Flight profile · United Airlines

UA1233

Denver (DEN) to Newark (EWR) · scheduled 11:35 AM – 5:30 PM

This page describes how UA1233 has historically performed, which is a different and more useful question when you are deciding what to book. The live position below is a reading from receivers on the ground, not flight status. For today’s status, check with United Airlines.

How UA1233 performs

707 operations, May 2024 – July 2026.

On-time arrivals
70.7%
487 of 689 completed
Cancellation rate
1.27%
9 cancelled
Median arrival delay
-4 min
Average 13.5 min
Severe delays
10.9%
Arrived 60+ minutes late
Delay when late
73 min
Average, when 15+ min late
Departure punctuality
71.2%
Left the gate on time

UA1233 arrived on time 70.7% of the time, against 75.0% for all DEN → EWR flights, so this departure is 4.3 percentage points worse than the route as a whole. Against United Airlines’ own flights on this route it is 4.3 points worse.

Source: US DOT Bureau of Transportation Statistics · 707 operations, May 2024 – July 2026 · If UA1233 is cancelled or significantly changed, DOT’s automatic refund rule may entitle you to your money back. The refund checker walks through eligibility.

Where UA1233 is right now

A live reading, only if you ask for it. It is not part of the reliability record above.

Ask for the position of UA1233 right now, if receivers on the ground are hearing it. Nothing is requested until you press the button.

Against the rest of the route

Against the rest of the route
Flight or routeOn timeCancelledMedian delaySevereFlights
UA123370.7%1.27%-4 min10.9%707
United Airlines on DEN → EWR75.0%2.16%-6 min10.8%9,876
All DEN → EWR flights75.0%2.16%-6 min10.8%9,876

Source: FlyerIntel analysis of US DOT BTS data · May 2024 – July 2026

Why UA1233 runs late

Where US DOT attributed the delay minutes on this flight.

Share of the delay minutes US DOT attributed to each cause for UA1233 on DEN → EWR. Only delays of 15 minutes or more are attributed.

Source: US DOT Bureau of Transportation Statistics · Data covering May 2024 – July 2026

Does a late aircraft delay this flight?

How often the plane that flies UA1233 comes in late, and what that does to the departure.

Inbound aircraft late
11%
69 of 617 departures came in 15+ minutes late
Scheduled time on the ground
80 minutes
Median at DEN between the inbound and this departure

The aircraft flying UA1233 came in 15 or more minutes late on 11% of the departures where its previous flight is known. There are not enough departures in both groups to say how the flight left after a late one and after an on-time one.

Each departure is matched to the flight the same aircraft flew into DEN just before it, using the tail number in the DOT file, 617 of 698 departures in all. A departure is left out when that flight is unknown, was cancelled or diverted, or the aircraft had sat for more than 12 hours. A flight the airline cancelled never left and is not in the count, and one flown by a substitute aircraft is matched to the aircraft that flew it, not to the one first planned.

Against the network at the same turn length

UA1233 against all flights with a scheduled turn of 60 to 89 minutes
Share of departuresInbound landed 15+ late
UA123311%
Network, same turn17%

The schedule leaves a normal turn: enough time to clean and board if the aircraft is on time, little to spare if it is not.

The network row is every flight with a scheduled turn of 60 to 89 minutes. How often UA1233’s aircraft landed 15 or more minutes late is lower than the network’s. There are not enough departures in both groups to compare how it left.

More: Which Flight Numbers Pay for a Late Aircraft lists the flight numbers that pass a late aircraft on.

Source: US DOT Bureau of Transportation Statistics · Data covering May 2024 – July 2026

From pushback to gate

When it leaves DEN late, does that still matter by the time it reaches EWR?

Leaves the gate
22.2 minutes late
Average over 698 pushbacks
Taxi out at DEN
21.7 min
19.9 min for the airport in this hour
Taxi in at EWR
10.8 min
10.1 min for a typical EWR arrival
Reaches the gate at EWR
13.5 minutes late
Average over 689 arrivals

UA1233 pushes back an average of 22.2 minutes late and reaches the gate at EWR an average of 13.5 minutes late. The 8.6 minutes between those two figures are slack the published schedule already carries, which is why a late pushback on this flight does not reliably become a late arrival. It spends 21.7 minutes on the taxiways at DEN, 1.8 minutes longer than a typical DEN departure in the same hour.

On arrival at EWR, UA1233 spends 10.8 min taxiing from touchdown to the gate — ground time a connecting passenger sits through before they can even leave the aircraft, on top of however late the flight itself ran. That is about what any arrival at EWR spends on the ground before reaching the gate.

Departure delay is averaged over every pushback and arrival delay over every completed arrival, so the two counts differ by the flights that never reached EWR. Taxi-out is gate to wheels up and sits inside the scheduled block rather than on top of it; the comparison is 94,079 departures from DEN scheduled in the clock hour UA1233 most often leaves in. Taxi-in is landing to gate, compared against every arrival FlyerIntel has on file at EWR (387,854 flights), not just UA1233’s own. More on taxi time.

Source: FlyerIntel analysis of US DOT BTS data · May 2024 – July 2026

The hour it leaves DEN

Part of any flight’s record belongs to the clock rather than to the flight. UA1233 has one departure time, so this is what that time is worth.

UA123370.7%
All DEN departures, 11 AM–12 PM80.0%
All DEN departures, whole day76.0%

On-time arrival rate. 94,079 departures from DEN are scheduled in the 11 AM–12 PM hour over the period, against 963,099 across the whole day.

UA1233 is scheduled out of DEN at 11:35 AM, in the 11 AM–12 PM bank. Departures from DEN in that hour arrive on time 80.0% of the time against 76.0% across the airport’s whole day — the slot alone is worth 4.0 points better before anything about this particular flight is considered.

The two airport figures cover every departure from DEN to every destination, so they describe the slot rather than this journey — the like-for-like comparison against the route is above. Hours are scheduled local, and a number whose schedule moved between banks inside the period has no single hour and is not described here at all. Why the hour matters.

Source: FlyerIntel analysis of US DOT BTS data · May 2024 – July 2026 · Hours below 120 departures are not scored.

Other routes UA1233 has flown

A flight number is a slot in a schedule, and carriers reassign it. These are the other city pairs this number served in the analysis period.

Other routes UA1233 has flown
RouteOperatedFlightsOn time
EWR→RDU Newark to Raleigh–DurhamJune 25, 2026 – July 31, 202632—
SFO→DEN San Francisco to DenverJanuary 6, 2026 – June 24, 202671—
EWR→FLL Newark to Fort LauderdaleMarch 5, 2026 – April 29, 202656—
SAN→DEN San Diego to DenverFebruary 12, 2026 – March 4, 202621—
EWR→PBI Newark to West Palm BeachJanuary 8, 2026 – March 1, 202629—
ORF→DEN Norfolk to DenverDecember 18, 2025 – January 5, 202619—
TUL→DEN Tulsa to DenverDecember 2–17, 202516—
EWR→IAH Newark to HoustonOctober 26, 2025 – December 1, 202536—
XNA→DEN Fayetteville/Springdale/Rogers to DenverAugust 19, 2025 – September 1, 202514—
SJC→DEN San Jose to DenverJune 26, 2025 – August 18, 202554—
EWR→RSW Newark to Fort MyersMay 22, 2025 – June 25, 202535—
EWR→SFO Newark to San FranciscoFebruary 13, 2025 – March 5, 202521—
FSD→DEN Sioux Falls to DenverJanuary 8, 2025 – February 12, 202536—
LAS→ORD Las Vegas to ChicagoJanuary 7, 20251—
EWR→CLT Newark to CharlotteSeptember 5, 2023 – May 22, 202413778.9%
BWI→IAH Baltimore to HoustonMarch 31, 2024 – May 1, 202428—
MIA→EWR Miami to NewarkApril 6–27, 20244—
SAT→EWR San Antonio to NewarkMarch 7–28, 202410—
LAX→IAH Los Angeles to HoustonMarch 10–24, 20243—
SFO→EWR San Francisco to NewarkFebruary 15, 2024 – March 6, 202421—
MSP→EWR Minneapolis to NewarkDecember 21, 2023 – January 8, 202419—
ORD→SEA Chicago to SeattleOctober 29, 2023 – November 27, 202330—
MKE→IAH Milwaukee to HoustonOctober 1–28, 202328—
DEN→IAH Denver to HoustonSeptember 23, 20231—
ORD→BUF Chicago to BuffaloSeptember 8–22, 20233—
EWR→BTV Newark to BurlingtonAugust 1, 2023 – September 4, 202332—
IAH→EWR Houston to NewarkJuly 1–31, 202331—

Because the same number has served different journeys, the statistics above describe only the route UA1233 currently operates. Blending them would produce an average of two different flights.

When it goes wrong

The average describes a usual day. This is the day that ruins a connection.

One arrival in ten is worse than

62 min late

against a median of 4 min early

Arrived an hour or more late10.9%
Typical delay when late73 min
Cancelled1.27%
Landed somewhere else1.27%

UA1233 has an average that understates its risk: a typical arrival is 4 min early, but the worst tenth are 66 minutes worse than that. If the trip has something unmissable at the end of it, the median is the wrong number to plan against.

Percentiles over 707 operations; cancelled and diverted flights are counted separately.

Source: US DOT Bureau of Transportation Statistics · Data covering May 2024 – July 2026

Other flights on this route

Same airports, same journey, different odds of arriving on time.

Other flights on this route
FlightAirlineOn timeMedian arrivalOperations
UA2345United Airlines94.0%16 min early795
UA1233 this flightUnited Airlines70.7%4 min early707
UA1715United Airlines65.0%3 min early946
UA2613United Airlines62.6%4 min late1,035

Every departure listed carries at least 600 operations, so the comparison is between figures that mean something. UA1233 is placed in the same ordering rather than left out of it; the rows around it are the most punctual departures on the route, not all of them, so this is a comparison and not a rank. Schedules change; confirm the departure still operates before booking around this.

Data and methodology

Calculated by FlyerIntel from 707 records of UA1233 operating DEN → EWR, published by the US DOT Bureau of Transportation Statistics. A flight counts as delayed when it arrives 15 or more minutes after schedule. Cancelled and diverted flights are excluded from the on-time rate and reported separately. Flight numbers are resolved as carrier plus number plus route, because the same number serves different routes over time.

Full methodology · Data sources · Report a problem

Related research: Most and Least Reliable Flight Numbers · The Delay You Inherit · Making Up Time in the Air

Analysis last recomputed