A string trimmer is a handheld yard tool that uses a rapidly spinning nylon line instead of a metal blade to cut grass and weeds in spots a lawn mower cannot reach.
If you have ever struggled to shear the grass snuggling a fence, a tree trunk, a mailbox post, or the edge of a driveway, you have found the exact job a string trimmer solves. It is also called a weed eater, weed whacker, whipper snipper, or strimmer, but the mechanism is the same: a spinning head flings strands of plastic line fast enough to sever stems. The line is lightweight, flexible, and replacement spools cost only a few dollars. What makes the tool indispensable is its ability to cut flat against vertical surfaces and square off lawn edges without damaging the mower or the landscaping.
How a String Trimmer Works and Who Should Use One
A string trimmer cuts with a rotating monofilament line rather than a steel blade, which makes it safe enough to use near hardscaping and young trees but still powerful enough for most woven weeds. The line wears down during use; many models advance fresh line automatically, and others use a bump-feed mechanism—tap the head on the ground and more line feeds out. Cutting with it is close to sweeping: keep the head two to three inches above the ground and move the tool side to side in steady passes. Tilt the head 90 degrees and the spinning line becomes an edger that cleans up the crisp boundary between grass and pavement.
Households with a quarter-acre or more nearly always own one. For lawns up to half an acre, a 20- to 40-volt-max battery model or a corded electric trimmer gets the job done. For properties between half an acre and one acre, a 40- to 80-volt-max battery unit or a gas-powered trimmer provides more runtime and power. Above one acre, gas trimmers are the standard because they run as long as the fuel lasts and handle heavier growth.
Power Source Options and What They Cost
Battery trimmers are the most popular choice today because they start instantly, weigh less than gas models, and need no fuel mixing. The trade-off is runtime: a typical 20-volt battery trims for about 20 to 30 minutes, and larger 40- to 80-volt packs can run for 45 to 60 minutes. Replacement batteries add $50 to $100 to the total cost. Corded electric trimmers are the cheapest option—many sell for under $60—but they require a 50- to 100-foot extension cord and lose convenience the farther you are from an outlet. Gas string trimmers offer unlimited runtime and the most torque for thick weeds and overgrown lots, but they are heavier, noisier, and require two-stroke oil mixing and seasonal maintenance.
Wirecutter’s testing found the best string trimmers land between $200 and $300. Consumer Reports reports a wider range of $95 to $350 overall, with smaller 20-volt models falling between $100 and $200. The price you pay depends mostly on the power source and whether the trimmer includes a battery and charger. A reader shopping for a solid all-rounder should read our tested roundup of the best handheld string trimmers for homeowners, which compares battery life, cut quality, and value across the current market.
| Power Source | Best Lawn Size | Typical Price Range |
|---|---|---|
| 20–40V battery | Up to ½ acre | $100 – $200 |
| 40–80V battery | ½ to 1 acre | $200 – $300 |
| Corded electric | Any (within cord reach) | $30 – $80 |
| Gas (2-stroke) | Over 1 acre | $150 – $350 |
Three Common Mistakes That Ruin a Good Trim Job
Wrong line diameter. The line size must match the power output of the trimmer. A light-duty electric trimmer spooled with thick.095-inch line will struggle to feed and may bog down. Heavy-duty gas trimmers need.080-inch or larger line to cut brush; using thin.065-inch line on them wastes the tool’s power. Check the owner’s manual and buy the diameter it specifies. Holding the head too low or too high. Keeping the head two to three inches off the ground produces a clean cut. Any lower scalps the turf; any higher leaves ragged grass behind. Using a string trimmer on thick brush. String trimmers are for grass and light weeds. Dense brush, saplings, and overgrown shrubs require a metal-blade brush cutter. Pushing nylon line through woody stems overheats the head, snaps the line repeatedly, and risks debris hitting the user or bystanders.
FAQs
Can a string trimmer replace a lawn mower?
No. String trimmers excel at detail work—edges, corners, obstructions—but they cut slower than a mower and leave an uneven surface on open lawn. A mower handles the main area; a trimmer finishes what the mower misses.
How often should I replace the cutting line?
Every time you trim, the line wears shorter. Replace or advance the line when it no longer reaches four to six inches from the head. Running on very short line forces you to lower the head, which increases the risk of scalping the grass.
Are battery trimmers as powerful as gas ones?
Not yet. A top-tier 80-volt battery trimmer cuts through typical lawn weeds and grasses with the same speed as a gas trimmer, but gas still has an edge on heavy overgrowth and continuous runtime. For weekly trimming on a standard lot, a quality battery model is more convenient and quieter.
References & Sources
- Wikipedia. “String Trimmer.” Overview of tool types, naming, and basic operation.
- Consumer Reports. “String Trimmer Buying Guide.” Price ranges, corded-model extension cord requirements, and selection advice.
- Wirecutter (The New York Times). “The Best String Trimmer.” Testing-based best-model price range and performance comparisons.