I’ve used both for years. And here’s the truth—it all comes down to one thing: comfort or power.
These trimmers are strong. They run on battery but work like gas. You won’t miss your old gas tool.
But here’s the deal—once you trim for 30 minutes, feel matters more than specs.
I’ve trimmed in spring, edged in summer, and cleaned up in fall. I’ve faced thick weeds, crabgrass, and tight flower beds. My yard throws it all at me.
After years of hands-on use, I know what works. I’ll help you pick the one that fits you.
Table of Contents
Detailed Comparison — EGO ST1511T vs ST1521S
I’ve used both the EGO ST1511T and ST1521S for all kinds of trimming—from sidewalk edges to thick weeds. While they look similar, they feel very different. Let’s break down the key features to help you choose the right one.
Blade Length: EGO ST1511T vs ST1521S
Both trimmers have a 15-inch cutting swath. That’s wide enough for most yards. But the ST1521S sometimes leaves a tighter cut, likely due to the head shape.
Feature | ST1511T | ST1521S |
Cutting Width | 15 inches | 15 inches (feels like 14″) |
Line Type | Dual-feed, spiral 0.095″ | Dual-feed, spiral 0.095″ |
Swath Feel | Wide and smooth | Tight and precise |
Rating:
ST1511T: 9/10
ST1521S: 8.5/10
Cutting Power: EGO ST1511T vs ST1521S
Both use the same brushless motor and chew through weeds with ease. But the ST1521S feels more firm in tough spots.
Feature | ST1511T | ST1521S |
Motor | Brushless | Brushless |
Speeds | 2-speed switch + trigger | Single-speed variable |
Power Feel | Strong with control | Strong and steady |
Rating:
ST1511T: 9/10
ST1521S: 9.5/10
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Battery Life: EGO ST1511T vs ST1521S
Both come with a 2.5Ah battery. But the ST1511T’s low-speed mode gives it the edge on light jobs.
Feature | ST1511T | ST1521S |
Battery | 56V 2.5Ah | 56V 2.5Ah |
Run Time | Up to 45 mins (low speed) | 30–40 mins |
Efficiency | High on low speed | Less control over drain |
Rating:
ST1511T: 9.5/10
ST1521S: 8.5/10
Handle Comfort and Grip: EGO ST1511T vs ST1521S
This is where the ST1511T shines. It fits better and adjusts fast.
Feature | ST1511T | ST1521S |
Handle | Tool-free adjustable | Fixed (needs a screwdriver) |
Shaft | Telescopic aluminum | Fixed carbon fiber |
Fit for Height | Easy to adjust | One-size-fits-most |
Rating:
ST1511T: 10/10
ST1521S: 8/10
Weight and Balance: EGO ST1511T vs ST1521S
They’re both under 8 lbs, but the balance makes a big difference.
Feature | ST1511T | ST1521S |
Weight | 7.63 lbs | 7.28 lbs |
Battery | Included (2.5Ah) | Included (2.5Ah) |
Balance | Easy to adjust | Heavier feel during use |
Rating:
ST1511T: 9/10
ST1521S: 8/10
Noise Level: EGO ST1511T vs ST1521S
Both are quieter than gas trimmers. But one has a softer tone.
Feature | ST1511T | ST1521S |
Noise Level | ~70 dB | ~70 dB |
Sound | Softer on low speed | Louder at full power |
Rating:
ST1511T: 9.5/10
ST1521S: 8.5/10
Ease of Use: EGO ST1511T vs ST1521S
Both trimmers are easy to set up and load line. But one is more flexible.
Feature | ST1511T | ST1521S |
Line Loading | POWERLOAD | POWERLOAD |
Adjustable Shaft | Yes | No |
Setup | Minimal | Minimal |
Rating:
ST1511T: 10/10
ST1521S: 8/10
Value for Money: EGO ST1511T vs ST1521S
The price difference is small, but the features guide your choice.
Feature | ST1511T | ST1521S |
Price (Kit) | $199–$219 | $229–$249 |
Warranty | 5 years | 5 years + lifetime shaft |
Extras | Telescopic shaft | Carbon fiber shaft |
Rating:
ST1511T: 9.5/10
ST1521S: 9/10
Final Verdict: EGO ST1511T vs ST1521S
Both are strong tools. It depends on what you care about most.
Category | ST1511T | ST1521S |
Best For | Comfort and fit | Durability and power |
Runtime | Longer | Good, but less efficient |
Long-Term Perks | 5-year warranty | Lifetime shaft + 5-year tool |
Overall Rating:
ST1511T: 9.5/10
ST1521S: 9/10
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Handle Comfort vs. Cutting Power: What Matters More?
Over the years, I’ve learned this the hard way—comfort lasts longer than power. When you trim for more than 20 minutes, it shows. The ST1521S is tough. I like the carbon shaft. It’s strong and doesn’t bend. It feels like pro gear. But after edging the full length of my driveway, my shoulders start to feel it. That weight doesn’t move, and it adds up.
The ST1511T feels lighter. It may not be built like a tank, but it fits me better. I drop the shaft low when I edge, then lift it up a bit to trim around trees. That little change helps more than you’d think. After one long spring cleanup last year, my back felt fine the next day. I give credit to that adjustable shaft.
When you use a tool each week, year after year, comfort starts to win. Power fades. But ease stays.
Tips for Getting the Best Results
- Keep a backup spool of 0.095″ line on hand—don’t wait until you run out mid-job.
- Use low-speed mode (ST1511T) when trimming around flower beds, mulch, or garden edges.
- Retract the shaft on the ST1511T before storing—it saves space in sheds or garages.
- Invest in a padded shoulder strap. Even though both trimmers are under 8 lbs, it helps with long trimming sessions.
- If you’re in a suburban area in the U.S., quiet operation matters. Early-morning use won’t wake the neighborhood.
Read More: STIHL vs Husqvarna Trimmer
Final Thoughts on EGO ST1511T vs ST1521S
If comfort, ease, and shared use matter most, go with the ST1511T. It’s the trimmer that works with you. I’ve used it for years, and the back relief is real—especially during spring and fall cleanups when the work piles up.
But if you want pure strength, the ST1521S is built like a tank. It feels solid in your hands, no matter the job. That carbon shaft doesn’t flex, and the lifetime warranty is a big plus. I know folks who use it all year round—and it holds up.
No matter which one you choose, both give you the same power as gas—without the noise or mess. Your lawn will look great. And you won’t waste weekends fixing pull cords or breathing in fumes.
That’s worth a lot. I’ve lived it.
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FAQs: EGO ST1511T vs ST1521S
What’s the key difference between the EGO ST1511T and ST1521S?
The ST1511T has an adjustable shaft for comfort. The ST1521S has a fixed carbon shaft built for strength.
Which trimmer has longer battery life—ST1511T or ST1521S?
The ST1511T lasts longer on low speed. The ST1521S drains faster at full power.
Is the ST1511T or ST1521S better for tall or short users?
The ST1511T works better for all heights. You can adjust the shaft to fit. The ST1521S is best for average height since it doesn’t adjust.
Does the POWERLOAD feature work the same on both models?
Yes. Both use EGO’s POWERLOAD head. Push a button and the line loads by itself.
Which is more comfortable for long trimming jobs—ST1511T or ST1521S?
The ST1511T is easier on your arms. Its adjustable fit helps reduce strain. The ST1521S feels heavier over time.