🔍 ID GUIDE

Millipede vs. Centipede — Fast ID

Both are multi-legged arthropods but one is beneficial and one is harmless. Here's the fast ID.

🐛
Centipede
One leg pair per segment; fast; predator
VS
🐛
Millipede
Two leg pairs per segment; slow; decomposer

🔑 Key Difference

Count legs per body segment under magnification: ONE pair per segment = centipede (fast, predator — beneficial). TWO pairs per segment = millipede (slow, eats plant debris — harmless). Centipedes flatten side-to-side; millipedes are cylindrical.

⚠️ Urgency

Both indicate moisture near the foundation. Centipedes are beneficial predators. Millipedes are harmless detritivores. Neither requires urgent treatment — address moisture for both.

📷 Still Unsure?

📷 Photo ID Tool

📊 Full Comparison: Millipede vs. Centipede

FeatureMillipedeCentipede
Legs per segment2 pairs (4 legs)1 pair (2 legs)
SpeedSlow-movingFast-moving
BodyCylindrical, roundedFlattened
Bite riskNone — harmlessCan bite (house centipede: minor pinch)
DietDead organic matter, plant materialPredator — eats insects and spiders
Meaning for your homeMoisture problem or organic matter buildupOther pest activity (centipedes eat them)

🔧 Treatment Guide

Millipedes indicate moisture and organic matter — address the moisture source. Centipedes indicate other pest activity they're feeding on. Neither requires pesticide treatment as a primary control; both are controlled by eliminating their food source and reducing moisture.

💡 Confirm before treating: Misidentification is common with these two species. Capture a specimen and compare against the table above before purchasing any products.

❓ Identification FAQ

Do centipedes bite and is it dangerous?
House centipedes can bite if handled but rarely do. The bite causes minor local pain similar to a bee sting and resolves quickly. No first aid beyond cleaning the area is typically required. Larger outdoor centipedes are more capable of biting.
Why do I suddenly have millipedes everywhere?
Millipede invasions typically follow heavy rain — they're driven out of saturated soil. Improve drainage around your foundation and seal entry points. A perimeter spray with bifenthrin will deter them, but addressing the moisture issue is the permanent solution.
What's the fastest way to confirm which pest I have?
Capture a live or dead specimen and compare it directly against the identification features in this guide. A clear close-up photo submitted to your county's cooperative extension service will get you a free expert identification within 1–3 business days. iNaturalist is also excellent for invertebrate ID.
Can I treat for both at the same time?
If you're unsure which pest you have, it's often more effective to wait for confirmation rather than applying multiple treatments. Misapplied pesticides can scatter populations without eliminating them. The exception: if both pests require identical treatment (as with many fall invaders), treating once covers both.

📚 More on This Topic

Related guides and profiles:

🔗 🐛 Centipede vs. Millipede🔗 🐛 House Centipede🔗 🐛 House Centipede — Complete Guide
Published: Jan 1, 2025 · Updated: Apr 7, 2026