Difference Between String Trimmer and Edger | Choose The Right Tool

A string trimmer cuts with a spinning nylon line for versatile trimming and edge maintenance, while a lawn edger uses a vertical metal blade to carve deep, crisp borders that a trimmer cannot create.

Standing in the aisle with both tools on the shelf, the difference comes down to one question: do you need to maintain edges or create them? A string trimmer handles weeds, tall grass, and routine edging around obstacles. A lawn edger cuts a clean trench along sidewalks and driveways. Most homeowners end up wanting both, but which one you buy first depends on what your lawn actually looks like today.

How They Cut: Line vs. Blade

The cutting mechanism is the most basic difference. A string trimmer spins a flexible nylon line horizontally or at an angle, trimming grass and weeds at the surface. An edger spins a vertical metal blade that digs into the soil to cut roots and create a defined separation between lawn and hardscape.

This mechanical difference decides what each tool can do. The trimmer’s line is versatile but shallow. The edger’s blade is aggressive but single-purpose.

What Each Tool Can Actually Do

What A String Trimmer Handles

A string trimmer is the tool for spots the mower cannot reach — along fence lines, around trees, between flowerbeds, and against walls. It cuts grass and light weeds in these areas quickly. Many trimmers also edge by tilting the head vertically, which works for maintaining an existing edge along sidewalks and driveways.

A trimmer cannot carve a new edge where grass has grown over the pavement or where a new flowerbed border needs cutting. The nylon line lacks the rigidity and depth to cut through soil and roots.

What A Lawn Edger Handles

An edger cuts a clean, deep trench — up to 4.5 inches deep — along sidewalks, driveways, and garden beds. It reclaims overgrown borders where grass has crept onto pavement. It creates the sharp line that makes a lawn look professionally maintained.

An edger cannot trim grass in tight spots around trees or bushes. The vertical blade and wheeled guide make it too rigid for that work. It is a one-job tool, but it does that job better than anything else.

String Trimmer vs. Edger: Side-By-Side Comparison

Which Power Source Makes Sense For You

Both tools come in gas, corded electric, and cordless battery versions. Each has trade-offs that matter for your yard size.

Gas trimmers and edgers offer the most power for large properties. Two-cycle models require mixing oil and gas in a separate fuel container. Four-cycle models use straight gas with a separate oil reservoir. Both need routine maintenance and produce more noise and fumes.

Corded electric tools are lighter and start instantly, but the cord limits your reach to about 100 feet from an outlet. Cordless battery models give you freedom to roam but lose power faster when used for edging compared to trimming. A cordless trimmer is an excellent choice for most suburban lots — the best cordless trimmer edger combinations this year balance runtime and cutting power for both jobs.

Can One Tool Do Both Jobs Well?

Some string trimmers include a head that rotates 90 degrees into an edging position. This lets you maintain an existing edge without switching tools. The Troy-Bilt TB25CB curved shaft model and the BLACK+DECKER 20V MAX are common examples that offer this dual mode.

The limitation is clear: a trimmer in edging mode still uses nylon line, not a blade. It can touch up an edge but cannot cut a new one or dig deep enough to reclaim an overgrown border. For routine edge maintenance after mowing, it works fine. For creating a fresh line or restoring a buried sidewalk edge, you need a dedicated edger.

Common Mistakes To Avoid

Most mistakes come from misunderstanding the tool’s limits. Using a string trimmer to try to create a new edge is the most common — it simply does not have the cutting depth or rigidity. The line bounces off the soil and leaves a ragged result.

Another frequent error is assuming an edger can double as a trimmer. The vertical blade and wheeled base make it useless for reaching under shrubs or cutting grass around a tree trunk. Each tool has its zone, and stepping outside it costs time and frustration.

Cordless trimmers also struggle more with edging than corded models. The motor works harder against the line’s angle, draining the battery faster. If your yard needs significant edging work, a gas or corded electric edger or a high-capacity cordless trimmer is the better investment.

Pricing: What You Will Spend

String trimmers generally cost more because they offer more versatility. A decent gas or electric edger is not expensive, and it provides a much cleaner edge in less time than any trimmer can manage. If you only buy one tool today, the trimmer wins for general yard work. If your lawn already looks good but lacks that crisp, professional border, the edger delivers the biggest visual upgrade per dollar.

Which Tool To Buy First

Your lawn’s current condition decides this. If you have weeds, overgrown grass in corners, and a general look that needs cleaning up, buy a string trimmer first. It handles the majority of post-mowing cleanup and gives you the most value for your money.

If your grass is already manageable but the edges along your driveway and flowerbeds are ragged and overgrown, an edger will transform the look of your yard more dramatically. A manual edger is the cheapest entry point if you only need to define one or two borders, but a gas or electric model saves serious time on larger properties.

For perfectionists and professionals, the answer is simple: own both. Trim first to cut everything down, then edge to create the sharp lines that make a lawn look its best.