Shade sail size for a patio
Updated: 16.10.2026
The listing you like says 3 x 3 m. That number is not the patch of shade you will get, and it is not a sail you can stretch across a 3 m gap. The shade sail size for a patio is the anchor span, minus room to tension, minus the curve that pulls the sides inward. This page does that arithmetic for the sizes in our [sun sail comparison](/hub/sun-shades/sun-sail). It does not pick a brand. The Products Compared editorial team used stored amazon.co.uk listing text and UK seller rules as they stood on 16 October 2026. We did not measure your garden.
The listing you like says 3 x 3 m. That number is not the patch of shade you will get, and it is not a sail you can stretch across a 3 m gap.
The listing you like says 3 x 3 m. That number is not the patch of shade you will get, and it is not a sail you can stretch across a 3 m gap. The shade sail size for a patio is the anchor span, minus room to tension, minus the curve that pulls the sides inward. This page does that arithmetic for the sizes in our sun sail comparison. It does not pick a brand. The Products Compared editorial team used stored amazon.co.uk listing text and UK seller rules as they stood on 16 October 2026. We did not measure your garden.
Our top picks
| Badge | Product | Shape | In the box | Fabric | Note | Price | Offer |
|---|---|---|---|---|---|---|---|
| Best overall |  Mokani Mokani 3 x 4 m rectangle | Rectangle | Sail, 6 ropes, bag, 2 turnbuckles, 2 carabiners, 4 pad eyes, 16 screws and plugs | Polyester, PU, 160 g/m² | 8.0 | about £41.99 | View offer |
| Alternative |  Mokani Mokani 3 x 3 m rectangle | Rectangle | Sail and 6 ropes | Polyester, PU, 160 g/m² | 7.8 | about £30.99 | View offer |
| Preis-Tipp |  HEYOMART HEYOMART 2 x 2 m square | Square | Sail, 4 pad eyes, 4 ropes of 200 cm | Polyester, PU, 160 gsm | 7.0 | about £19.99 | View offer |
On this page
Measure the anchors, not the slabs
Measure from the points you will actually fix into, not from the edge of the paving. Write down each side and the diagonal. If the post is not in the ground yet, you are planning a structure. HEYOMART measures corner to corner, so a 2 m table can still sit partly in the sun.
Leave room to tension
The sail has to be shorter than the anchor span so ropes or turnbuckles can pull it. Sellers publish different gaps, and they are a range of rules rather than one correct allowance you can average. ManoMano’s UK guide says allow a minimum of 30 cm between the anchor points and the corners. On the listings here, RICHIE and the Mokani 3 x 4 m page say leave 1.5–2 ft, about 45–60 cm. Ghligna says 30–45 cm between the fixing points and the D-rings.
A 3 m gap between two walls is a rule of thumb, not a standard. A 3 x 3 m sail has no leftover length for hardware. If you allow 40 cm at each end of one side, the cloth on that side wants to be about 2.2 m, not 3 m. KAHEIGN’s ropes are only 1 m long, so they cannot bridge a large allowance. None of the ready sizes grows to fill a gap that is already the same length as the title. Drilling and slope are on how to install a shade sail.
The curve is not extra shade
After you have subtracted the hardware gap, subtract the curve. The sides are cut inward so the sail can tension. The middle of a side is narrower than the corner-to-corner title. HEYOMART states that the published size is the distance between the corner tips, not the width of the shaded cloth. One UK review of that 2 x 2 m square measured 1.42 m across the middle of a 2 m side. A RICHIE review of a 2 x 3 m sail puts the shaded patch at about 1.4 m by 2.4 m. A KAHEIGN review of a 2.5 x 3 m sail puts the middle about 200 mm under the stated size. Those three notes are the only shaded-width measurements stored for this set. Do not copy the 1.42 m figure onto the Mokani, Ghligna, YOUNTHYE or DAJAVE sails. The cut differs, so measure your own belly.
When the listing disagrees with itself
Some pages do not offer one size to measure against. ABTZENO at about £12.99 says 3.2 x 3.2 x 4.5 m in the title, 3 x 4 m in the size field, and 40 x 30 cm in the item dimensions. You cannot subtract a hardware gap from three different numbers.
DAJAVE’s 3 x 4 m rectangle and 3 m triangle both print item dimensions of 10 x 10 mm, against weights of 1.62 kg and 1.33 kg. The millimetre field is a conflict, not a sail size. Ghligna’s 3 x 3 m title sits next to a 30 x 30 mm dimension attribute. Do not use a 10 g weight or a 10 mm field in your arithmetic. Where the title and the dimension field do agree, you still apply the gap and the curve. A consistent 3 m is not a 3 m shade.
Common questions
Do I measure the patio or the fixing points?
Measure the fixing points. The patio slabs tell you where people sit, not where the rings will land. A post set in from the boundary, or a wall plate beside a window, shortens the span. If you have not chosen the anchors, you do not yet have a sail size. Furniture measurements come after the belly, not instead of the anchors.
How much smaller should the sail be than the gap?
Shorter on every side you will tension, by whatever hardware you will actually use. Seller rules in front of you run from about 30 cm, through 30–45 cm and 1.5–2 ft, up to about 10 percent of the side. They are not one averaged number. A 3 m gap does not accept a 3 m sail. Subtract at least the ropes or turnbuckles in your box, and stop if the remainder is longer than the cloth you can buy.
Why is the middle narrower than the title?
The sides are curved so the sail can pull tight. HEYOMART says the size is corner to corner, and the stored reviews put the middle well under that title. Tension does not straighten those edges back to the corner measurement.
Will a 3 x 3 m sail cover a 3 m pergola?
Not as a taut, full cover. The sail has to stop short of the beams so you can attach ropes or turnbuckles, and the curved sides shade less than the corner measurement. If the beams are 3 m apart, look at a smaller title size or move the anchors further apart. Forcing the rings onto the beams leaves a slack belly that holds rain.
What if the listing prints two sizes?
Do not pick the larger one because it matches your patio. ABTZENO prints three. DAJAVE and Ghligna print millimetre dimensions that cannot be the sail. Use a listing whose title and dimension fields describe the same metres, then apply the gap. If you cannot tell what will arrive, the tape measure cannot finish the job.
Related pages
Sources
Public UK sources used for this comparison. Listing prices, stars and review counts are the amazon.co.uk figures stored on 16 October 2026.
- NHS — sunscreen and sun safety (retrieved 16.10.2026)
- Cancer Research UK — sun safety (retrieved 16.10.2026)
- GOV.UK — permitted development rights for householders: technical guidance (retrieved 16.10.2026)
- Planning Portal — gazebo or awning (retrieved 16.10.2026)
- Consumer Rights Act 2015, section 9 (retrieved 16.10.2026)
- BSI — BS EN 13561:2015 external blinds and awnings (retrieved 16.10.2026)
- Maanta UK — how to choose a shade-sail fabric (retrieved 16.10.2026)
- Shade Sail Boutique — wind (retrieved 16.10.2026)