LED PSU Calculator

Configure your LEDs and find the perfect power supply

Configure Your LEDs

Add your LED strips or matrices and specify their parameters

5V

Industry standard - Most popular

18.0 W/m
Strip Power Draw36.0W
Power Required
5V
14W
2PSUs are a good fit for 14W

Matching Power Supplies

14W•5V
Best MatchProfessional
Mean Well RS-15-5

Mean Well RS-15-5

15W•5V•★★★★
Perfect fit

Ultra-compact industrial quality for very small 5V projects

Amazon →AliExpress →
Professional
Mean Well RS-25-5

Mean Well RS-25-5

25W•5V•★★★★
Ample capacity

Compact industrial quality for small 5V projects

Amazon →AliExpress →
Professional
Mean Well LRS-50-5

Mean Well LRS-50-5

50W•5V•★★★★
High capacity

Industrial quality for small projects, 86% efficiency, UL certified, 3-year warranty

Amazon →AliExpress →
Professional
Mean Well LPV-100-5 (IP67)

Mean Well LPV-100-5 (IP67)

60W•5V•★★★★
High capacity

IP67 waterproof rated, outdoor-ready industrial quality

Amazon →AliExpress →
Professional
Mean Well LRS-75-5

Mean Well LRS-75-5

70W•5V•★★★★
High capacity

Industrial quality, 87% efficiency, UL certified, 3-year warranty, best value Mean Well for small-medium projects

Amazon →AliExpress →

Quick Reference Tables

These tables show typical power consumption for common LED strip types. Keep in mind that actual values vary by manufacturer, so always check your specific product's datasheet when available.

LED Strip Power Consumption by Type

LED TypeVoltagePower per MeterTypical Use
WS2812B RGB (30 LEDs/m)5V9W/mBudget option for accents
WS2812B RGB (60 LEDs/m)5V18W/mIndustry standard - Most popular
WS2812B RGB (144 LEDs/m)5V43.2W/mHigh density for detailed work
SK6812 RGB (30 LEDs/m)5V9W/mBudget alternative to WS2812B
SK6812 RGB (60 LEDs/m)5V18W/mAlternative to WS2812B
SK6812 RGB (144 LEDs/m)5V43.2W/mHigh density alternative
WS2813 RGB (30 LEDs/m)5V9W/mBackup data line, fault tolerant
WS2813 RGB (60 LEDs/m)5V18W/mBackup data line, reliable
SK9822/APA102 RGB (60 LEDs/m)5V18W/mClock+Data, fast refresh, POV
SK9822/APA102 RGB (144 LEDs/m)5V43.2W/mHigh density clock+data
WS2812B-mini 2020 (60 LEDs/m)5V12W/mCompact 2x2mm package
SK6812 RGBW (30 LEDs/m)5V9W/mWhite channel for accents
SK6812 RGBW (60 LEDs/m)5V18W/mPopular for indoor lighting
SK6812 RGBW (144 LEDs/m)5V43.2W/mHigh density with white
WS2815 RGB (30 LEDs/m)12V9W/m12V dual-signal, longer runs
WS2815 RGB (60 LEDs/m)12V18W/m12V dual-signal, most popular
WS2815 RGB (144 LEDs/m)12V43.2W/m12V high density
WS2811 RGB (30 LEDs/m)12V9W/m3-LED segments, outdoor use
WS2811 RGB (60 LEDs/m)12V18W/m3-LED segments, general use
GS8208 RGB (30 LEDs/m)12V9W/m12-bit gamma, dual data signal
GS8208 RGB (60 LEDs/m)12V18W/m12-bit gamma, holiday pixels
TM1814 RGBW (60 LEDs/m)12V18W/m12V RGBW, 3-LED segments
WS2812B FCOB (180 LEDs/m)5V11W/m5V 1 IC per LED, fully addressable
WS2811 FCOB 12V (576 LEDs/m)12V8W/m12V dot-free, segment addressable
WS2811 FCOB 24V (576 LEDs/m)24V16W/m24V dot-free, longer runs
WS2811 FCOB 24V (630 LEDs/m)24V19W/m24V high density, seamless light
WS2811 FCOB 24V (720 LEDs/m)24V21W/m24V highest density, most popular
WS2814 FCOB RGBW (784 LEDs/m)24V21W/m24V RGBW with white channel

Power Supply Derating Guidelines

Heat is the enemy of power supplies. The hotter your environment, the less load your PSU can safely handle, and the shorter it will last. If your setup runs in a warm enclosure or during summer months, plan accordingly.

Operating TempMax Load %Expected Lifespan
25°C (77°F)100%50,000 hours
40°C (104°F)90%40,000 hours
50°C (122°F)80%30,000 hours
60°C (140°F)70%20,000 hours
70°C (158°F)60%10,000 hours

How to Calculate LED Power Supply Requirements

Here's how the calculator figures out what PSU you need. It's a straightforward process once you know the steps.

  1. 1

    Identify LED strip specifications

    Find the power consumption specification from your LED strip manufacturer's datasheet. This is typically listed as watts per meter (W/m) for COB/FCOB strips, or watts per LED for addressable LEDs like WS2812B.

    Example:

    WS2812B draws 0.3W per LED at full white (18W/m at 60 LEDs/m), WS2811 FCOB 24V draws 21 W/m
  2. 2

    Measure total run length

    Measure the total length of LED strips you plan to install, accounting for all segments. For matrix configurations, multiply width by height to get total LED count. If running multiple parallel strips, add their lengths together.

    Example:

    Three 2-meter strips = 6 meters total, or 16×16 matrix = 256 LEDs
  3. 3

    Calculate base wattage

    Multiply power consumption per unit by total length or LED count.

    For continuous LEDs: Base Wattage = (Power per meter) × (Length in meters)

    For addressable LEDs: Base Wattage = (Watts per LED) × (Number of LEDs)

    Example:

    14.4 W/m × 5m = 72W, or 0.3W × 300 LEDs = 90W
  4. 4

    Apply 20% safety factor

    Multiply base wattage by 1.2 to add a 20% safety margin. This prevents the PSU from running at maximum capacity, which causes overheating, reduces lifespan, and doesn't account for voltage drop over distance.

    Formula: Required Wattage = Base Wattage × 1.2

    Example:

    72W × 1.2 = 86.4W required
  5. 5

    Select commercial PSU rating

    Choose the next available commercial power supply rating above your calculated requirement. Power supplies come in standard sizes: 30W, 60W, 100W, 150W, 200W, 300W, etc.

    Important: Verify the voltage matches your LEDs (5V, 12V, 24V, or 48V).

    Example:

    For 86.4W calculated → select a 100W power supply

Complete Worked Example

Let's calculate the power supply requirements for a 5-meter WS2812B RGB LED strip (60 LEDs/m) at 5V:

Step 1: LED Specification

WS2812B at 60 LEDs/m × 0.3W = 18 W/m

Step 2: Total Length

Total strip length = 5 meters (300 LEDs)

Step 3: Base Wattage

18 W/m × 5m = 90W

Step 4: Apply Safety Factor

90W × 1.2 = 108W

Step 5: Select PSU

Next standard size above 108W = 150W power supply

✓ Final Answer: Use a 5V 150W (30A) power supply

Understanding the Power Calculation Formula

The math behind LED power calculations is actually pretty simple. Here's what each part means and why it's there.

Required PSU Wattage = (Power per meter) × (Length in meters) × (Safety Factor)

Power per meter

This varies by LED type. Addressable LEDs like WS2812B use watts per LED (typically 0.3W at full white). Continuous strips like SMD 5050 use watts per meter (typically 14.4W/m for 12V). Always check your specific LED datasheet for accurate values.

Length in meters

Total length of all LED strips in your installation. If running multiple strips in parallel from the same PSU, add up their individual lengths. For matrices, multiply width × height to get total LED count, then use watts per LED instead of watts per meter.

Safety Factor (1.2 = 20%)

Adding 20% prevents the PSU from running at 100% capacity continuously. Benefits: prevents thermal stress and overheating, extends PSU lifespan significantly (heat is the #1 killer of electronics), accounts for voltage drop over wire distance, provides headroom for future expansion, ensures stable voltage under full load. Never operate a PSU at its maximum rated capacity 24/7.

💡 Why This Formula Works

Power (Watts) is the product of voltage and current: P = V × I. When you know how much power your LEDs consume per meter and how many meters you have, you can calculate total power draw.

The 20% safety factor is critical because:

  • Power supplies degrade over time - capacity decreases with age
  • Running at 100% capacity generates excessive heat, reducing lifespan dramatically
  • Wire resistance causes voltage drop, especially over distance
  • Future-proofing: you might add more LEDs or run them brighter later
  • Manufacturing tolerances mean your PSU might not deliver exactly its rated capacity

Professional installations often use 30-40% safety margins for mission-critical applications. The 20% minimum recommended here balances cost and reliability for hobby and semi-professional use.

Formula Variants for Different LED Types

Addressable LEDs (WS2812B, SK6812)

Watts = (LED Count × Watts per LED) × 1.2

Example: 300 LEDs × 0.3W × 1.2 = 108W

Continuous LEDs (COB, FCOB, SMD)

Watts = (Meters × Watts per meter) × 1.2

Example: 8m × 14.4W/m × 1.2 = 138W

Matrix Configuration

Watts = (Width × Height × Watts per LED) × 1.2

Example: 16×16 × 0.3W × 1.2 = 92W

Multiple Strips (Parallel)

Watts = (Total Length × Watts per meter) × 1.2

Example: (3m + 2m + 4m) × 18W/m × 1.2 = 194W

Frequently Asked Questions

Quick answers to common LED power supply questions. Click any question to reveal the answer.

LEDs appear dim at the end due to voltage drop - the electrical resistance of the copper traces causes voltage to decrease over distance. For 5V LEDs, voltage drop becomes noticeable after 3-5 meters.

Solutions:

  • ▸Inject power at multiple points along the strip (beginning, middle, and end for long runs)
  • ▸Use thicker wire gauge (lower AWG number like 16 or 18 AWG)
  • ▸Switch to higher voltage LEDs (12V or 24V) which are less affected by voltage drop
  • ▸Keep individual strip runs under the recommended maximum length for your voltage

An undersized power supply will cause multiple problems:

Immediate symptoms:

  • ▸LEDs appear dim or colors are incorrect (especially white appears yellow/orange)
  • ▸Flickering or intermittent operation
  • ▸Animations run slower than expected
  • ▸Some LEDs don't light up at all

Long-term damage:

  • ▸Power supply runs excessively hot and fails prematurely
  • ▸Thermal shutdown protection activates, cutting power completely
  • ▸Voltage sag damages LED driver circuits
  • ▸Fire hazard in extreme cases

Always size your PSU at least 20% above your calculated maximum draw

to prevent these issues and ensure safe, reliable operation.

A moderately oversized power supply (up to 2-3x your requirement) is perfectly fine and actually beneficial.

Benefits of oversizing:

  • ▸Longer PSU lifespan due to cooler operation (less thermal stress)
  • ▸Room for future expansion without replacing PSU
  • ▸Better efficiency at typical load levels (most PSUs are most efficient at 50-80% load)
  • ▸Reduced electrical noise and ripple
  • ▸More stable voltage under varying loads

When oversizing becomes wasteful:

  • ▸Only excessive oversizing (5x+ your needs) wastes money on upfront cost
  • ▸Very low loads (<10% of PSU capacity) may reduce efficiency slightly
  • ▸Larger physical size may not fit in your enclosure

Sweet spot:

A 100W PSU powering a 60W LED installation is ideal - plenty of headroom without waste.

Connect multiple strips in parallel, never daisy-chain for power:

Correct wiring method:

1. Run separate positive (+) and negative (-) wires from the PSU to each strip's input 2. Use a terminal block or distribution board to split PSU output to multiple strips 3. Never run power through one strip to feed another (daisy-chaining causes voltage drop)

Wire gauge considerations:

  • ▸Calculate total current: sum of all strips
  • ▸Use appropriate wire gauge based on total current and longest distance
  • ▸Thicker wire for longer runs to minimize voltage drop

PSU sizing:

  • ▸Total PSU wattage must cover the sum of ALL strips plus 20% safety margin
  • ▸Example: Three 20W strips = 60W + 20% = 72W minimum PSU

For addressable LEDs:

  • ▸Power in parallel (separate wires to each strip)
  • ▸Data in series (DOUT of strip 1 connects to DIN of strip 2)

Inject power when you notice voltage drop symptoms or exceed recommended lengths:

Inject power when:

  • ▸5V strips exceed 2.5 meters - inject every 2.5m for best results
  • ▸12V strips exceed 5 meters - inject every 5m
  • ▸24V strips exceed 10 meters - inject every 10m
  • ▸You see visible dimming or color shift at the far end
  • ▸Running LEDs at full brightness (worst case for voltage drop)

How to inject power:

1. Connect additional power wires (+/-) to the strip's power pads at the midpoint or end 2. Run these wires back to your PSU (or use a second PSU) 3. Use the same wire gauge as your main power connection 4. Only connect power (+/-), NOT data signal

Pro tip:

For very long runs (10m+), inject power at BOTH the beginning and end of the strip, or every 5 meters for uniform brightness.

Yes, you should use a fuse for any installation over 60W.

Fuses protect against short circuits, wiring faults, and prevent fires.

Fuse sizing rule:

Choose a fuse rated at 125-150% of your expected maximum current.

Examples:

  • ▸60W @ 5V (12A) → 15A fuse
  • ▸100W @ 5V (20A) → 25A fuse
  • ▸150W @ 12V (12.5A) → 15A fuse
  • ▸300W @ 12V (25A) → 30A fuse

Fuse types for LED projects:

  • ▸Automotive blade fuses: Cheap, easy to find, good for DC
  • ▸Inline fuse holders: Mount on your positive wire between PSU and LEDs
  • ▸Resettable fuses (polyfuses): Auto-reset after cooling

Important notes:

  • ▸Fuse goes on the positive wire only
  • ▸Place fuse as close to PSU as practical
  • ▸A blown fuse indicates a problem to diagnose

About

Why this exists.

Figuring out which power supply you need for an LED strip project involves a bunch of calculations. This tool does that math for you and shows matching products.

The recommendations default to Mean Well because they have proper certifications, low failure rates, and cost about the same as generic alternatives.

20+LED presets
43PSUs
5–48VRange