Raspberry Pi 5
can be powered by a range of USB-C power supplies (PSU), but to get
the best
experience (especially with USB devices)
it needs a high-quality 5V 5A USB-C power supply.
Below we explain why the official 27W PSU is recommended, what it
enables, and what to expect if you use a 15W / 3A PSU instead.
🔌 Which power supply does Raspberry Pi 5 need?
Raspberry Pi 5 is designed to be powered via USB-C and is intended for a 5V / 5A supply for best performance and stability (this is what allows the Pi to run comfortably while also powering connected devices).
Official 27W Raspberry Pi 5 power supplies provide a stable 5.1V / 5A output and are the most reliable option if you want to avoid power-related warnings, drop-outs, or USB devices failing to start.
✓ Recommended:Raspberry Pi 27W USB-C Power Supply (standard choice for Pi 5) or Raspberry Pi 45W USB-C Power Supply (also works for Pi 5, plus extra USB-C PD modes for other devices).
⚡ What the 27W (or 45W) PSU enables
Raspberry Pi 5 can “talk” to a compatible USB-C Power Delivery (PD) power supply. When it detects a proper 5A supply, it can safely allow more power to be used by devices plugged into the Pi’s USB ports.
By default, the total power available to USB devices is limited to a nominal 600mA. When an official 5A USB-C PD supply is detected, Raspberry Pi 5 automatically raises this to a nominal 1.6A, which is much better for higher-power peripherals (for example USB SSDs, hard drives, and other power-hungry USB devices).
✓ Why it matters: If you plan to use an SSD/HDD, multiple USB devices, or anything that draws more power from USB, a 5V 5A PSU helps keep things stable and avoids devices disconnecting or failing to start.
🔻 What happens if you use a 15W / 3A PSU?
A lower-powered USB-C supply (including many 5V / 3A phone/laptop chargers and the Raspberry Pi 4 15W USB-C PSU) will often power on a Raspberry Pi 5, but you may run into limitations, especially once you connect USB devices or put the Pi under load.
⚠️ Common symptoms of an under-powered PSU: under-voltage warnings, random reboots, USB devices failing to show up, USB storage disconnecting, or unstable behaviour under load. If you see these, we recommend switching to an official 5V 5A PSU (27W or 45W).
🧠 27W vs 45W: which should I choose?
For powering a Raspberry Pi 5, both the 27W and 45W official power supplies provide the important part: a stable 5.1V / 5A mode, so Pi 5 can run without the common low-power limitations.
The main reason to choose the 45W PSU is if you want a more general-purpose USB-C PD supply for other devices too (it supports additional higher-voltage PD modes for compatible equipment). For most Raspberry Pi 5 setups, the 27W PSU is the standard recommended choice.