String Trimmer vs Edger: Which Do You Need?

String Trimmer vs Edger: Which Do You Need?

ByKen

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If you are weighing a string trimmer vs edger, the short answer is this: a string trimmer cuts grass and weeds with a spinning line and reaches around posts, fences and bed edges, while an edger cuts a firm line between the lawn and a walk, drive or patio. Some battery models combine both jobs. This post is for people with small to mid-size yards who want to know which tool type fits their edges and what each listing includes. It covers three picks from a pool of six listings, and it says where the listings and sources do not give the figures you may want.

Quick answer

  • Pick a string trimmer for grass and weeds around posts, trees and fences. The Virginia Tech guide describes it as a tool that uses a flexible monofilament line for cutting grass and similar plants around stationary objects (Source 1).
  • Pick an edger for a cut along a paved edge. The same guide describes a lawn edger as a tool used to separate a lawn from a walkway or other paved surfaces (Source 1). Only one dedicated edger is in this pool.
  • Check the box first. The Ryobi bare tool and the worksky edger do not include a battery or charger. The RAXONE includes two 2.5Ah batteries and a fast charger.
  • If you want both jobs from one tool, look for a head that turns. Black+Decker’s guide says its combination models let you flip the head to vertical for wheeled edging (Source 4).

The two tools compared

The two tools do different jobs, and the source text shows where the line falls. Virginia Tech’s guide defines a string trimmer as a hand-held device with a flexible line head for grass and weeds around stationary objects (Source 1). It defines a lawn edger as a garden tool that separates a lawn from a walkway or other paved surfaces (Source 1). The same guide also says edgers with metal blades can cut through underground objects, splinter concrete and cause sparks (Source 1).

The guide’s use rules are short. A string trimmer should be used only for trimming weeds and grass (Source 2). A lawn edger should not be used on gravel surfaces (Source 1). A string trimmer is the closer match for weeds around posts and trees, and an edger is the closer match for a line along a paved edge.

Many newer battery models combine both jobs. Black+Decker’s guide says its combination trimmers and edgers let you “flip the cutting head from a horizontal position to vertical for wheeled edging” and switch back again (Source 4). That guide does not compare the combination edge with a dedicated edger, so this post does not treat the two as equal.

The table below puts the three picks side by side. It uses only figures the listings state, plus the Ryobi page where it is marked. Gaps are marked not stated. The table is a fact sheet, not a ranking.

Product Battery in the box Battery platform Cutting width or blade Weight Speed or motor Runtime claim Source
RYOBI 40V 15 inch string trimmer, bare tool Not included. The listing says Battery and Charger Sold Separately. 40V (listing bullet) 13 inches (listing field); title says 15 inch 11 pounds 8500 rpm Up to 71 minutes on a 40V 4Ah battery; the manufacturer states this Listing; Source 3
RAXONE 21V 2-in-1 string trimmer and edger Two 2.5Ah batteries and a fast charger (listing) 21V (listing title) 12 inches 6.2 pounds 9500 rpm not stated Listing
worksky 9 inch lawn edger, tool only Not included. The listing says No battery and charger. Listing claims compatibility with a Milwaukee 18V battery 9 inch steel blade; cutting depth 1.3 to 1.75 inches 7.2 pounds 3500 rpm; 800w motor (listing bullet) not stated Listing

String trimmer picks

Four items in the pool are string trimmers or string trimmer heads. Two are picked. The other two are left out for the reasons under How we chose. The picks are placed by their own titles and bullets, not by the side label they carried. For a side-by-side of two string trimmer lines, see Greenworks vs EGO Power+ string trimmers compared.

RYOBI 40V 15 inch string trimmer, bare tool

The listing says this is a 40V model with EXPAND-IT attachment capability. It gives up to 71 minutes of runtime on a 40V 4Ah battery, a weight of 11 pounds and a speed of 8500 rpm. Tool-only flag: yes. The listing says the battery and charger are sold separately, so the box holds the tool without either one.

The cutting width is the one figure that disagrees. The title says 15 inch, and the cutting width field says 13 inches. This post shows both and does not choose between them.

The Ryobi page for this model, RY40205BTLVNM, shows two options: “Tool Only” and “(1) 4Ah Battery/Charger” (Source 3). The same page marks the model “Discontinued,” so check availability before you plan a purchase. The manufacturer states up to 71 minutes of runtime on a 40V 4Ah battery. The listing does not say how runtime changes with grass, height or terrain.

The page also says “More power than a 21cc gas trimmer making it a gas replacement” (Source 3). Gas tools are outside this post, so that comparison is not used.

This trimmer is in the post because its listing states the battery platform, the runtime claim, the weight, the speed and what is not in the box. Its 40V platform differs from the RAXONE’s 21V platform, so the two picks cover two battery systems.

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RAXONE 21V 2-in-1 string trimmer and edger

The listing says the package includes two 2.5Ah batteries and a fast charger, so this is not a tool-only item. Tool-only flag: no. Its title leads with string trimming, which is why it sits in this section and not with the edger. The listing also says the head rotates 90 degrees to switch from trimming to edging and tilts from 0 to 90 degrees.

The listing gives a 12 inch cutting width, a weight of 6.2 pounds and a speed of 9500 rpm. It says the trimmer has an automatic line feed and includes 10 lines. It does not state runtime or charge time, and it does not say whether these 21V batteries work with any other tool. Those gaps matter if you already own a battery system.

Automatic line feed matters for safety. The Virginia Tech guide warns that automatic-feed trimmers can release more string than needed, which is why the safety section includes a line-length check. For another cordless trimmer on this site, see Black and Decker 20V cordless weed eater.

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Edger picks

The pool labelled three items as edgers. One is a dedicated edger and is picked below. One is a multi-head brush cutter with blade heads and is left out. The third is the RAXONE 2-in-1, which is covered above with the string trimmers. The edger side therefore has one pick, not two.

worksky 9 inch lawn edger, tool only

The listing describes a wheeled edger with a 9 inch steel blade and three depth settings that run from 1.3 to 1.75 inches. It gives a 1.77 inch front wheel and a 4 inch rear wheel, and says a plough blade makes a wider groove in one pass. The listing gives a weight of 7.2 pounds, a speed of 3500 rpm and an 800w motor. It describes a safety lock and a dual-action start that prevent accidental activation. The listing field gives a 3 year warranty.

Tool-only flag: yes. The listing says it has no battery and charger, and also claims compatibility with a Milwaukee 18V battery. That is a claim in the listing text. No Milwaukee page was opened for this post, so it is not confirmed here.

This edger is in the post because it is the only dedicated edger in the pool. Its listing states the blade size, the depth settings and the wheel layout that the edging job depends on. Its steel blade is also why the safety section includes the rule about metal blades.

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Safety for string trimmers and edgers

These rules apply to the three picks. Virginia Tech’s guides cover gas models too. Gas-powered trimmers and edgers are outside this post, so only the general statements from the guides are used here.

  • Eye and ear protection. Virginia Tech’s guide says to “Wear full eye and ear protective devices when operating powered hand tools” (Source 2). The guide cites a past study on trimmers and edgers and reports that “About one-third of these cases are eye injuries” (Source 2). Black+Decker’s guide says to “always wear close-toed shoes or sneakers, long pants, and safety glasses or goggles to protect your eyes” (Source 4).
  • Thrown objects. “String trimmers are known to throw stones, sticks, and other objects at high speeds” (Source 1). Worx’s support page, for a 6 AMP electric model, adds this edging caution: “Take extra caution while edging as objects can be thrown from the trimmer line” (Source 6).
  • Head height and footing. “Maintain balance and firm footing. Avoid over-reaching and always keep the string head below waist level.” (Source 1)
  • Auto-feed string length. The RAXONE listing describes an automatic line feed. The guide says to “Check the trimmer string length periodically” and warns that “Automatic-feed and bump-feed trimmers may release more string than needed” (Source 1). It adds that this “increases the chances of striking the operator” (Source 1). For line questions on a Ryobi weed eater, see Ryobi One Plus weed eater string.
  • Edger blade and guards. “Make sure the edger blade is firmly attached and rotates freely” (Source 2). “Do not operate a lawn edger without protective guards or shields in place” (Source 1).
  • Edger start and service. “Do not start an edger with the blade in contact with the ground so as to avoid uncontrolled movement and possible injuries” (Source 1). “Do not inspect, repair, or carry out maintenance work on a lawn edger with its power unit running” (Source 1).
  • Surfaces and metal blades. “Do not use a lawn edger on gravel surfaces” (Source 1). The worksky edger has a steel blade, and the guide says “Lawn edgers with metal blades are capable of cutting through underground objects, splintering concrete, and causing sparks” (Source 1).
  • Battery before line work. Black+Decker’s support guide gives this step for its own cordless trimmer: “Unplug the trimmer or if cordless, remove the battery” (Source 5). The sources we opened do not give a line-change or blade-change step for the Ryobi, RAXONE or worksky models, so check each manual before you touch the line or the blade.
  • Charging and storage. None of the listings states charging or storage steps. Use the manual that comes with the battery and charger for those steps.

How we chose

The criteria were three. An item had to match the tool type for its side. Its own listing had to state enough figures to describe the tool. Any battery claim is reported as the listing states it and is not confirmed where no manufacturer page was opened. The scan returned six products, three labelled string trimmers and three labelled edgers. Three are in this post: two string trimmers and one dedicated edger.

Left out. The EGO STA1600 16 inch string trimmer attachment is a head, not a complete trimmer. Its listing says it works with EGO power heads PH1400 and PH1420, which are sold separately, and no power head is in the pool. The Houselife 12 inch weed wacker is tool-only, and its battery claim is for Milwaukee M18 batteries, which only the listing text states. Its dimensions field reads 1 inch by 1 inch, which does not match the 12 inch cutting width given elsewhere in the same listing, so this post does not use its figures. The ALSO GO 24V unit is labelled an edger, but its bullets describe a multi-head brush cutter with metal, saw and plastic blades for thick weeds, small branches and soft lawn grass. It is not a dedicated edger, so it is not an edger pick.

The RAXONE is labelled an edger in the pool. Its title and bullets lead with string trimming, and its edging step is a head rotation on the same tool, so it is placed with the string trimmers.

Dates. The scan date in the listing data is 2026-10-29. Individual items carry dates from 2026-10-12 to 2026-10-29, so a listing may have changed since its item date. The six sources were opened on 2026-10-30, and each appears in the source list below.

The picks are a choice from a small pool, not a ranking. This post does not claim that one tool is better overall.

What we could not verify

  • Battery fit for the worksky edger. The listing says it is compatible with a Milwaukee 18V battery, and no Milwaukee page was opened.
  • Which cutting width is right for the Ryobi trimmer. The title says 15 inch and the cutting width field says 13 inches.
  • Whether the Ryobi model is still sold. The Ryobi page marks it Discontinued, and the listing data here does not show current stock.
  • The warranty term for the Ryobi model. The listing field says 30 Day Limited Warranty. The Ryobi page links to its warranty information without giving a term for this model.
  • Runtime, charge time and tool compatibility for the RAXONE and worksky models. The listings do not state them.
  • Whether the RAXONE batteries work with any other tool. The listing does not say.

What the sources do not say

  • How an edge cut by a string trimmer compares with one from a dedicated edger for straightness or finish. None of the sources we opened compare the two.
  • How to set the depth or angle on the RAXONE head or the worksky wheels beyond what each listing states. Black+Decker’s guide describes the head flip for combination trimmers and edgers in general, and gives no steps for the models in this post.
  • Blade-change or blade-removal steps for a cordless edger. None of the sources we opened gives those steps for the worksky or any other pick.
  • Charging, storage or battery life steps for any pick. Black+Decker’s support page covers that battery step for its own auto-feed trimmer only.
  • Whether the Worx page applies to a cordless model. It covers a 6 AMP electric model, so only its general edging caution is used.

Buying checklist

  • Confirm whether the battery and charger are in the box. For the Ryobi bare tool and the worksky edger, they are not.
  • Confirm the battery platform before you buy a tool-only model. Treat the worksky battery claim as the listing’s claim until the battery maker confirms it.
  • Read the title and the cutting width field together. For the Ryobi trimmer, they disagree.
  • Check the status of the model on the manufacturer page. The Ryobi page marks its model Discontinued.
  • For an edger, check that the blade is firmly attached and rotates freely before first use.
  • For an auto-feed trimmer, check the string length periodically.
  • If the battery platform matters most, compare another cordless trimmer on this site: DeWalt 20V Max brushless weed eater.

Mistakes to avoid

  • Expecting a battery in the Ryobi bare-tool box. Its listing says Battery and Charger Sold Separately.
  • Using a lawn edger on gravel. The guide says not to use a lawn edger on gravel surfaces.
  • Using a string trimmer for anything other than weeds and grass. The guide says to use it only for trimming weeds and grass.
  • Treating the worksky battery fit as confirmed. The listing states it, and this post does not confirm it.

FAQ

Is a string trimmer or an edger the better buy for lawn edges?

Neither is better overall. An edger matches a cut along a paved edge, and a string trimmer matches grass and weed work around posts, trees and fences. If the edge you need runs along a walk, drive or patio, an edger is the closer match.

Can one string trimmer do both jobs?

Some combination models do both. Black+Decker’s guide describes flipping the head to vertical for wheeled edging, and the RAXONE listing describes rotating its head 90 degrees to edge. The sources we opened do not say how that edge compares with a dedicated edger.

Does the Ryobi trimmer come with a battery?

No, the listing says the battery and charger are sold separately. The Ryobi page lists a Tool Only option and an option with one 4Ah battery and charger, and it marks the model Discontinued.

Will the worksky edger work with a Milwaukee 18V battery?

The listing says it is compatible with a Milwaukee 18V battery and includes no battery or charger. The sources we opened do not cover Milwaukee battery fit, so confirm it with the battery maker before you buy.

What eye protection should I wear with either tool?

Virginia Tech’s guide calls for full eye and ear protection with powered hand tools. Black+Decker’s guide adds long pants, closed-toe shoes or sneakers, and safety glasses or goggles.

Bottom line

Choose by the job at the edge. Grass and weeds around fixed objects point to a string trimmer, and a cut along a paved edge points to an edger. If one battery tool has to do both, check whether its battery and charger are in the box before you buy.

Sources

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