Heatsink Calculator

Calculate heatsink thermal resistance and cooling requirements for electronic components instantly. Our free online heatsink calculator helps engineers estimate required heatsink size and verify thermal design for CPUs, MOSFETs, power electronics, and other heat-generating components.

Key Features

✓Calculate required thermal resistance (θ = ΔT / P)
✓Verify junction temperature with existing heatsinks
✓Safety status analysis (Safe, Warning, Critical)
✓Cooling type recommendations (Passive, Active, Liquid)
✓Component-specific presets (CPU, MOSFET, LED, etc.)
✓Step-by-step thermal calculations

Applications

•CPU and processor cooling design
•Power MOSFET thermal management
•LED driver and lighting thermal design
•Voltage regulator cooling requirements
•Power amplifier thermal analysis
•PCB thermal design and component placement

Thermal Resistance Formulas

Required Thermal Resistance

θ = ΔT / P where θ is thermal resistance (°C/W), ΔT is temperature difference (°C), and P is power dissipation (W)

Use this formula to determine what thermal resistance your heatsink needs to achieve to keep the component within safe operating temperatures.

Junction Temperature Calculation

Tj = Ta + (P × θ) where Tj is junction temperature, Ta is ambient temperature, P is power, and θ is thermal resistance

Use this formula to verify if an existing heatsink will keep your component within safe temperature limits.

Cooling Type Guidelines

🌡️ Passive Cooling

Power < 50W, θ > 2°C/W

Natural convection heatsinks, no fans required. Suitable for low-power applications.

🌀 Active Cooling

Power 50-100W, θ 0.5-2°C/W

Fan-assisted heatsinks for better heat dissipation. Common for CPUs and power electronics.

💧 Liquid Cooling

Power > 100W, θ < 0.5°C/W

Water or liquid cooling systems for high-power applications requiring maximum heat removal.

Safety Status Indicators

✅

Safe Operation

Junction temperature is well below maximum rating with adequate safety margin

⚠️

Warning Zone

Junction temperature is close to maximum. Consider improved cooling solution

🚨

Critical Overheating

Junction temperature exceeds maximum rating. Immediate cooling improvement required

Common Use Cases

CPU Thermal Design

Calculate heatsink requirements for processors and microcontrollers. Typical desktop CPUs dissipate 65-150W and require junction temperatures below 85°C.

Power Electronics

Design cooling solutions for MOSFETs, IGBTs, and power modules. High-power switching devices often require active cooling or liquid cooling systems.

LED Thermal Management

Ensure proper thermal design for high-power LEDs and LED drivers to maintain light output and extend component lifespan.

Thermal Design Best Practices

1.Safety Margin: Always design with at least 10-20°C safety margin below maximum junction temperature
2.Thermal Interface: Use thermal paste or pads between component and heatsink for optimal heat transfer
3.Airflow: Ensure adequate airflow around heatsinks, especially in enclosed systems
4.Mounting: Proper heatsink mounting pressure is critical for thermal performance
5.Environment: Consider worst-case ambient temperatures in your thermal design

Why Use Our Heatsink Calculator?

Our heatsink calculator provides instant, accurate thermal analysis for electronic components. Whether you're designing cooling solutions for CPUs, power electronics, or LED systems, this tool offers the precision and convenience you need. With safety status indicators, cooling type recommendations, and comprehensive thermal calculations, it's the perfect companion for engineers, students, and hardware designers working on thermal management solutions.

Heatsink Calculator