Raised garden bed calculator

Every line shows the quantity to buy and how StudSheet got it: the spacing, the waste and the package size, so you can check it before the supply house or the quote.

In Canada (2.44 m × 1.22 m raised bed)

Set to Canada, the Sheet works the job out again for Ontario: metric sizes, bag sizes, the frost depth and the code notes. It doesn't just convert feet to meters. The first lines:

• 6 boards, Cedar 2×6: 2 courses of 2×6 (140 mm) for 279 mm × 2 sides: 4 × 2.44 m (1 a board) + 4 × 1.14 m (2 a board).
• 1 post, Cedar 4×4: 4 corner posts a bed = 4, each 279 mm long, 8 from each 2.44 m post.
• ≈32 screws (1 box of 100), Coated deck screws: Two at each board end into the corner posts. Coated or stainless: treated wood eats plain steel, and cedar streaks black around it.
• 1 m³ delivered, Garden soil blend, bulk: 2.44 m × 1.22 m × 279 mm + 10% for settling = 0.91 m³. In bulk it costs far less than 22 bags; have it dumped on a tarp near the beds.

1. Pick a sunny, level spot (6–8 hours of sun for vegetables); level the ground where the boards will sit — no need to dig the whole bed.
2. Cut the boards (96″, 45″) and the posts (11″); pre-drill near the board ends so they don’t split.
3. Build each frame upside down on a flat surface: long boards full length, short boards between them, screwed into the corner posts inside the corners.
4. Set the frame: check it’s square (equal diagonals) and level.
5. Line the bottom with flattened cardboard (tape and labels off), overlapped 6″, and wet it down.
6. Fill: soil to about 1″ below the top; water it in and top it up after it settles.

Must-have tools first, then the ones that help and the ones to rent for the day.

Mistakes that cost a callback or a second trip

• A bed wider than you can reach: Past about 4 ft you end up stepping in and packing the soil. Two narrow beds beat one wide one.
• Long sides with no brace: Wet soil bows a long side outward in a season. A middle post every 8 ft (every 4 ft on tall beds).
• Old railroad ties or CCA lumber: Creosote and arsenic-treated wood don’t belong next to food. Cedar or modern treated lumber.
• Filling with plain topsoil: It compacts into a brick in a raised bed. Use a raised-bed mix or soil blended with compost.

What the calculator assumes

• 1 bed, 8′ × 4′ × 11″: 2 courses of cedar 2×6 (5-1/2″ wide), the short sides between the long ones.
• Boards packed into 8′, 10′, 12′, 16′ lengths with the least lumber bought; long sides past 16′ splice at a middle post.
• Posts the height of the bed, sitting on the ground inside the corners; a middle post every 8 ft of long side (every 4 ft at 22″ and taller); cross-ties on long beds 16½″ and taller.
• Soil: the bed’s volume + 10% for settling (typical); 1.5 cu ft bags, or bulk past about a cubic yard.

The Sheet sets its code notes for the job's state or province. These are New Jersey's and Ontario's; the code reference has more. Always confirm with your building department.

• Permits: a job like this usually needs none, but towns set their own rules. Ask your building department if you're not sure.

What materials do I need to build a raised garden bed?

For the worked example, a 8′ × 4′ raised bed, the Sheet counts 4 lines with waste included, starting with cedar 2×6 (6 boards), cedar 4×4 (1 post), coated deck screws (≈32 screws (1 box of 100)), garden soil blend, bulk (1.25 cu yd delivered). Each line's math is in the table above. Put in your own sizes in the raised bed calculator and every line is counted again.

How long does it take to build a raised garden bed, and can I do it myself?

About 3 to 4 hours for the worked example, in 6 steps. StudSheet stamps it DIY OK: you can do this.

What tools do I need to build a raised garden bed?

14 in all. The must-haves start with circular saw, speed square, cordless drill/driver, impact driver, tape measure (25 ft), carpenter's pencil. On the Sheet you mark each one as owned, to buy or to rent.

Stuck while you build a raised garden bed? Ask in the Raised beds and gardens group of the StudSheet community with this Sheet attached. Homeowners who've done it and verified pros answer, and anyone can read it.

• Landscaping and hardscaping for contractors: run this takeoff at your own prices, send the estimate, and get it signed and the deposit paid.
• Build deck or porch stairs (Stairs for a 3′ rise): Lay out and cut stringers, treads, risers and the landing — to code.
• Deck or balcony (16′ × 12′ deck): Footings, posts, beams, joists and decking for a deck, or a balcony on posts, with the railing it needs.
• Railings and guards (12′ wood railing): Wood, aluminum, steel, glass or cable railings for decks, balconies, porches and stairs: posts, panels, hardware and the height rules.
• Fence (100′ wood fence, 6′ tall): Posts, rails, pickets or panels, concrete and gate hardware for a wood, vinyl or aluminum fence.
• All 45 Sheets, across 16 trades.
• Code reference: frost depths, guard heights, stairs, retaining walls.