Date: 202001
Local time of day: 1201-1800
Location: RSW.Airport, FL
Flight conditions: VMC
Aircraft: Large Transport
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Takeoff / Launch
Airspace: Class C RSW
ATC / advisory: Tower RSW
Reporter organization: Air Carrier
Reporter function: Captain; Pilot Not Flying
Reporter qualification: Flight Crew Air Transport Pilot (ATP); Flight Crew Multiengine; Flight Crew Instrument
Human factors: Confusion; Workload; Distraction; Situational Awareness
Anomaly: Deviation / Discrepancy - Procedural FAR; Deviation / Discrepancy - Procedural Published Material / Policy; Deviation / Discrepancy - Procedural Weight And Balance; Inflight Event / Encounter Fuel Issue
Detector: Person Flight Crew
When detected: In-flight
Contributing factors: Company Policy; Human Factors; Weather; Procedure; Manuals
Primary problem: Human Factors

Narrative: Prior to boarding; I contacted Dispatch and discussed possible delays due to impending weather at the departure airport. I was aware that we would be waiting on the ground for weather to pass at the departure airport but we both expected that to quickly move through. Although the weather moved through quickly; once we taxied in line at approximately number 16; we were advised of 30 miles in trail for departures; meaning we would incur a significant delay. As we waited in line; the First Officer and I discussed the fuel and reviewed the weather enroute while also being aware of potential delay concerns. We also reviewed the weather forecast again and still noted that; should it become an issue; the alternate that was filed was not required and could be removed if necessary. I also sent an ACARs to Dispatch to verify that removing the alternate was an option and asked for them to review any changes so I could be aware as to whether or not removing the alternate was one way to manage the available fuel for planning purposes.After a taxi out time of approximately 1hr 30 minutes; we were number 1 for departure and verified that the fuel was above Min. Takeoff for departure. We had approximately 800 lbs. above what was required for Min. Takeoff. Just as we expected a takeoff clearance; Tower then informed us of a ground stop and had no idea how long it would last. We shut down both engines immediately to conserve the fuel for a quick restart and subsequent takeoff. With both engines shut down; the parking brake set; I spoke with the lead Flight Attendant to inform them of the ground stop and we coordinated that they would do a LOB delay service as well as give people an opportunity to use the restroom if necessary. I then called Dispatch to coordinate with them. We discussed the ATC issue; possible length of the delay; fuel state and the option to remove the alternate to fuel planning. I opted to keep the alternate on the paperwork only because; since we had the required fuel but still didn't know the time remaining on the delay; I didn't want to start with multiple changes to flight plan at this point so that we didn't create more work for us than necessary just yet. I also didn't want to have to change it back again if the weather deteriorated for some reason. While I was speaking with Dispatch and just after the ground stop was issued; the First Officer said they just lifted the ground stop and we're number one for takeoff. I remember noting the fuel at approximately 23.2 and the First Officer started both engines while I coordinated to ensure the passengers were seated and informed the Flight Attendants to stop their service for an immediate departure. The checklists were completed and I had one or two more calls to the Flight Attendant to ensure that the passengers and Flight Attendants were safely seated. We were cleared to 'Line up and Wait' and I noted the fuel at 22.8; above our Min. Takeoff of 22.6. After taxiing into position; we stopped for ATC to get spacing or traffic to clear but then we were cleared for takeoff.After climbing through 10;000 ft.; I requested the [Dispatch report] and started my review of that as we passed the first few fixes. I noticed that the fuel on takeoff on the [report] said 21.8; which immediately caught my attention because it was below the Min. Takeoff I was watching on the ground. I was surprised to see 21.8 on the [report] and immediately ACARS Dispatch and asked them to remove the alternate since the weather at the destination did not require it. They removed the alternate and sent me Release 2; which had a Planned Gate Fuel of 18.8 and a Min. Takeoff 17.5. This ensured our updated plan allowed us plenty of fuel for regulatory requirements and extra for altitude flex and turbulence mitigation. I informed the First Officer that the [report] showed we took off with 21.8 and we debriefed the error. Since I believe the [report] snapshot is taken at thrust lever application; I believe the error was mine. I'm certain that neither of us would have taken off if we saw that we were below 22.6; especially since we discussed it. I can only think that; in the moment and with my concerns being divided between the aircraft; flight attendants; passengers; and impending takeoff; I must have misread the 21.8 as 22.8 when we started the takeoff. As soon as I realized I must have made a mistake; I remedied the paperwork with Dispatch and immediately ensured that we could safely and legally continue to our destination. Once we removed the alternate and ensure we were safe and legal to continue; we continued and landed safely at our destination.




Synopsis: Captain reported departing with less than minimum takeoff fuel.