18 x 36 ft rounded rectangle pool
pool plan
An estate-class pool: resort presence at home, with room for swimming, play and lounging at the same time. At this size the supporting decisions matter as much as the basin — plan generous decks, a solid heat source and an automatic cover from day one, because every square metre of water is heated, treated and covered.
A rounded rectangle keeps almost all of the rectangle's swimmable water but rounds the corners into generous fillets. The result reads softer in a garden, is gentler on swimmers, and the corners no longer trap debris the way sharp ones do. It's the shape we default to in the designer.
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18 × 36 ft — shown to scale
The numbers, computed
- Water surface
- 635 sq ft
- Water volume
- 22,470 gal (93.8 tons)
- Perimeter
- 101′ 5″
- Depth
- 3′ 11″–6′ 7″
- Excavation approx.
- 184 cu yd
- Fill time (garden tap)
- 2 days
- Skimmers needed
- 3×
- Heat pump size
- 102,000 BTU/h
Figures are computed from the sampled pool outline and the plan's depths — the same geometry the 3D designer uses. Excavation includes shell and working allowance; your site conditions may differ.
Also in metric sizes: 10 × 5 m
What it costs to build
A rough installed-cost range per construction type, at this size — the pool itself, with basic coping. Not a quote.
| Construction | Installed cost | Note |
|---|---|---|
| Vinyl liner | $52,000–$78,000 | Fastest and least expensive; the liner is replaced every 8–12 years. |
| Fiberglass | Not made at this size | One-piece shell, quick install; limited to sizes and shapes a mould exists for. |
| Concrete (gunite) | $79,000–$129,000 | Built to any shape or size; the slowest build and the most upkeep. |
Rough 2026 estimates for the pool installed with basic coping — excavation, shell and basic equipment. Excludes deck, fencing, landscaping, heating and permits, all of which vary by site and by builder; get real bids before budgeting from these figures.
Questions about this plan
- How much water does the 18 × 36 ft pool hold?
- About 22,470 gal (93.8 tons of water) at 3′ 11″–6′ 7″ depth — computed from the actual pool outline, not a rule of thumb.
- How long does it take to fill?
- Roughly 2 days from a standard garden tap (~6.6 GPM). A water delivery service fills it in a few hours.
- Is this size right for my garden?
- The water surface is 635 sq ft; plan roughly 1.5–2× that footprint including the surrounding deck. Open the plan in the designer and set your own deck margins to see the full footprint.
- Can I change the depth or edge type?
- Yes — open the plan in the designer and adjust depths, edge system (skimmer, deck-level overflow or raised), finishes and accessories freely.
- How much does the 18 × 36 ft rounded rectangle pool cost to build?
- Roughly $52,000 to $129,000 installed at this size, depending on construction type — before deck, fence, landscaping, heating or permits. See the cost table above for the range per type.
Similar pool plans
18 × 36 ft · Rectangular
Estate pool23,353 gal · 648 sq ft
18 × 36 ft · Oval
Estate pool17,369 gal · 507 sq ft
18 × 36 ft · Roman
Estate pool20,656 gal · 578 sq ft
18 × 36 ft · Grecian
Estate pool21,720 gal · 611 sq ft
18 × 36 ft · L-shape
Estate pool18,506 gal · 526 sq ft
18 × 36 ft · Lazy L
Estate pool19,906 gal · 592 sq ft
Go on — put a pool in your garden.
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