How do I work out how much fencing wire to buy?
Measure every side of your lot and add them up for the perimeter, then subtract gate openings. Cyclone wire comes in 10-meter rolls, so divide the fence length by 10 and round up. Barbed wire comes in 140-meter rolls, so multiply the fence length by the number of strands, then divide by 140 and round up. Add about 5% for corners and overlaps.
Fencing is bought by running length, not by area. A lot of 600 square meters can need very different amounts of wire depending on its shape and where the gates go. That makes the perimeter the one number you need before you ask for a quote on cyclone wire or barbed wire.
What You Need to Measure
- A 30 m or 50 m measuring tape, or a measuring wheel for long lots
- Stakes and string to mark straight lines on uneven ground
- A pen and a sketch of the lot, with each side labelled
- Your lot plan or title (technical description), if you have it, to check your numbers
Step 1: Measure Every Side of the Lot
Walk the line where the fence will actually stand, not the line on the title. Measure each side from corner to corner and write it on your sketch. If the ground slopes, hold the tape level or follow the ground; the wire follows the ground, so use the longer figure.
- Rectangular lot: perimeter = 2 × (length + width).
- Irregular lot: measure every side separately and add them all up.
- Lot with a concrete wall on one side: measure only the sides that need new wire, or the wall length if you will run barbed wire along its top.
The distance tool in Google Maps is fine for a rough budget, but measure on site before you order.
Step 2: Subtract Gates and Open Sides
Gate openings do not need fence wire. Subtract each gate width from your perimeter. A single driveway gate is often 3 to 4 meters, and a walk-in gate about 1 meter. This number is your fence length.
Step 3: Add an Allowance
Add about 5% to the fence length for overlaps at the ends of rolls, corners, and wire that gets cut off when you tension it. For lots with many corners, use 7 to 10%.
Step 4: Convert Length to Rolls
Cyclone wire (10 meters per roll)
Rolls needed = fence length with allowance ÷ 10, rounded up. Pick the height first: 4 ft (1.2 m), 5 ft (1.5 m) or 6 ft (1.8 m). Each roll is G.I. #12 wire with a 2×2-inch diamond mesh.
Barbed wire (140 meters per roll)
Barbed wire is run as several strands, one above the other. Total wire = fence length × number of strands. Rolls needed = total wire with allowance ÷ 140, rounded up.
- 3 strands is common for the top of a wall or a cyclone wire fence.
- 4 to 5 strands is common for farm boundaries and livestock.
As a rule of thumb, one 140 m roll makes about 46 meters of a 3-strand fence, or 28 meters of a 5-strand fence.
Worked Example: 20 m × 30 m Lot
| Step | Calculation | Result |
|---|---|---|
| Perimeter | 2 × (20 + 30) | 100 m |
| Less one 4 m driveway gate | 100 − 4 | 96 m of fence |
| Add 5% allowance | 96 × 1.05 | 100.8 m |
| Cyclone wire rolls | 100.8 ÷ 10 | 11 rolls |
| Barbed wire, 3 strands | 96 × 3 × 1.05 = 302.4 m; ÷ 140 | 3 rolls |
| Barbed wire, 5 strands | 96 × 5 × 1.05 = 504 m; ÷ 140 | 4 rolls |
| Posts at 2.5 m spacing | 96 ÷ 2.5 = 38.4, round up, plus 2 gate posts | about 41 posts |
At the September 2026 prices on our cyclone wire price guide, 11 rolls cost ₱23,100 (4 ft), ₱28,600 (5 ft) or ₱33,000 (6 ft). Three rolls of barbed wire at ₱2,300 each come to ₱6,900. Prices change with the steel market, so confirm them when you ask for a quote.
Quick Reference by Lot Size
These figures include the 5% allowance and assume no gates. Subtract your gate openings first if you have them.
| Lot size | Perimeter | Cyclone wire rolls | Barbed wire rolls, 3 strands | Barbed wire rolls, 5 strands |
|---|---|---|---|---|
| 10 m × 20 m | 60 m | 7 | 2 | 3 |
| 15 m × 20 m | 70 m | 8 | 2 | 3 |
| 20 m × 30 m | 100 m | 11 | 3 | 4 |
| 25 m × 40 m | 130 m | 14 | 3 | 5 |
| 50 m × 50 m | 200 m | 21 | 5 | 8 |
| 100 m × 100 m (1 hectare) | 400 m | 42 | 9 | 15 |
Counting Posts
Divide the fence length by the post spacing and round up, then add posts for gates and corners. For barbed wire, space posts 2 to 3 meters apart, or 1.5 to 2 meters on slopes or where animals lean on the fence. See our barbed wire fencing guide for tensioning and bracing at corners and gates.
Common Mistakes
- Forgetting the strands. Ordering one roll length of barbed wire per fence length gives you a single strand.
- Measuring the title, not the fence line. The fence usually sits a little inside the boundary.
- Not subtracting gates, or not adding the gate posts.
- Skipping the allowance. Running short by a few meters means a second delivery.
- Rounding down. Always round rolls up. Part of a roll cannot be bought.
Frequently Asked Questions
How many rolls of cyclone wire do I need for 100 meters?
10 rolls cover exactly 100 meters. With a 5% allowance for corners and overlaps, order 11 rolls.
How many meters are in a roll of cyclone wire and barbed wire?
Our cyclone wire comes in 10-meter rolls (4, 5 or 6 ft high). Our barbed wire comes in 140-meter rolls of #12 gauge wire.
How much barbed wire do I need for a 3-strand fence?
Multiply the fence length by 3 and divide by 140. For 100 meters of fence that is 300 ÷ 140, about 2.1, so order 3 rolls.
Do I need to subtract the gate from the perimeter?
Yes. Gate openings do not need fence wire. Subtract each gate width, but add gate posts to your post count.
Can I use the same measurement for cyclone wire and barbed wire?
Yes. Both are based on the fence length. If you run barbed wire on top of a cyclone wire fence, use the same fence length for both.
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Tell us the perimeter, gate widths, fence height and number of strands, and our team will give you the roll count and price.
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