How long does it take to grind a stump? That depends on more than just the size. If you've ever tackled one yourself or watched a pro do it, you already know-stump grinding is part science, part experience. In this guide, we break down average time estimates by stump diameter, along with what actually affects those timelines in real-world conditions.
Whether you're renting a grinder, hiring help, or managing jobs for clients, this table will give you a realistic idea of what to expect.
Budgeting for stump work? See our Stump Grinding Cost Estimator by Diameter & Location (2025) to get a clear idea of expenses based on size.
Key Takeaways
- Larger stumps take exponentially more time-grinding a 24" stump can take 2-3× longer than a 12".
- Soil conditions, tree species, and root depth can double or triple your time.
- Expect to reposition the grinder for anything over 15", especially on hardwoods.
- 25+ HP machines are best for stumps 24"+ or in tough soil.
Average Stump Grinding Time by Diameter
The table below estimates how long it typically takes to grind a stump based on its diameter, under average conditions (dry soil, common species). It also includes extended time ranges for tougher scenarios-like hardwoods, clay soil, or high-cut stumps.
| Stump Diameter | Estimated Time (Dry Soil, Avg Species) | Time Range (Hardwood / Difficult Conditions) | Notes 🪵 |
|---|---|---|---|
| 6 inches | 5–10 minutes | 10–15 minutes | Fastest jobs; shallow roots, low stump = quick pass |
| 8 inches | 8–15 minutes | 15–25 minutes | Still light work for sharp teeth + dry ground |
| 10 inches | 10–20 minutes | 20–30 minutes | Most common residential size; soil matters |
| 12 inches | 15–25 minutes | 30–45 minutes | Time can double for hardwoods or high-cut stumps |
| 15 inches | 20–30 minutes | 45–60 minutes | Bigger root zone; operator skill makes a big difference |
| 18 inches | 30–45 minutes | 60–75 minutes | Often requires repositioning grinder multiple times |
| 20 inches | 45–60 minutes | 75–90 minutes | Confirmed by multiple sources (avg: 1–2 hrs) |
| 24 inches | 60–90 minutes | 90–120 minutes | May require two passes or commercial-grade equipment |
| 30 inches | 1.5–2 hours | 2–3 hours | Common size for mature trees; multiple root flares likely |
| 36+ inches | 2–3 hours | 3–5+ hours | Best handled with 25+ HP or professional crew |
| 48+ inches | 3-4+ hours | 4–6+ hours | Requires pro-grade or tracked grinder for efficiency |
What This Table Shows
This table compares stump diameter (in inches) with:
- Estimated grinding time under average conditions (dry soil, non-hardwood)
- Extended time ranges if the stump is hardwood, high-cut, or in tough soil
- Practical notes on grinder repositioning, depth, and difficulty
It's not just about the diameter-soil type, stump height, and tree species can easily double the time. For instance, a 12" pine stump in sandy soil may take 20 minutes, while a 12" oak in clay could push 45+ minutes.
How to Use This Data in Real Life
1. Choose the Right Grinder for the Job
- Under 15" stumps? A 8-14 HP walk-behind unit works fine.
- Over 24" or in compacted soil? You'll want at least 20+ HP, preferably tracked.
- Multiple stumps or commercial work? Time adds up fast. Opt for a high-torque hydraulic grinder with depth control.
2. Set Realistic Expectations
Don't fall into the trap of thinking "it's just one stump." A 30"+ hardwood stump can take 2-3 hours, especially if you're repositioning a smaller machine every 10 minutes.
If you're billing clients or planning a rental day, this info helps you:
- Quote more accurately
- Avoid underestimating time and fuel use
- Plan breaks, refuels, or grinder repositioning
3. Prepare Your Site to Save Time
- Cut the stump as low as possible before grinding-it can shave 20-30% off your time.
- Clear debris and rocks from around the stump to prevent damage and slowdowns.
- Water the ground a day before if soil is extremely dry and dusty-it helps with visibility and cuts down airborne grit.
Final Thoughts
Stump grinding isn't just a question of machine power-it's about prep, conditions, and choosing the right tool for the job. This table gives you a clear benchmark for how long it really takes, so you can go in prepared, stay efficient, and avoid nasty surprises.
Once the stump is ground, learn how to reclaim your yard in our What to Do After Grinding a Stump: Your Complete Guide for tips on cleanup and reuse.
Looking for a grinder that can handle 12"+ stumps without breaking a sweat?
👉 Check out our stump grinders here →
