Manufacturers publish liters per minute. Nobody converts that into how long your board takes. It is one division and it changes the purchase.
By Scooter M. · Published September 2, 2026 · Last updated September 2, 2026
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Every electric pump in this category publishes a flow rate in liters per minute. Not one of them tells you what that means for your board, which is odd, because the conversion is a single division and it is the only thing a buyer wants to know.
So here it is. The method is on the methodology page and repeated in short below, and every input is a published figure you can check.
The short version
A two-stage pump runs a fast, low-pressure fan to fill the shape, then a slow piston to pressurize. Those two rates are published separately.
Most of the air goes in during the second stage, so the high-pressure rate dominates the total time.
That is why the single-stage Bravo BP12 at a constant 160 L/min beats the two-stage Shark II, whose second stage is 70 L/min.
A 300 L board at 15 psi needs about 606 liters of free air. Filling the shape is only half of it; the other half is compression.
The arithmetic, in full
To take an empty chamber of volume V to gauge pressure P, you have to push in enough atmospheric-pressure air to fill the shape and then enough again to compress it:
free air = V x (14.7 + P) / 14.7
For a 300 L board at 15 psi that is 300 x 29.7 / 14.7 = 606 liters. Roughly half of that fills the shape and half compresses it, which is why the stage-two rate matters so much: the fast stage is doing the easy half.
A two-stage pump therefore takes V / stage1 + (V x P / 14.7) / stage2 minutes. A single-stage pump uses its one rate for both terms.
Minutes per board, per pump
Five of the eight boards in our registry publish a volume figure, so five of them can be calculated. The other three cannot be, by anybody.
Computed inflation time by pump and board
Board
Volume (L)
Shark II / Cachalot 2S
Bravo BP12
By hand (2 L pump)
Red Paddle Co Compact 9'6
200
3.5 min
2.5 min
3.2 min
GILI Air 10'6
225
3.9 min
2.8 min
3.6 min
Atoll 11'
238
4.1 min
3 min
3.8 min
Bluefin Cruise 10'8
260
4.5 min
3.3 min
4.2 min
NIXY Newport G5
300
5.2 min
3.8 min
4.8 min
Computed from published flow rates: OutdoorMaster 350 L/min stage one and 70 L/min stage two; Bravo BP12 160 L/min single stage. Hand-pump minutes assume a steady 40 full strokes per minute, which nobody sustains for a whole board. All figures are planning estimates from published specifications -- we have not timed any of them, because we do not own any of this gear.
What the table changes about the purchase
The headline flow rate is misleading, and now you can see by how much. The Shark II's 350 L/min is five times more than its own second stage, and it is the second stage that does most of the work. A pump advertised at 350 L/min and a pump advertised at 160 L/min are not what those numbers imply.
The other thing the table shows is that on a board of this size, an electric pump saves less time than people expect -- four to five minutes against roughly five minutes of hand pumping. What it saves is effort. Five minutes of standing still is not the same as roughly 190 strokes, the last sixty of which are single-action against 15 psi of back pressure. That is the honest case for buying one.
Corded or battery
The two OutdoorMaster pumps here publish identical flow rates, so the choice between them is entirely about where you inflate.
The corded Shark II runs off a 12 V car socket and will inflate boards until the car battery objects. It is 3.6 lb. The Cachalot 2S carries a 57 Wh battery, is 2.7 lb, and OutdoorMaster rates it at roughly three average boards per charge. If you always launch within a cable's reach of a car, the corded pump is strictly better. If you ever do not, it is useless and the battery pump is the only one of the two that works.
Best if you park at the waterOutdoorMaster Shark IIIt runs off a 12 V car socket, so it is a pump for a trailhead parking lot and useless once you have walked away from the car..
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The picks in full
No photoWe have no photograph of this exact model that we can honestly publish
#1 · Best electric pump
OutdoorMaster Cachalot 2S
The same two-stage 350 and 70 L/min pump architecture as the Shark II, on a 57 Wh internal battery. No car, no cord.
The same two-stage 350 and 70 L/min architecture as the corded Shark II, on a 57 Wh internal battery, at 2.7 lb. It works at water you have to walk to, which is the whole reason to buy one of these rather than pump by hand.
The trade-off
OutdoorMaster rates the battery at around three average boards per charge. That is a real constraint on a multi-day trip and there is no way to top it up without power.
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OutdoorMaster Cachalot 2S published specifications
No photoWe have no photograph of this exact model that we can honestly publish
#2 · Best if you park at the water
OutdoorMaster Shark II
A two-stage 12 V pump: 350 L/min to fill the shape, then 70 L/min to take it to 20 psi. Those two published rates are what make an honest inflation-time estimate possible at all.
Identical published flow rates, no battery to run down, and it will do board after board all day off a 12 V socket. If you drive to a launch, this is the one that makes sense.
The trade-off
It runs off a 12 V car socket, so it is a pump for a trailhead parking lot and useless once you have walked away from the car.
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No photoWe have no photograph of this exact model that we can honestly publish
#3 · Steadiest at the top end
Bravo BP12
A single-stage 12 V piston pump: 160 L/min all the way from limp to 14.5 psi, with an auto-stop. Slower off the line than a two-stage unit, steadier at the top.
A single-stage piston pump at a constant 160 L/min. Slower off the line than a two-stage unit but faster than one through the hard part, because 160 L/min at 12 psi is more than double the Shark II's stage-two rate.
The trade-off
One stage means no high-volume phase, so the first two minutes are noticeably slower than a Shark II. Its 14.5 psi ceiling also sits just under a 15 psi board.
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How long does an electric pump take to inflate a paddle board?+
For a 300 L board at 15 psi, our arithmetic puts the OutdoorMaster Shark II at about 5.2 minutes and the Bravo BP12 at about 3.8. Both are computed from the manufacturers' published flow rates and the board's published volume -- the full working is in the table below. By hand on a 2 L dual-action pump the same board is roughly 190 strokes, or about 4.8 minutes of continuous effort.
Why is the single-stage Bravo faster than the two-stage OutdoorMaster?+
Because most of the work is at high pressure, and that is where the two-stage pump slows down. The Shark II moves 350 L/min while it is filling the shape, then drops to 70 L/min to pressurize. The BP12 holds 160 L/min throughout. Filling the shape is a small fraction of the total air, so the pump that is quicker at pressure wins overall -- even though it is less than half the speed at the start.
Is a battery pump worth carrying?+
The Cachalot 2S is 2.7 lb, and a dual-action hand pump is about 1.65 lb, so you are carrying roughly one extra pound to convert five minutes of hard work into five minutes of standing still. Against a 50 lb airline allowance that is a cheap pound. The constraint is charge: OutdoorMaster rates the battery at around three average boards, which matters on a multi-day trip with no power.
Will an electric SUP pump work on an inflatable kayak?+
Yes, and it is overkill in an interesting way. Kayaks in our registry run 1.1 to 6 psi against a board's 15, so the pump barely enters its high-pressure stage. What matters is the valve fitting -- the Bravo 4 hand pump ships with common adapters and the electric pumps generally do too, but check yours against the valve type your boat uses.
Units we claim to have tested: 0
Everyone in this category says they tested twenty boats. We have not tested any, and we say so. What we did instead: pulled the published specifications and the owner's manuals, computed the pump load and the packed volume for every model that publishes enough to compute them, checked the packed sizes against the airline limits you will actually meet, and cited every page we read. The full method.
Sources
Every specification on this page was read from one of these, on the date shown. Specs change between model years, so the date matters as much as the link.
