12 x 40 ft rectangular pool
pool plan
A lap-class pool: long, narrow and uniformly deep, built for exercise. The constant depth makes flip turns predictable and halves the excavation surprises; the narrow width keeps volume — and therefore heating — in check for the length you get.
The rectangle is the default for a reason: it gives you the most swimmable water for a given footprint, plays well with modern architecture and lap swimming, and makes covers, solar blankets and automatic cleaners simple. Straight walls also keep formwork and tiling straightforward, which builders appreciate.
Open in the 3D designerFree · no signup · runs in your browser
12 × 40 ft — shown to scale
The numbers, computed
- Water surface
- 480 sq ft
- Water volume
- 14,372 gal (60.0 tons)
- Perimeter
- 104′
- Depth
- 4′ 5″–4′ 5″
- Excavation approx.
- 124 cu yd
- Fill time (garden tap)
- 36 hours
- Skimmers needed
- 2×
- Heat pump size
- 68,000 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: 12 × 4 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 | $44,000–$66,000 | Fastest and least expensive; the liner is replaced every 8–12 years. |
| Fiberglass | $59,000–$85,000 | One-piece shell, quick install; limited to sizes and shapes a mould exists for. |
| Concrete (gunite) | $69,000–$110,000 | 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 12 × 40 ft pool hold?
- About 14,372 gal (60.0 tons of water) at 4′ 5″–4′ 5″ depth — computed from the actual pool outline, not a rule of thumb.
- How long does it take to fill?
- Roughly 36 hours 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 480 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 12 × 40 ft rectangular pool cost to build?
- Roughly $44,000 to $110,000 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
15 × 30 ft · Rectangular
Family pool15,118 gal · 450 sq ft
16 × 32 ft · Rectangular
Family pool17,200 gal · 512 sq ft
10 × 40 ft · Rectangular
Lap pool11,977 gal · 400 sq ft
14 × 28 ft · Rectangular
Family pool13,169 gal · 392 sq ft
15 × 30 ft · Oval
Family pool11,722 gal · 352 sq ft
16 × 36 ft · Rectangular
Estate pool20,739 gal · 576 sq ft
Go on — put a pool in your garden.
Open the designer and see it in 3D tonight. Free, no signup.
Start designing — it's freeFree · no signup · runs in your browser