How Much Fence Does a Garden Actually Need?
The math behind fencing a rectangular garden is the perimeter, not the area. A 30 ft by 20 ft plot looks big at 600 square feet, but you only fence the edge: 2 x (30 + 20) = 100 linear feet. Subtract a 3 ft gate and you need 97 feet of material, then add about 10% for overlap, tensioning, and tie-offs, landing near 107 feet. Buying by the exact perimeter is the single most common way gardeners end up one short roll away from a finished fence.
The Formula and the Post Count
Perimeter = 2 x (length + width) | Fencing = Perimeter - gate width
Posts are spaced every 6 to 10 feet depending on the fence material and wind exposure. For a 100 ft perimeter at 8 ft spacing you need roughly 13 line posts plus two sturdier gate posts, so 15 total. Tighter 6 ft spacing keeps welded-wire or hardware cloth from sagging on windy or sloped sites, while 10 ft spacing is fine for lighter plastic deer netting that carries little load.
Why Height Beats Everything for Deer
A whitetail deer can clear a 7 ft fence from a standing start, which is why wildlife agencies recommend 8 ft fencing for serious deer pressure on open land. In smaller enclosed yards, deer hesitate to jump into a tight landing zone, so a 6 ft fence often holds. Rabbits and groundhogs are a different problem entirely: they go under, not over, so bury the bottom 6 inches of mesh and a 3 ft height is plenty.
Frequently Asked Questions
How do I calculate how much fence I need for my garden?
Measure the length and width of the plot, then use perimeter = 2 x (length + width). Subtract your gate width from that number to get the actual run of fencing, and add about 10% for overlaps, corners, and tensioning. For a 30 by 20 ft garden that works out to roughly 107 feet of material once the gate and waste are accounted for.
How tall should a garden fence be to keep deer out?
For heavy deer pressure on open land, aim for 8 feet, since deer can clear a 7 ft fence with ease. In smaller, enclosed yards a 6 ft fence usually works because deer are reluctant to jump into a confined space they cannot see out of. If a 6 ft fence is failing, add a slanted top wire or build a second offset fence rather than going taller.
How far apart should fence posts be?
Standard spacing is 8 feet, which balances stability and cost for most wire and mesh fences. Drop to 6 ft spacing on windy or sloped sites, or where heavy welded wire would otherwise sag. You can stretch to 10 ft for lightweight plastic deer netting that puts almost no load on the posts.
Does the gate count against my fencing total?
Yes. The gate opening replaces a section of fence, so you subtract its width from the perimeter to find how much fencing material to buy. You will still need two strong gate posts on either side of the opening, which is why this calculator adds them on top of the line posts even though the gate reduces the fence run.
Practical Guide for Garden Fence Length Calculator
Plan your gate location before you order posts. A gate placed on the long side gives you a wider, more comfortable path for a wheelbarrow, while a corner gate wastes less interior space. Whatever you choose, the two gate posts carry the swinging weight of the gate and should be heavier-gauge or set in concrete, unlike the line posts that only hold tension on the mesh.
Match the fence material to the pest and the budget. Welded-wire or hardware cloth is rigid, long-lasting, and rabbit-proof but heavy and pricier per foot. Plastic deer netting is cheap and nearly invisible at a distance, ideal for tall 7 to 8 ft deer barriers, but it tears and needs replacing every few seasons. Many gardeners combine the two: a 2 ft skirt of hardware cloth at the bottom for diggers, topped with netting for height.
Burying the bottom edge is the step most people skip and most regret. Rabbits, groundhogs, and voles dig, so fold the bottom 6 to 12 inches of mesh outward into an L-shape just below the soil, or trench it straight down. This buried apron stops animals that hit the fence and instinctively dig at the base, and it costs only a little extra mesh compared with rebuilding a bed that has been raided overnight.
Quick Checklist
- Measure length and width at ground level, not along a slope, for an accurate perimeter.
- Order roughly 10% extra fencing for overlaps, corners, and tensioning.
- Set heavier gate posts in concrete; line posts can be driven or tamped.
- Bury the bottom 6 to 12 inches of mesh to stop rabbits and groundhogs from digging under.