Best Power Supply Raspberry Pi 4: CanaKit Leads

The best power supply raspberry pi 4 owners should buy first is the CanaKit 3.5A USB-C unit, because its 3.5A rating leaves the most headroom above the board's 3A floor and its 18 AWG, 5ft cable resists the voltage drop that triggers undervoltage warnings. If you'd rather buy from the people who made the board, the official Raspberry Pi 15W supply delivers 5.1V at 3 amps on a 1.5m cable. The deciding number here is amperage under load, not the wattage on the box. Every unit in this set clears 3A on paper. Only two clear it with room to spare.

Best power supply raspberry pi 4 at a glance

How I matched five listings to five buyer profiles

I started from the buyer, not the spec sheet. Five people shop this category, and each one needs a different unit.

The Pi 4 owner with peripherals hanging off every port needs current headroom. That points at the two units rated above 3A. The person who wants the board maker's own accessory and a stated warranty period needs the official supply. The maker with a drawer full of single-board computers needs one adapter that covers several of them. The person running a stock board with a keyboard and mouse needs the cheapest unit that still clears 3A. And the person building something into a case behind a desk needs a short cable and a long warranty.

Here's how I read the data for each:

1. Published current rating. 3A is the floor for a Pi 4. Anything below it was out before I looked further.
2. Cable length and gauge. A 5ft run at 18 AWG behaves differently from a 3.3ft run with no stated gauge.
3. Switch or no switch. Three of these five list one. That is a real usability split.
4. Stated warranty. Only three listings publish a term.
5. Safety listing. UL, ETL, or unstated. Worth knowing before it lives under a desk.

That produced five picks and five clean profiles, which is the whole point.

1. CanaKit 3.5A Raspberry Pi 4 Power Supply — Best overall

The only unit here rated at 3.5A, with the cable specification to actually deliver it.

Best for: a Pi 4 running SSDs, cameras or a HAT off the board Skip it if: you need a switch on the cable

Amperage is where this one separates itself. Every other pick in the set sits at 3A or advertises 4A without a published figure in the specifications. CanaKit lists 3.5A outright as the size spec, which is half an amp of margin above what the board asks for. That margin is what stops the lightning-bolt warning appearing when a bus-powered drive spins up.

The cable matters just as much. CanaKit states 18 AWG at 5ft. Thicker wire over a fixed distance means less voltage sag at the far end, and 5ft is enough to reach a wall outlet from a desk. The brand also says the unit includes a noise filter for added stability, which is a manufacturer claim rather than a measured result, but it is the only supply here that mentions filtering at all.

At 5.61 oz it's the joint-heaviest pick, tied with the iUniker. The trade-off against the rest of the set is convenience: there's no on/off switch, so powering down means pulling the plug or shutting down in software first. Three cheaper units in this group give you a switch.

Pros:

• Highest published current rating in this set at 3.5A
• 18 AWG cable gauge stated, unlike most rivals here
• 5ft cable reaches a wall outlet from a desk
• Noise filter claimed for added stability
• Second-cheapest of the five

Cons:

• No on/off switch, unlike three other picks
• Joint-heaviest unit here at 5.61 oz
• No warranty term published on the listing
• Only one seller lists it

2. Raspberry Pi 15W USB-C Power Supply US — Best premium

The board maker's own supply, with a published 12-month warranty and the tightest voltage figure in the set.

Best for: anyone who wants the board maker's own unit and a stated warranty Skip it if: your outlet sits more than five feet from the Pi

Raspberry Pi lists this as DC 5.1V at 3 amps, 15.3 watts, on a 1.5m 18AWG cable. The 5.1V figure is the interesting part. Nudging the output a tenth of a volt above nominal is a standard way of compensating for drop along the cable, so what arrives at the USB-C socket lands closer to 5V under load. It's the same trick the Smraza uses.

This is the most expensive pick here, and it's also the one that comes with a 12-month warranty printed in the specifications. Model SC0218, released in 2020. At 3.84 oz it's among the lighter units, and the listing gives full dimensions of 2.05 x 3.23 x 2.44 in, so you can check outlet clearance before ordering.

Two sellers stock it, more than any other pick in this group. What you don't get is current headroom. It sits at 3 amps, exactly the board's requirement, where the CanaKit gives you 3.5A for less money. There's no on/off switch either, and 1.5m is shorter than the 5ft runs on three rivals.

Pros:

• 5.1V output helps offset cable voltage drop
• 12-month warranty published on the listing
• 18AWG cable gauge stated
• Full dimensions listed for outlet clearance
• Two sellers stock it

Cons:

• Most expensive pick here with no extra current over 3A
• No on/off switch
• 1.5m cable is shorter than three rivals
• No headroom above the board's 3A minimum

3. iUniker 5V 4A USB-C Power Supply for Raspberry Pi 4 — Most versatile

The widest compatibility list in the set, with a switch and a UL listing on top.

Best for: a maker powering a Pi 4 today and an Orange Pi 5 next month Skip it if: you plan to move to a Raspberry Pi 5

iUniker claims 5V at 4A, 20W maximum, and says the unit is tested and optimised for the Pi 4 Model B across the 1GB to 8GB range. The listing also names the Orange Pi 5 and 5B as supported boards. That breadth is what earns the award: if your bench has more than one single-board computer on it, this is the one adapter that covers the most of them.

It's the slimmest body here at 0.79 x 3.15 x 1.57 in, which matters on a crowded power strip. The 5ft cable matches the CanaKit for reach, and the built-in on/off switch means you're not wearing out the USB-C socket with repeated insertions. iUniker states a UL listing with over-current, over-voltage and short-circuit protection, plus 100 to 240V input for travel. Warranty is one year from the manufacturer.

The important limit is written into the listing itself: iUniker says it is not compatible with the Pi 5's higher power requirement. Buy this as a Pi 4 supply, not as a bridge to your next board. No cable gauge is published either, which makes the 4A claim harder to trust than CanaKit's 3.5A.

Pros:

• Covers Pi 4 Model B 1GB to 8GB plus Orange Pi 5/5B
• Built-in on/off switch spares the USB-C port
• Slimmest body in this set at 0.79 in deep
• UL listed with over-current and short-circuit protection
• One-year manufacturer warranty stated

Cons:

• Listing states it will not power a Raspberry Pi 5
• No cable gauge published to support the 4A claim
• Joint-heaviest at 5.61 oz
• Only one seller lists it

4. Smraza Smarza 5.1V 3A Power Supply Charger for Raspberry — Best budget pick

The cheapest pick here, and it still clears 3A with a switch and an ETL listing.

Best for: a stock Pi 4 with a keyboard, mouse and nothing else Skip it if: you hang bus-powered drives off the USB ports

This is the cheapest of the five and it doesn't cut the specification that matters. Smraza publishes 100-240V AC input and 5.1V 3A output, with a 5ft cable listed as 60in in the size spec. That's the same voltage strategy as the official supply, at the lowest price position in this group.

You also get the on/off switch, which the two most expensive picks here skip. Smraza states ETL listing, and the listing describes compatibility with the Pi 4 Model B in 1GB, 2GB and 4GB versions as well as the Pi 3. At 3.84 oz it's tied for lightest. The company adds a satisfaction promise in its bullets, which is marketing language rather than a warranty term.

Where it loses is headroom and paperwork. 3A is exactly the board's requirement, so a spinning USB drive or a power-hungry HAT leaves nothing in reserve. No cable gauge is published, no warranty period is stated, and the compatibility list stops at 4GB rather than naming the 8GB board. If your Pi 4 does more than browse and code, spend a little more on the CanaKit.

Pros:

• Cheapest pick in this set
• 5.1V output offsets cable drop
• On/off switch included
• ETL listed with stated 100-240V input
• 5ft cable, tied for the longest here

Cons:

• No current headroom above the 3A minimum
• No cable gauge published
• No warranty term on the listing
• Compatibility list stops at the 4GB board
• Only one seller lists it

5. LitStar 5V 3A USB Type C Adapter for Raspberry Pi 4 Model — Best warranty

Longest published warranty here at 18 months, on the lightest and shortest-cabled unit in the set.

Best for: a tucked-away build where the plug sits close to the board Skip it if: you need slack in the cable

Three listings in this set publish a warranty. LitStar's is the longest at 18 months, six months more than the official supply's 12. For a component that sits plugged in permanently and fails silently, a longer term has real value.

The rest reads lean. Output is 5V 3A with 100V-240V 50/60Hz input, and LitStar names the Pi 4 and Pi 4 Model B specifically. There's an on/off switch, and the brand claims a built-in protection mechanism covering short circuit, over current, over voltage and over temperature. At 23 g it's by far the lightest unit here, which is convenient on a multi-outlet strip.

The cable is the catch. At 3.3 feet it's the shortest in this group by a wide margin, roughly a foot and a half less than the 5ft runs on three rivals. That rules it out for anything more than an arm's reach from an outlet. It also sits in the more expensive half of the set while offering 3A rather than the CanaKit's 3.5A, and no cable gauge is published. The colour spec reads as a product description rather than an actual colour, which tells you how thin the listing is.

Pros:

• 18-month warranty, longest published term here
• On/off switch included
• Lightest unit in this set at 23 g
• Claimed over-current, over-voltage and over-temperature protection

Cons:

• Shortest cable here at 3.3 feet
• Priced above the CanaKit while offering less current
• No cable gauge published
• Thinnest specification list of the five
• Only one seller lists it

Why does amperage decide the best power supply raspberry pi 4?

Undervoltage is the failure mode that sends people shopping for a new supply. The board detects a dip below its threshold, throttles the CPU and drops a warning icon on screen. Nothing breaks, but performance falls off a cliff and SD card corruption becomes more likely.

The Pi 4 asks for 5V at 3A. Every pick here meets that on paper, so the specification on the box does not separate them. What separates them is what's left over.

• At exactly 3A, the official supply, the Smraza and the LitStar have no reserve. A keyboard, mouse and HDMI monitor are fine. A bus-powered SSD plus a camera module is where it gets tight.
• At 3.5A, the CanaKit gives you half an amp of margin, and it's the only figure in this set that appears in the specifications rather than only in a marketing bullet.
• At a claimed 4A, the iUniker advertises the most, but with no published cable gauge that number is harder to bank on.

Cable is the second half of the equation. Voltage drops along copper, and thinner copper drops more. CanaKit and Raspberry Pi both publish 18 AWG. Nobody else publishes a gauge at all. That's a meaningful gap when you're choosing the best power supply raspberry pi 4 units for a build that draws real current.

Does the on/off switch matter more than the wattage?

For a lot of Pi 4 builds, yes. Here's the trick with USB-C: the connector is rated for a finite number of insertion cycles, and a Pi that gets power-cycled twice a day is racking those up fast. An inline switch moves the wear from the board's port to a component you can replace.

Three of these five list a switch. The iUniker, the Smraza and the LitStar all have one. The CanaKit and the official Raspberry Pi supply do not.

That split maps neatly onto use cases:

• Always-on server, NAS or Pi-hole. You almost never cut power. Skip the switch and buy current headroom instead.
• Kiosk, classroom cart or shared bench. The Pi goes on and off constantly. iUniker specifically pitches its switch at this, saying it extends cable and port lifespan.
• Project you're actively developing. You'll reboot dozens of times a day, and a switch beside your keyboard beats reaching behind a desk.

One warning worth stating plainly: a switch is not a substitute for a clean shutdown. Cutting power to a running Pi risks the SD card filesystem. The switch saves your USB-C port, not your data.

What the listings do not tell you about USB-C

The keyword here mentions the Pi 4 specifically, and every listing in this set names it. But "USB-C power supply" hides a few things these listings do not resolve, and you should know them before you buy.

Not every USB-C charger works. A high-wattage laptop charger negotiates voltage over USB Power Delivery. The Pi 4 wants a plain 5V rail. A charger that only offers 9V or 20V profiles will not power the board, which is why a purpose-built 5V adapter beats whatever's in your drawer.

Total draw includes your peripherals. The 3A figure covers the board and everything hanging off its USB ports. A bus-powered 2.5-inch drive can take a full amp on spin-up.

Cable gauge is often silent. Three of these five listings don't publish one. That's not proof of thin wire, but it means the current rating is unverified at the far end.

Pi 5 compatibility is a separate question. iUniker states outright that its unit will not meet the Pi 5's requirement. Treat any supply in this category as a Pi 4 purchase unless the listing says otherwise.

Colour and size specs can be junk. LitStar's colour field reads "5V 3A USB-C adapters". Read the feature bullets, not just the spec table.

Which best power supply raspberry pi 4 fits your build?

Work down this list and stop at the first line that describes you.

• You run a Pi 4 with an SSD, camera or HAT. CanaKit. The 3.5A rating and 18 AWG cable are the two figures that matter, and no other pick publishes both.
• You want the manufacturer's own accessory with a warranty. Official Raspberry Pi 15W. 5.1V, 3A, 12 months, model SC0218.
• You own more than one single-board computer. iUniker. It's the only pick naming the Orange Pi 5 and 5B alongside the Pi 4.
• Your Pi 4 is a stock desktop or learning machine. Smraza. Cheapest here, 5.1V 3A, switch included, ETL listed.
• The plug sits within arm's reach and you want the longest cover. LitStar. 18 months, the longest term in this group, on a 3.3ft cable.
• You reboot constantly. Any of the three with a switch: iUniker, Smraza or LitStar.
• Your outlet is across the room. CanaKit, iUniker or Smraza. All three list 5ft.

Two thresholds are worth memorising. Below 3A, walk away. Above 3.3ft of cable, you have desk-to-wall reach; below it, you don't.

The verdict

The CanaKit 3.5A is the default recommendation for a Pi 4, and the reasoning is short. It publishes the highest current rating in this set, it publishes an 18 AWG gauge on a 5ft cable, and it sits second-cheapest of the five. Nothing else here combines a real margin above the board's 3A requirement with a stated cable specification, and those two numbers are what determine whether you ever see an undervoltage warning.

Two conditions flip that pick. First, if you power-cycle the board more than a couple of times a day, buy a supply with a switch instead. The iUniker is the strongest of those three, with a claimed 4A output, a UL listing, a one-year warranty and the slimmest body in the group at 0.79 in deep. Second, if a stated warranty term is the thing you want, the CanaKit doesn't publish one and the LitStar publishes 18 months, the longest here.

The official Raspberry Pi 15W supply is the runner-up, and its exact advantage is provenance plus paperwork: it's the board maker's own unit, it publishes 5.1V to compensate for cable drop, it lists 18AWG, and two sellers stock it. It costs the most and gives you no current headroom for the money, which is the only reason it isn't first.

FAQ

Is a more expensive power supply worth it for a Pi 4?

A more expensive power supply is worth it only when it buys a specification you'll use. Here, the most expensive picks are the official Raspberry Pi unit and the LitStar, and neither exceeds 3A. The CanaKit sits second-cheapest with a 3.5A rating and a published 18 AWG cable. Spend up for a warranty term or brand provenance, not automatically for performance.

Can I use a phone charger instead of a Raspberry Pi 4 supply?

Using a phone charger instead of a purpose-built supply often fails, because many USB-C chargers negotiate higher voltages over Power Delivery rather than holding a steady 5V rail. The Pi 4 needs 5V at 3A minimum. A dedicated adapter like the Smraza at 5.1V 3A removes the guesswork, and the 5.1V figure specifically compensates for drop along the cable.

What does the best power supply raspberry pi 4 need to output?

The best power supply raspberry pi 4 owners buy needs at least 5V at 3A. That covers the board plus whatever draws power from its USB ports. The CanaKit's 3.5A gives you half an amp of reserve for a bus-powered SSD or camera. Anything advertising less than 3A should not be on your shortlist at all.

CanaKit 3.5A or the official Raspberry Pi 15W supply?

Between the CanaKit 3.5A and the official Raspberry Pi 15W supply, choose on headroom versus warranty. CanaKit publishes 3.5A and a 5ft 18 AWG cable at a lower price position. The official unit publishes 5.1V 3A, a 1.5m 18AWG cable and a 12-month warranty. If peripherals draw real current, take the CanaKit. If paperwork matters more, take the official.

Will these supplies power a Raspberry Pi 5?

These supplies will not reliably power a Raspberry Pi 5. iUniker states outright that its 5V 4A unit is not compatible with the Pi 5's higher power requirement, and no other listing in this set claims Pi 5 support either. Treat every pick here as a Pi 4 purchase. If a Pi 5 is in your plans, budget for a separate adapter.

Start with the CanaKit unless one of the two conditions above applies to you, because the two numbers it publishes, 3.5A and 18 AWG, are exactly the two that decide whether your board throttles under load. A supply is the cheapest component in a Pi build and the one most likely to cause problems that look like software faults. Check your outlet distance first, count what's plugged into the USB ports, then pick the row in the table that matches. Every link above goes straight to the current listing.

Last updated: September 17, 2026. Product availability re-checked.

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