Patio Umbrella Size Calculator

How big a canopy does a table need?

The usual rule is the one California Umbrella gives in its table-setting guide: the canopy "should extend at least 2 feet beyond the table edge on all sides." That is a rule of thumb from the sellers, not a standard, but it is easy to check: the canopy's width is the table's width plus 4 feet (1.2 m). That margin is what keeps the chairs, not just the table, in the shade.

The same guide pairs a 9 ft umbrella with a 4-person table of 36 to 48 inches (0.9 to 1.2 m) and an 11 ft one with a 6-person table of 60 to 72 inches (1.5 to 1.8 m). The calculator's rule agrees for the 4-seat table and lands a size lower for the biggest 6-seat table: a 6 ft (1.8 m) round table needs 10 ft (3 m) of canopy by the rule, and 10 ft canopies are made (Shademaker's Omega is one), but not every maker sells one, so a 6-seat table is often shaded with an 11 ft umbrella. Where the rule gives a size no one sells, the calculator rounds up to the next size sold.

Round table	Canopy by the 2 ft rule	Size to buy	Shade straight above
3 ft (0.9 m)	7 ft (2.1 m)	7.5 ft (2.3 m)	44 sq ft (4.1 m²)
4 ft (1.2 m)	8 ft (2.4 m)	9 ft (2.7 m)	64 sq ft (5.9 m²)
5 ft (1.5 m)	9 ft (2.7 m)	9 ft (2.7 m)	64 sq ft (5.9 m²)
6 ft (1.8 m)	10 ft (3.0 m)	10 ft (3.0 m)	79 sq ft (7.3 m²)
7 ft (2.1 m)	11 ft (3.4 m)	11 ft (3.4 m)	95 sq ft (8.8 m²)

The shade areas match what California Umbrella's FAQ gives: about 45 sq ft for a 7.5 ft umbrella, 63 for a 9 ft one and 95 for an 11 ft one. It also says the 9 ft is "ideal for shading a 6-person dining set" and the 11 ft "perfect for shading a 6-8 person dining set." The size on the label is the open canopy's diameter, not the height of the umbrella, which is the same FAQ's answer to the commonest mistake.

Round, square or rectangular?

A round canopy over a round or square table is the simplest fit. Over a long rectangular table it is wide where the table is narrow: a 6 x 3 ft (1.8 x 0.9 m) table needs 10 ft of round canopy to clear its ends, which leaves 3.5 ft (1.1 m) hanging past the sides. A rectangular canopy matched to the table, 10 x 7 ft (3 x 2.1 m) by the rule, wastes less and shades the whole length, and an 8 x 10 ft (2.4 x 3 m) one covers that table. Rectangular canopies come in far fewer sizes than round ones. Treasure Garden lists an 8 x 10 ft, and it and Shademaker a 10 x 13 ft, so a bigger table may need two umbrellas or a different kind of cover: see shade sail vs awning vs pergola.

The calculator rounds up to sizes that California Umbrella, Treasure Garden or Shademaker list: round canopies of 6, 7.5, 9, 10, 11 and 13 ft, square ones of 6.5, 8, 9, 10, 11.5 and 13 ft. It stops at 13 ft. Shademaker's commercial Astral goes to 16.5 ft, but a canopy that size is a job for the maker, who has to size the base too.

How heavy a base?

A base's job is to stop the umbrella tipping, so its weight has to rise with the canopy, and a cantilever, whose canopy hangs to one side, needs far more than a centre pole. Makers print the figure on the product. These are Shademaker's minimum base weights for a free-standing umbrella, from each model's page:

Type	Model	Canopy sizes	Minimum base
Centre pole	Libra	6.5 to 8 ft (2 to 2.5 m) / 9 ft (2.7 m)	100 lb (45 kg) / 120 lb (54 kg)
Centre pole	Aquarius	7.5 to 9 ft (2.3 to 2.7 m)	100 lb (45 kg)
Centre pole	Omega	10 to 11.5 ft (3 to 3.5 m)	150 lb (68 kg)
Centre pole	Atlas	10 to 11.5 ft / 13 ft (4 m)	300 lb (136 kg) / 400 lb (181 kg)
Centre pole	Astral	13 ft / 16.5 ft (5 m)	500 lb (227 kg) / 600 to 700 lb (272 to 318 kg)
Cantilever	Solaris	9 ft / 10 ft / 11 ft	300 lb (136 kg) / 300 to 350 lb (136 to 159 kg) / 400 lb (181 kg)
Cantilever	Taurus	10 ft (3 m)	300 lb (136 kg)
Cantilever	Polaris	10 x 13 ft and 11.5 ft / 13 ft	550 lb (249 kg) / 700 lb (318 kg)

Two things to know about those figures. They are one commercial maker's minimums, which are higher than the 50 lb (23 kg) and 75 lb (34 kg) bases California Umbrella sells for its residential umbrellas, so read your own umbrella's manual and use the heavier number if they differ. And when a size has two figures, the calculator shows the whole range and picks an end: the lower for a sheltered spot, the higher otherwise. That choice is ours, not Shademaker's. Shademaker also says that "sufficient base weight must be used to secure umbrellas at all times" and that a mount kit, fixed to the ground, is "always the preferred method."

Through a table, the table's own weight helps, and the calculator says so but still shows the free-standing figure, because no maker publishes a through-table number. California Umbrella says an umbrella in a table "should also be used in conjunction with a base of a suitable weight." Treasure Garden's 35 lb steel base is "best used for under-the-table applications (not recommended for free-standing applications)", and its 70 lb steel base is for dining tables too. Cantilevers use sand-filled bases to get their weight home: Treasure Garden's AKZ base weighs 38 lb (17 kg) empty and holds up to 200 lb (91 kg) of sand, and its BASE-13 weighs 75 lb (34 kg) and holds up to 400 lb (181 kg).

When to close it

Close it before the wind gets up. Tuuci, which makes marine-grade umbrellas and tests them to withstand winds up to 50 mph, still does not recommend or warrant using its Ocean Master MAX, Ocean Master M1 and Bay Master umbrellas in wind above 25 mph (40 km/h), or its MAX F-1 and Ocean Master MEGA MAX above 45 mph (72 km/h) even when used with its in-ground anchor. That 25 mph is where the Beaufort scale's force 6, a strong breeze, begins: the Met Office puts it at 22 to 27 knots, and a knot is 1.15 mph, so 25 to 31 mph (40 to 50 km/h). A fresh breeze, force 5, is 17 to 21 knots, or 20 to 24 mph (31 to 39 km/h), and wind forecasts give a mean speed with gusts higher. The calculator tells you to close by 25 mph, as the strictest stated limit of the makers read for this page.

Others give no number, only the habit. Shademaker says no umbrella "regardless of size or weight" should be left open unattended, and in windy conditions it should be closed, taken off its base and stored or laid flat, with the tilt not used in wind, and that wind damage is not covered by its warranty. California Umbrella says "any umbrella should be closed during high winds. No umbrella is engineered to be a sail." Two design choices help: its FAQ notes that fiberglass ribs are "generally more flexible, especially in windy settings" than aluminum ones, and a double-tier canopy has a gap between its layers so "wind passes through instead of catching underneath."

Where the shade goes as the sun drops

Shade from a canopy does not stay under it. The canopy's rim is high above the table, so when the sun is low the shade lands well off to the side. On Shademaker's Libra sheet the rim of the open canopy is 6 ft 6 in (2.0 m) up. A table top at 30 in (0.75 m), which is our assumption, is 1.25 m below that rim, and the shade slides sideways by that height divided by the tangent of the sun's height above the horizon.

Sun height	Shade slides	Share of a 4 ft round table under a 9 ft canopy
20°	11.3 ft (3.4 m)	0%
30°	7.1 ft (2.2 m)	0%
45°	4.1 ft (1.25 m)	58%
60°	2.4 ft (0.7 m)	100%

That is why an umbrella that is perfect at noon leaves you in the sun at five. In London at noon on 21 June the sun is about 62° up, and on 21 December about 15° (the noon height is 90° minus the latitude plus the sun's declination, worked out with the NOAA solar equations the calculator uses). In Phoenix at noon on 21 June it is 80°. The drawings above show it for your table: set the sun height, or give a place, date and time. How the sun moves across your garden explains the sun's track, and shade for hot climates what that means for sun-heavy places. A tilting umbrella lets you turn the canopy toward a low sun, and a cantilever can swing round the table.

Centre pole or cantilever?

A centre pole is the cheaper, lighter and simpler one, and goes through the middle of a table or sits in a base beside it. A cantilever has its pole to one side and an arm over the seats, so nothing is in the middle of the table, and it can tilt and often rotate to follow the sun, but it needs a much heavier base and room. California Umbrella says a 9 ft cantilever needs about 10 to 11 ft of clear space in the direction the canopy reaches, plus 2 ft for the base. A cantilever's canopy is the sold size, so the same 2 ft rule sets it, but a cantilever cannot go through a table, so the calculator switches that option off for it.

A few words you will meet when buying, from the makers' own pages: crank lift and push-button tilt (the common mechanisms), push-up lift (simple, no crank), and collar tilt. California Umbrella's FAQ gives the standard pole as 1.5 in (38 mm), compatible with most bases and with patio tables made for umbrellas, and says its Sunbrella canopy fabric is built on solution-dyed acrylic yarn. Treasure Garden builds with powder-coated aluminum. Ribs are fiberglass or aluminum, as above. For canopy care see how to clean outdoor fabric, and for the full buying picture how to choose a patio umbrella.

If an umbrella is not enough for the space, look at types of awnings and what they cost, louvered pergolas, or, for a south-facing spot, the best shade for a south-facing garden.

Sources, all read on 19 October 2026: California Umbrella, the 2 ft rule and table sizes; California Umbrella FAQ (shade areas, canopy measure, pole, ribs); California Umbrella on cantilevers; Shademaker support and its model pages linked above (minimum base weights, rim height); Treasure Garden bases; Tuuci care and wind limits; Met Office, the Beaufort scale; NOAA solar calculation details; NIST Handbook 44, Appendix C (1 ft is exactly 0.3048 m; 1 lb is 0.45359237 kg).