Strip Length (meters):
Power per Meter (W/m):
Voltage (V):
Safety Margin:
Total Power: 72.00 W
Current Draw: 6.00 A
Recommended PSU: 86.40 W
Daily Consumption (24h): 1.73 kWh
| Strip Type | LEDs/m | W/m | Voltage | Lumen/m |
|---|---|---|---|---|
| SMD 3528 | 60 | 4.8 W | 12V | 360 lm |
| SMD 5050 | 60 | 14.4 W | 12V | 1080 lm |
| SMD 2835 | 120 | 9.6 W | 12V/24V | 960 lm |
| SMD 5630 | 60 | 18 W | 12V | 1800 lm |
| COB Strip | 320+ | 10 W | 24V | 900 lm |
| RGB 5050 | 60 | 14.4 W | 12V | 700 lm |
| RGBW 5050 | 60 | 19.2 W | 24V | 1200 lm |
| WS2812B | 60 | 18 W | 5V | 800 lm |
LED Strip Power Calculator: Size Your Driver Right the First Time
Last month I helped a client rewire a kitchen where a 5-meter LED strip kept flickering after 20 minutes. The issue wasn’t the strip — it was a 24W driver trying to power a 36W load. An LED Strip Power Calculator would have caught that mismatch in seconds.
What It Is & Why It Matters
An LED strip power calculator estimates total wattage by multiplying the strip’s watts-per-meter (W/m) rating by its length, then adds a safety margin for the driver (PSU). Undersized drivers overheat, shortening LED life by up to 50% — a failure mode documented in IES LM-80 lumen-maintenance testing. Oversized drivers waste money and space. Getting this right protects your fixtures, wiring, and warranty.
How to Calculate LED Strip Power
The formula is simple:
Total Watts = W/m × Length (m) × 1.2 (20% safety margin)
Current (A) = Total Watts ÷ Voltage (12V or 24V)
Real example: A 5m SMD 5050 strip rated at 14.4 W/m running at 24V:
14.4 × 5 = 72W → 72 × 1.2 = 86.4W driver minimum → Current = 86.4 ÷ 24 = 3.6A. I’d spec a 96W / 4A driver to stay comfortably under 90% load — the sweet spot for driver longevity.
What Most Guides Get Wrong
Here’s the industry detail few blogs mention: voltage drop. On 12V strips longer than 5m, end-of-run brightness can drop 15–25% because copper traces are thinner than most people assume (typically 2oz Cu on budget strips vs. 3oz on premium). In my testing with a Fluke 87V multimeter, a 10m budget 12V strip measured 10.4V at the far end — dim and color-shifted.
Common misconception: “24V strips use more power.” False. A 24V and 12V strip at 14.4 W/m draw identical wattage — but 24V halves the amperage, cutting voltage drop by ~75%. That’s why commercial installs almost always specify 24V or 48V per NEC Article 411 low-voltage lighting guidelines.
Pro Tips From the Field
✅ Always add 20% headroom — drivers running >90% capacity fail 3–5× faster (per Mean Well thermal data).
✅ Feed power from both ends on strips over 5m to eliminate voltage drop without upsizing wire.
✅ Match dimmer type to driver — TRIAC dimmers need TRIAC-compatible drivers; PWM strips need constant-voltage 0-10V or DALI drivers.
Bottom Line
Sizing an LED strip driver takes 10 seconds with the right math — and prevents fires, flicker, and dead LEDs. Use the calculator above to enter your strip’s W/m, length, and voltage for an instant driver recommendation.
Frequently Asked Questions
How do I calculate LED strip wattage per meter?
Check the datasheet or multiply LED count per meter by each chip’s wattage. Example: 60 SMD 5050 LEDs/m × 0.24W = 14.4 W/m.
Can I run two LED strips off one power supply?
Yes, if their combined wattage plus 20% margin stays under the driver’s rated output and voltages match exactly (both 12V or both 24V).
What size power supply do I need for a 10-meter LED strip?
For a 14.4 W/m strip: 10 × 14.4 × 1.2 = 172.8W. Choose a 200W driver at matching voltage (12V or 24V).
Why is my LED strip dim at the far end?
Voltage drop. Switch to 24V, feed power from both ends, or use thicker gauge wire (14 AWG for runs over 3m).
Is 12V or 24V better for LED strips?
24V is better for runs longer than 5 meters — less voltage drop, thinner wire, cooler drivers. 12V is fine for short accent lighting under 5m.
Last Updated on July 19, 2026 by Kevin Chen
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