Ranked by decibels: noise first, airflow secondQuietest we list: CAT-1P1060S · 56 dB
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VIAIR · Model 400P (40043)

VIAIR 400P Portable 12V review

400PdB n/a
Illustration: 12V portable

VIAIR's popular off-road 12V compressor: 2.30 CFM free flow, 150 PSI max and a 33% duty cycle at 100 PSI, sized for tires up to about 35 inches.

Our rating: 4.4 / 5#1 in 12 voltUpdated October 18, 2026By the Silent Air Compressor editors · How we pick

Check price on Amazon$150–$300

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Full specifications

Noise ratingNot published
Noise source—
CFM at 90 PSI—
CFM at 40 PSI—
Free-flow CFM (0 PSI)2.3
Max PSI150
TankNo tank
Horsepower—
Pump—
Stages—
Power12V vehicle
Duty cycle33% at 100 PSI
Weight10.4 lb
Price band$150–$300 (checked October 18, 2026)

A dash means the manufacturer doesn't publish that figure. We never estimate one.

Our take

The 400P is the 12V compressor many off-roaders carry to re-inflate after airing down. VIAIR lists 2.30 CFM at 0 PSI, a 150 PSI maximum and a 33% duty cycle at 100 PSI.

It draws up to 30 A, so it connects straight to the battery, and it weighs about 10.4 lb in its carry bag.

We found no published noise rating. For passenger cars, the smaller 88P is plenty. For 33–35 inch tires, the 400P is worth the extra cost.

Pros

  • Fast enough for large truck and off-road tires
  • 150 PSI max
  • IP54 rated

Cons

  • Draws up to 30 A, so it must clamp to the battery
  • No published noise rating

What it can run

This is a tankless inflator: it is built for tires and inflatables and can't run air tools.

Open the CFM calculator

Who it's for, and who should skip it

Best for: Airing up off-road and truck tires after the trail.

Buy it if: you air up car, truck or off-road tires away from home; you move it around often (about 10.4 lb).

Skip it if: you want to run nailers or air tools (it has no tank); you need to work indoors or near people without hearing protection.

How it compares in its class

  • Ranked #1 of 3 in 12 volt.
  • No published noise rating, unlike 2 of the 3 models in that list.
  • Price band $150–$300; see every spec side by side in the comparison table.

Ownership tips

  • Clamp it straight to the vehicle battery and keep the engine running while inflating to hold voltage up.
  • Respect the duty cycle: let it cool between tires on large trucks.
  • Coil the hose loosely and keep the air filter clean, especially after dusty trail use.

General guidance; always follow the owner's manual. More in our maintenance checklist.

VIAIR 400P Portable 12V: quick answers

How loud is the VIAIR 400P Portable 12V?

The manufacturer doesn't publish a noise rating, so we can't place it on our decibel scale. Treat it as typical for its class.

What can the VIAIR 400P Portable 12V run?

It is a tankless inflator for tires, bikes, balls and other inflatables. It can't run nailers or air tools.

Is the VIAIR 400P Portable 12V oil-free?

The listing doesn't state a pump type.

What power does the VIAIR 400P Portable 12V need?

It runs from a vehicle's 12V system, clamped to the battery.

Spec sources

Where each figure on this page comes from (checked October 18, 2026). We don't present manufacturer figures as our own measurements.

  • viaircorp.com: free-flow CFM, max PSI, duty cycle, weight
  • Amazon product listing: tank

Alternatives to consider

Appears in: 12 volt