Flight number record
UA 512
United Airlines · Houston to Washington
- Route
- IAH → DCA
- Departs
- 07:30
- Flights
- 254
- Period
- July 2025 to June 2026
Historical statistics for July 2025 to June 2026, not live status. For today’s UA 512, check with United Airlines.
UA 512 earns an A. Nearly every flight arrives inside the 15-minute window the DOT uses to define an on-time arrival, which puts it 16 points better than the national rate of 77.6%. When something does go wrong the average delay runs about an hour. That rests on 254 flights, with a median arrival 11 minutes early.
Set against the rest of the country, UA 512's record is 16 points better than the US average of 77.6%. That gap is worth roughly 160 fewer late arrivals for every thousand flights.
Key figures
On time
93.6%
Arrivals under 15 minutes late, of 251 completed flights
Avg delay
66 min
Across delayed arrivals only, not all flights
Cancelled
1.18%
National rate is 1.81%
1 hour+ late
3.2%
National rate is 8.1%
These figures cover 254 flights between July 2025 and June 2026. The median arrival is 11 minutes early, which is the part an average hides: most flights here are fine, and the on-time rate is decided by a tail of badly late ones. On-time means under 15 minutes late, the DOT's own threshold.
Schedule
When UA 512 flies
UA 512 flies IAH to DCA without a single fixed slot. Its most common scheduled departure was 07:30, used on 123 of 254 flights, with 07:35 (115 flights) next. Carriers retime flights through the season, so the rates here blend slightly different positions in the aircraft's day.
- Departs 07:30123 flights48.4%
- Departs 07:35115 flights45.3%
Scale runs 0% to 100%. Rows with fewer than 30 flights show a dash.
Share of scheduled departures at each local time. Times used on fewer than one flight in ten are not listed.
A 07:30 departure sits in the 5am–8am window. Across every US flight scheduled in that window the on-time rate is 89.3%, and UA 512 runs 4 points better at 93.6%. Early departures usually start with an aircraft that has not flown yet that day, which is most of why the window does well.
Against the route
UA 512 next to IAH to DCA
Every carrier on IAH to DCA combined arrived on time 74.8% of the time across 3,202 flights, so UA 512 is 19 points ahead of it. United flew 2,413 flights on the same city pair under all its flight numbers, including this one, and those ran 75.2% on time. Across its whole network United Airlines managed 79.0%, which this flight beats by 15 points.
| Compared with | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| UA 512thin sample | 254 | 93.6% | 66 min | 1.18% | A |
| All United Airlines on IAH–DCA | 2,413 | 75.2% | 70 min | 0.79% | B+ |
| All carriers on IAH–DCA | 3,202 | 74.8% | 73 min | 1.81% | C |
| United Airlines, whole network | 821,041 | 79.0% | 72 min | 1.01% | B |
Across the year
UA 512 quarter by quarter
UA 512 did not run the same all year. Its best quarter was Jan–Mar 2026 at 97.7% on time and its weakest Jul–Sep 2025 at 83.3%, a swing of 14 points on roughly 64 flights a quarter. The twelve-month rate averages over that, so if you are flying in a weak quarter the quarter's own figure is the better guide.
- Jul–Sep 202549 flights83.3%
- Oct–Dec 202566 flights95.4%
- Jan–Mar 202689 flights97.7%
- Apr–Jun 202650 flights94.0%
Scale runs 75% to 100%. Rows with fewer than 30 flights show a dash.
By weekday, UA 512 ranged from 88.6% on Thursday to 100.0% on Wednesday. With about 36 flights behind each day, a spread of 11 points is inside normal variation, so the day you fly is not worth changing for this flight.
Delay causes
Why UA 512 runs late
One category carries most of the weight here. Carrier accounts for 45% of the 1,053 delay minutes carriers reported, and the remaining four split what is left. The split is by minutes rather than by flights, so a few very long delays count for as much as many short ones.
- 45%Carrier
- 29%Late-arriving aircraft
- 26%National Airspace System
The largest share of delay minutes, 45%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. Unlike weather, that is a management outcome, and it is the category where the gap between two carriers on the same schedule is genuinely earned. It accounts for 476 of the 1,053 delay minutes reported here. The split is drawn from 1,053 delay minutes reported on UA 512.
Cancellations sit at 1.18% against a national 1.81%, which is ordinary. Diversions add another 0.00%.
Connections and routes
What a delay on this flight costs
Badly late arrivals are rare here: only 3.2% land an hour or more behind schedule, against 8.1% nationally. Connections built on this flight are about as safe as US domestic connections get, though a cancelled flight still ignores every layover you give it.
The 1,208 miles between these two airports put this in the middle of the US network, around two and a half to three hours of block time. That is enough cruise to absorb a ten-minute late pushback and not enough to absorb thirty. It is also long enough that the aircraft usually flies three or four legs a day rather than six, which slows how fast delay compounds.
The same number turns up on four other city pairs in the data, including SFO to IAH (243), CID to ORD (35) and BOS to SFO (6), but none flew often enough under UA 512 to report a rate for. Carriers move flight numbers between routes, so the figures on this page apply to IAH to DCA only.
One caution: this is a thin sample. 254 flights over twelve months is enough to clear this site's floor but not enough to pin the rate down tightly, and a single bad week moves it by more than a point. Treat the grade as a rough reading.
What to do with this
Booking UA 512
For a booking, UA 512 has one of the better records a US domestic flight can show: 93.6% on time and 1.18% cancelled. That is a base rate, not a promise about any single day.
Related
Where to go next
- IAH to DCA, every carrier and departure
- DCA to IAH, the return direction
- United Airlines 1627 on the same route64.2%
- United Airlines 2224 on the same route69.8%
- United Airlines 2311 on the same route83.6%
- United Airlines 654 on the same route75.8%
- George Bush Intercontinental (IAH) delay statistics
- Ronald Reagan Washington National (DCA) delay statistics
- United Airlines on-time record
- Every United Airlines flight number with a record
- The most and least reliable flight numbers in the US
- Worst months to fly in the US, ranked by the data
A flight number here means United Airlines’s own number as it reports to the DOT. How the figures are computed is on the methodology page.
Source: US DOT Bureau of Transportation Statistics, on-time performance data, July 2025 to June 2026. Last updated 15 September 2026; recomputed monthly. How this data is collected.