PC Cooling Calculator
A fast graphics card can pour 300 watts of heat into your case, about as much as three old light bulbs. Pick your parts and fans to see if your cooling keeps up before you spend a cent on new fans.
Your result at full load
Checking your cooling
PC Airflow Simulator
See where the air goes in your case
Open your case with your fans in the 3D PC Airflow Simulator and see how much air reaches your graphics card and CPU cooler.
What Your Results Mean
- Heat to remove is the power your parts turn into heat at full load. Every watt a chip uses ends up as heat.
- Case airflow is how much warmer the air inside gets than your room. Within 10 °C is plenty. Past 18 °C, the graphics card and CPU cooler start breathing hot air.
- CPU cooler load is your processor's peak power as a share of what the cooler can handle in that air. Over 100% means the chip slows down to stay safe.
How the Numbers Work
The heat load adds your processor's peak power, your graphics card's board power and 50 W for the motherboard, memory, drives and fans. These are the same part figures our power supply calculator uses.
Air warms as it carries that heat out. The rise in °C is about 1.76 times the watts, divided by the airflow in CFM. This is the standard rule for sizing fans in a closed box, shown in °F in AutomationDirect's enclosure guide.
A case fan moves far less air than its box says. Grilles, filters and dust screens hold it back. In our simulator run of the Corsair 4000D Airflow, two stock fans at 1,200 RPM moved 21 and 35 CFM. So we count each 120 mm fan as 30 CFM at that speed, and each 140 mm fan as 40 CFM.
We take the stronger side, intake or exhaust, since the case vents make up the gap on the weaker side. Then we add 30 CFM, because the graphics card's own fans push warm air out through the vents, and warm air rises out on its own.
Airflow rises and falls in step with fan speed. A fan at half speed moves about half the air, as the fan laws show. That is why the fan speed setting changes your result.
Cooler makers rate a cooler for room-temperature air. DeepCool, for example, rates its single-tower AK400 at 220 W. Warmer case air leaves the cooler less room to work, so its rating shrinks as the case air warms.
How to Fix a Tight Result
If the case airflow is the weak spot, add a fan or run your fans a little faster. Our fan curve tool helps you pick speeds that ramp up only under load. Not sure which way new fans should blow? See whether top fans should be intake or exhaust.
If the CPU cooler is the weak spot, a bigger cooler is the fix. More case fans help a little, since they cool the air the cooler breathes. Check your intake and exhaust balance with the PC airflow calculator.
Building in a popular case? Our Corsair 4000D Airflow, NZXT H5 Flow, Lian Li O11, Lian Li V100 and Fractal North guides show which fan mounts help most, tested in the simulator.
What This Tool Cannot See
This check counts how much air your fans move. It cannot see where the air goes. A fan blowing straight out the back next to a front intake can move lots of air that never reaches the graphics card.
That is the job of the 3D PC airflow simulator. It runs air through your case and shows how much reaches the graphics card and CPU cooler. For tips on fan direction and placement, read the PC airflow guide.