Garden Edging Calculator

How this is calculated

Edging is bought by the linear foot, so the whole calculation is the length of the boundary you are actually edging. For a rectangular bed the full perimeter is twice the length plus twice the width. But a bed rarely needs all four sides: one against a wall, a fence or a path with its own edge needs only the exposed ones. The sides input handles that, and it is where most of the saving is. ⚠️ CURVES USE MORE THAN YOU MEASURE ACROSS THEM. If your bed has a curved front, the edging follows the curve rather than the straight line between its ends, so a curve always needs more material than the dimension suggests. Measure a curve by laying a hose or a rope along the line you want and then measuring the rope. Guessing a curve from its width consistently under-orders. WASTE IS DIFFERENT FROM MOST MATERIALS HERE, because the offcut from one run is often usable at the start of the next. That is why the allowance is low - five percent is usually plenty for straight runs, and ten if you have several separate beds where each one starts with a fresh piece. STAKES ARE THE PART PEOPLE UNDER-BUY. Flexible plastic and metal edging needs anchoring roughly every 3 feet, and more often on curves, where the material is trying to spring back straight. The default here is one every 3 feet plus one extra per corner. Under-staked edging looks fine on the day it goes in and lifts out of the ground over the first winter, which is the commonest way an edging job fails. DEPTH DECIDES WHETHER IT WORKS. Edging that sits proud of the soil looks tidy and stops nothing; grass simply grows over and through it. To act as a barrier against creeping grass it needs to be set deep enough to intercept the runners, and the manufacturer's stated depth is the figure to follow rather than however deep the trench happens to be. What this does not include: the trench itself, which is most of the labour, and a spade edge, which is the free alternative. A cut edge - a clean vertical slice with a half-moon edger, no material at all - is what a great many gardens use, costs nothing and looks excellent. It just needs redoing once or twice a year, and this calculator exists for people who have decided against that.

Common questions

Do I need edging on all four sides?

Very often not, and this is where the money is. A bed running along a house wall, a fence or a paved path with its own edge needs only the exposed sides - typically three, sometimes two for a corner bed, sometimes just the front. Working this out before ordering routinely cuts a quarter or a third off the material, and the calculator shows what you saved for exactly that reason. Look at the bed rather than at its dimensions.

How do I measure a curved bed?

Lay a hose or a length of rope along the line you want the edging to follow, then pick it up and measure the rope. That gives you the real length. Estimating a curve from the straight distance across it under-orders every time, because the curve is by definition longer than the chord - and the error grows with how pronounced the curve is. This is the single most common way an edging order comes up short.

Why is the waste allowance so low?

Because offcuts are usually reusable here, unlike most materials. The piece left over at the end of one run generally starts the next one, so five percent is plenty for a single bed with straight runs. Ten percent is more realistic if you have several separate beds, since each one begins with a fresh piece and the leftovers may be too short to start another. That is a different situation from tile or flooring, where an offcut is frequently useless.

How many stakes do I actually need?

More than come in the box, which is the recurring complaint about edging kits. Roughly one every 3 feet is the usual guidance, closer on curves where the material is under tension trying to spring back straight, plus one at each corner. Buy them generously - under-staked edging looks perfect on the day it goes in and lifts out of the ground over the first winter as the soil freezes and thaws. That is the commonest way an edging job fails, and stakes are the cheapest part of it.

How deep should edging go?

As deep as the manufacturer states, and the reason matters: edging that sits proud of the soil looks tidy and stops absolutely nothing, because grass simply grows over and through it. To work as a barrier against creeping grass it has to be set deep enough to intercept the runners travelling sideways through the top few inches of soil. Digging the trench properly is most of the labour on this job and most of whether it works.

Do I need edging at all?

Genuinely often not. A cut edge - a clean vertical slice made with a half-moon edger, no material whatsoever - is what a great many gardens use, costs nothing, and looks excellent. Its only downside is that it needs redoing once or twice a year. Installed edging buys you that maintenance back and gives a harder barrier against creeping grass. It is a real trade rather than an upgrade, and it is worth making deliberately before spending anything.

Take it further with AI

Copy this into ChatGPT or Claude with your own numbers filled in. It hands over the figures this calculator worked out, so the answer is built on real arithmetic instead of a guess.

I used the Garden Edging Calculator at https://www.bfcbrilliance.com/tools/garden-edging-calculator.

What I entered:
- Bed length (ft): ___
- Bed width (ft): ___
- Sides needing edging: ___
- Waste allowance (%): ___
- Length per piece or roll (ft): ___
- Stake every (ft): ___

What it calculated:
- Edging needed: ___
- — before waste: ___
- Pieces or rolls to buy: ___
- Stakes needed: ___
- Full perimeter, for comparison: ___

Use those figures as given — they are already worked out, so please don't recalculate or estimate your own. Help me turn them into a plan: what to buy or do, in what order, roughly what it should cost, and the mistakes people most often make with this job.

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