Landscape edging calculator

How many feet of no-dig coil edging a bed takes — counting the arc of every curve, not the straight line across it — plus the coils to order and the anchoring stakes, with curve spacing set by the radius instead of a flat rate.

01 How the math works

The length is two parts added together. The straight run is the tape measurement. The curved part is the arc — a curve of radius R turning through angle θ measures R × θ with θ in radians, which is longer than the straight line across the bend. Coils are the total length divided by the coil you buy, rounded up. Each coil after the first needs a connector to join it to the last.

Stakes are where the flat-rate calculators stop short. On a straight run you stake at the manufacturer's maximum — 40 in (1,016 mm) on center for a Dimex EasyFlex coil. On a curve the coil fights back: it keeps the bend-back memory of being rolled, so the straight line between two stakes bows off the arc. Hold that bow to a tolerance and the geometry fixes the spacing:

That is the chord of a circular segment whose middle sits one bow-tolerance off the arc. The tighter the radius, the shorter the chord, the more stakes. We count one stake per spacing interval on each part, plus one to pin the far end.

02 Worked example

Take a bed border that runs 24 ft (7.32 m) straight, then rounds a planting bed on a 2 ft (0.61 m) radius through a quarter turn (90°), edged with a Dimex EasyFlex no-dig coil.

The curve is 2 × 90 × π ÷ 180 = 3.14 ft (0.96 m) of arc, so the edging totals 24 + 3.14 = 27.14 ft (8.27 m) — one 100 ft (30.48 m) coil, no connector.

Stakes split by shape. The straight run takes ⌈24 ft ÷ 40 in⌉ = 8. The curve, at a 1/2 in (12.7 mm) bow, wants a stake every 2 × √(2 × 24 in × 0.5 in − 0.5 in²) = 9.75 in (248 mm), so its 3.14 ft of arc takes 4 more. Add one to pin the end: 13 stakes. A flat-rate calculator spacing everything at 40 in would call it 10 — three stakes short, all of them on the corner that needed them most.

03 When this calculator is wrong

The count holds a few assumptions. Three places it and the finished bed part ways:

• The bundled stake count is a straight-run number. A Dimex EasyFlex 100 ft kit ships 30 spikes — one every 40 in (1,016 mm), which is the straight-run maximum and nothing more. A bed with real curves blows past that: the worked example above needs 13 stakes for 27 ft, a rate that would want roughly 48 over a full 100 ft coil of similar bends. Buy loose spikes to cover the curves, or the kit runs out at the first corner.
• The bow tolerance is a choice, not a spec. We default to 1/2 in (12.7 mm) of bulge off the arc between stakes, which keeps a visible curve crisp. Tighten it to 1/4 in (6.35 mm) for a formal edge and the 2 ft radius spacing drops to about 6.9 in (175 mm), nearly doubling the curve stakes. There is no code here — set the tolerance to how sharp you want the line to read.
• No-dig coil edging is not paver edge restraint. This page sizes the stakes that hold a bed border against the coil's own spring-back. A paver field pushes back with the weight of traffic and needs a rigid restraint spiked far tighter — about 6 in (150 mm) on center on curves, per ICPI/CMHA Tech Spec 3. Use the paver calculator for a patio, not this one.

04 What to do with the result

Order the length to the arc, never the chord, and round the coil count up — the cost of a second coil you half-use is a few dollars; the cost of splicing in a 6 ft offcut mid-curve is a joint that shows. The same rule runs on the stakes: the calculator gives a working minimum, so add a handful for the curves and the spots where the ground is soft and the first stake won't bite. The one place to overbuy is the corners.

Set the edging in the sun for an hour before you lay it so the coil relaxes and stops fighting the curve, pin the ends and the tightest part of each bend first, then fill in the straight runs to the on-center figure. Driving the spikes flush with the tab — not past it — is what keeps the top edge from rippling along the line.

05 Common questions

How much landscape edging do I need?

The straight runs plus the arc of every curve. A curve of radius R through angle θ is R × θ ÷ 57.3 feet (θ in degrees), which is longer than the straight line across it — a 2 ft (0.61 m) radius quarter-circle is 3.14 ft (0.96 m), not 2 ft. Add the parts, then divide by the coil length and round up.

How far apart should landscape edging stakes be?

On a straight run, no wider than the manufacturer's maximum — 40 in (1,016 mm) on center for a Dimex EasyFlex coil. On a curve, closer, because the coil tries to straighten: the spacing falls as the radius tightens. A 2 ft (0.61 m) radius wants a stake about every 9.75 in (248 mm); a gentle 10 ft (3.05 m) radius stays near the 21.9 in (556 mm) mark.

How many stakes come with a roll of edging?

A Dimex EasyFlex 100 ft kit includes 30 spikes and 5 connectors; the 40 ft kit has 12. That is one spike per 40 in — enough for a straight run and short for a curvy bed. Count your curves before you trust the box.

How long is a roll of landscape edging?

No-dig coil edging is commonly sold in 20, 40, and 100 ft (6.1, 12.2, 30.48 m) coils. Enter the coil you are actually buying — the calculator divides the total length by it to count coils and connectors.

Do I count the last stake at the end of the run?

Yes. A run with two free ends is anchored at both, so it takes one more stake than it has spacing intervals. If the edging closes back on itself around an island bed, drop one stake — the two ends share an anchor.