″ (36 cm)	≈ 23″	12–16″	9.3″	8 × 14 × 9.5	14 × 14 × 9	8.5″
16″ (41 cm)	≈ 27″	14–18″	10.7″	10 × 16 × 11.5	16 × 16 × 11	10.5″
18″ (46 cm)	≈ 30″	16–20″	12″	11 × 18 × 12.5	18 × 18 × 12	11.5″
20″ (51 cm)	≈ 33″	18–22″	13.3″	12 × 20 × 13.5	20 × 20 × 13	12.5″
22″ (56 cm)	≈ 37″	20–24″	14.7″	13 × 22 × 15.5	22 × 22 × 15	14.5″
24″ (61 cm)	≈ 40″	22–26″	16″	14 × 24 × 17	24 × 24 × 16	15.5″
26″ (66 cm)	≈ 43″	24–28″	17.3″	16 × 26 × 17.5	26 × 26 × 17	16.5″
28″ (71 cm)	≈ 47″	26–30″	18.7″	17 × 28 × 20	28 × 28 × 19	18.5″
30″ (76 cm)	≈ 50″	28–32″	20″	18 × 30 × 21	30 × 30 × 20	19.5″
32″ (81 cm)	≈ 53″	30–34″	21.3″	19 × 32 × 22	32 × 32 × 21	20.5″

Bottom diameter = base height ± 2″ (Antique Lamp Supply); shade height = ⅔ of base height (Ballard Designs, Destination Lighting); harp = shade height − ½″ drop, rounded down to ½″. Empire tops are 60% of the bottom; check your base is at least 1″ narrower than the shade.

How to determine lamp shade size

Bottom diameter ≈ base height (± 2″), and ≥ widest part of base + 1″

Shade height ≈ ⅔ × base height (± 1″)

Harp ≈ shade height − ½″, rounded down to the nearest ½″

How to measure a lamp for a shade

Remove the old shade, harp and bulb.
Measure from the bottom of the base to the bottom of the socket (the lamp holder). This is the base height.
Measure the widest part of the base; corner to corner on a square base.
Note the fitting: harp and finial (spider), threaded ring at the socket (uno) or a clip for the bulb.
Optional: measure the table height and top width to check eye level and overhang.

Worked example: 18″ base, 7″ wide

Bottom diameter ≈ base height = 18 in (good range 16 in–20 in)
Widest part of base 7 in + ½″ each side = at least 8 in
Shade height ≈ ⅔ × 18 in = 12 in (±1″)
Empire (classic taper): top ≈ 0.6 × 18 in = 10.8 in
Slant = √(height² + ((bottom − top) ÷ 2)²) = 12.5 in
Harp ≈ shade height − ½″ fitter drop, rounded down to ½″ = 11.5″

Result: shop for about a 11 × 18 × 12.5 shade. The finished lamp is about 30″ tall and the shade is 40% of it, in line with the 40% rule.

Shade size by overall lamp height

If you only know the whole lamp’s height with a shade: the shade is about 40% of it.

Lamp height	Base to socket	Bottom diameter	Shade height
18″	≈ 10.8″	9–13″	7.2″
20″	≈ 12″	10–14″	8″
22″	≈ 13.2″	11–15″	8.8″
24″	≈ 14.4″	12–16″	9.6″
26″	≈ 15.6″	14–18″	10.4″
28″	≈ 16.8″	15–19″	11.2″
30″	≈ 18″	16–20″	12″
32″	≈ 19.2″	17–21″	12.8″
34″	≈ 20.4″	18–22″	13.6″
36″	≈ 21.6″	20–24″	14.4″

Floor lamp shade size chart

Floor lamp shades are sized from the base (foot) diameter, not the pole height.

Base diameter	Shade bottom diameter	Shade height
Up to 10 in	18″	10–13″
11–12 in	19–20″	10–13″
13 in or more	20–22″	10–13″

Source: Antique Lamp Supply. Example: an 11″ base on a 60″ floor lamp takes about a 12 × 20 × 12.5 shade.

Lamp shade measurement chart: what the numbers mean

Shades are listed top × bottom × slant. Here is what common sizes measure vertically and which lamps they fit.

Listed size	Vertical height	Bottom circumference	Fits base (to socket)	Harp
6 × 12 × 9	8.5″	37.7″	10–14″	7.5″
7 × 14 × 10	9.4″	44″	12–16″	8.5″
9 × 16 × 10	9.4″	50.3″	14–18″	8.5″
10 × 18 × 12	11.3″	56.5″	16–20″	10.5″
12 × 20 × 13	12.4″	62.8″	18–22″	11.5″
14 × 14 × 10drum	10″	44″	12–16″	9.5″
16 × 18 × 12	12″	56.5″	16–20″	11″
15 × 17 × 11	11″	53.4″	15–19″	10″

Vertical height = √(slant² − ((bottom − top) ÷ 2)²). A fourth number, if listed, is the fitter drop: how far the spider sits below the top rim.

Lamp shade shapes

Shape	Top ÷ bottom	Best with
Empire (classic taper)	≈ 0.6	Most bases; the safe default
Drum (straight sides)	≈ 1	Modern and cylindrical bases
Tapered drum	≈ 0.85	Transitional lamps
Bell	≈ 0.55	Candlestick and traditional bases
Coolie (wide cone)	≈ 0.3	Swing-arm, floor and accent lamps
Square or rectangle	≈ 1	Square or angular bases

Top-to-bottom ratios are typical catalog proportions, used by the calculator to suggest a top diameter.

Lamp shade fitters

Spider (washer): spokes and a center ring that sit on a harp and are held by a finial. Most table and floor lamps. Change the harp to raise or lower the shade.
Uno: a ring that screws onto the socket below the bulb. Smaller lamps, swing-arm and many European lamps; no harp.
Clip-on: clips onto the bulb. Small chandelier, sconce and candle-bulb shades.
Euro ring (E27 / B22): the metric version of the uno, sized to the socket thread.

How tall should a table lamp be? Placement chart

Aim the shade bottom at seated eye level (38–42″ from the floor). The last column is the overall lamp height for the 58–64″ table-plus-lamp guideline.

Table height	Base to socket for eye level	Overall lamp height (58–64″ rule)
20″	18–22″	38–44″
22″	16–20″	36–42″
24″	14–18″	34–40″
26″	12–16″	32–38″
28″	10–14″	30–36″
30″	8–12″	28–34″

The two rules don’t always agree: the 58–64″ figure assumes a fairly tall side table. When they conflict, keep the shade bottom near eye level so you see light, not the bulb. Keep the shade’s bottom diameter no wider than the table top.

Lamp shade fabric pattern formula

A tapered shade is a cone with its top cut off (a frustum). Flattened, it becomes a curved band:

Outer radius = slant × R ÷ (R − r)
Inner radius = outer radius − slant
Arc angle = 360° × R ÷ outer radius
Surface area = π × (R + r) × slant

For a 9 × 16 × 10 shade: outer radius 22.86″, inner 12.86″, angle 126°, area 393 sq in. Buy a piece about 42″ × 18″.

Common lamp shade sizing mistakes

Measuring to the top of the harp or finial instead of the socket.
Buying by slant when the listing gives vertical height (or the reverse).
A shade narrower than the base, which looks top-heavy and pinched.
The harp saddle or socket showing below the shade: use a longer harp or taller shade.
Ignoring the fitter: uno and clip-on shades won’t sit on a harp.
A shade that overhangs a small nightstand or blocks a wall sconce.

Rules of thumb, not laws

Proportion rules give a starting size; very slim, very wide or sculptural bases may look better a size up or down.
Check the bulb clears the shade: keep at least an inch or two between bulb and fabric, and use LED bulbs in small shades.
Retailers measure differently; confirm whether a listing gives slant or vertical height.

Sources

Antique Lamp Supply — How to determine fabric shade sizeBottom diameter within ±2″ of base-to-socket height; floor lamp shade sizes by base diameter; shade height vs harp
Antique Lamp Supply — How to install, replace and adjust lamp harpsHarp size = overall shade height − fitter recess, rounded down to ½″
Lamps Plus — How to measure a lamp shade and select the right fittingTop, bottom, slant and vertical height; spider, uno and clip-on fitters
Lamps Plus — How to buy a lamp shadeShades up to 14″ high typically have a ½″ fitter drop
Ballard Designs — How do I choose the right lamp shade?Shade about two-thirds of base height; at least ½″ wider than the base on each side; match shade shape to base
Destination Lighting — The comprehensive guide to lamp shadesHeight = ⅔ of base; sizes written top × bottom × slant, optional fourth number for drop
The Shade Shop — FAQShades are named by bottom diameter; the harp saddle should never show
Browns Lampshades — Sizing your lampshadeShade is about 40% of total lamp height; vertical height about 1″ less than slant
Lighting New York — How to choose and style table lampsShade bottom at seated eye level; table + lamp height of 58–64″
Wolfram MathWorld — Conical frustumSlant height and lateral surface area formulas used for shade measurements

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