True power consumption offers you the most accurate PC power consumption calculator on the web for free. It's a must tool for estimating the power consumption of a modern desktop PC.
It can be used to select a proper power supply unit for your system. It can also be used to calculate the cost of electricity as well as optimize the parts for energy efficiency or low noise levels.
The calculator estimates both the idle and full load power consumptions and recommends a PSU wattage rating for the selected components.

How does it work?

A typical PSU calculator works by calculating the power requirements from the Thermal Design Power (TDP) values from some main parts on the system. However TDP is only a specification of how much power the cooling system should dissipate for the component to stay within the thermal limits in extreme conditions. Many assumptions and predictions has to be made to give you a rough estimate of the total system power. In many cases, that's not the actual power. We on the other hand, have gathered thousands of results from various real-world benchmarks and manufacturer data sheets to extract the real power of these components. By doing so, we can increase the accuracy significantly and also estimate the idle power consumption of the system.

Change CPU count only if the system has more than 1 physical CPU. To prevent confusion, only modern CPUs are listed.
CPU overclocking
Change CPU speed to overclock or underclock. Change Vcore to adjust core voltage from stock value.
Change RAM count to match the physical RAM sticks installed in the system. RAM size does not affect the results.
Video cards
X Linked (SLI / CF)
X Linked (SLI / CF)
If theres multiple cards, select "Linked" if cards are linked together with ATI CrossFire or nVidia SLI bridges. Linking is taken into account only if video card count is higher than one per row. Choose the second card only if there are different cards on the system. OC marking in the end means the card is an overclocked model.
Solid state disk drives
Hard disk drives / Hybrid disk drives
All hard drives on the list are 3.5 inch models unless mentioned otherwise.
Common devices
PCI / PCI-express cards
X 80mm
X 92mm
X 120mm
X 140mm
X 200mm
Include all fans on the system except for the fans that are driven from the part itself (GPU fans and PSU fans).
Other devices
X USB devices
X FireWire devices
Include all USB and FireWire devices on the system, except for the keyboard and mouse (since they can already be included in common devices).
Computer is on
We use this information to compensate the recommended wattage against capacitor aging.
After selecting all the components on your system, press "Calculate" to view the results

To be noted

The results do not include PSU power losses or devices connected to external power sources like monitors and printers.
We assume the system has a single monitor attached to the GPU. If you have a multimonitor setup, the results may vary.
We assume the system is working in a power saving mode if available.
We assume the system fans are temperature controlled.
We do not take the system start-up power surge into account. Systems with numerous hard drives may encounter a large start-up power peak.
When selecting a proper power supply unit, pay attention to the +12V rail power ratings. Modern computers use the 12V rails to generate most of the voltages in the system.

Version history

February 4th, 2014 First version released
February 13th, 2014 Added over 100 hard disks and SSD drives. Added 200mm fan
February 19th, 2014 Added over 200 older CPU models. Added CPU overclocking options.
April 15th, 2015 Added many new CPU, GPU and SSD models.


If you found this site useful, consider donating some bitcoins or litecoins to support the future development of the site.
Bitcoin: 17Kiqs3djHaberdJ7ih4vtboJ5wFU7JeFn
Litecoin: LKgo2Saabsh33Ro1y8iH9Lzx91mLemgAx4