All input fields below have an impact on the base pax load factor specified at the bottom. This is then used as the base (mu) for a beta distribution with a variance (sigma) further influenced by the input fields (some flights have more volatile bookings than others).
For additional cargo two different industry-wide averages for both pax+cargo and pure freighter flights are being used as the base for a similar beta distribution (adjusted by block time). (Longer flights = more cargo because more profitable, shorter flights = less cargo because shorter turnaround times)
Both can be further affected by rare random events. The result is a realistic and plausible, but still slightly random load factor for pax and cargo for the specific circumstances of that flight.
The calculations have been verified by unit tests over large sample sizes (10000 flights) to be mathematically correct and precise.
What to enter in Simbrief: Only enter the pax number and the total payload into Simbrief. Simbrief will automatically calculate the freight (and baggage) from it. The Simbrief cargo values will be different from those here, as depending on the Simbrief aircraft profile a different pax weight and baggage weight is applied (which is not a problem - the only operationally determining factor is the total payload value). We use our own pax and baggage weight calculations (true to real life dispatching) and they will reflect correctly in the total payload value.
Simbrief says I'm weight limited: If you're MZFW or MLW or MTOW or even performance limited - that's no problem, those are operational constraints. Just use the values as capped by Simbrief's automation. Consider this app calculating the specific "demand", independent of whether it's operationally possible for the specific weather, active runways, fuel needed etc.

Added copy to clipboard of most important infos (e.g. to copy into Simbrief text field)
Replace block time input by input in hours and minutes (for you Ginger ;)
Airline and airport ICAOs in lowercase do not cause an error anymore
Passenger numbers are now editable after the calculations (and payload will reflect any changes)
Offsets will now be calculated and entered automatically
Add general info field with some non-bonus/non-penalty infos
Extensive verification and validation of all internal backend calculations
Replaced regional demographic passenger weights with true-to-real-life regional regulator weights as required by local law (e.g. FAA, EASA etc.). For further info about current limiations read the ? in the Passenger Insights.
Added genders with appropriate weights to passenger calculations. True to real life legal dispatch values
Refining of MELs: Cabin / IFE items now have a higher chance + (ultra) low cost airline types have a much higher chance for MELs than other airline types
Add dark mode
Rework of labour route type

RYS, MAY, CYP, AWC (as type "Holiday" since it's a charter airline with very stable bookings), SWG, OCN, WTB, HKE, TGW, TVJ, TVS, TVQ, TVP, TVL, WUK, WMT, BKP, SJX, ROU (type "Holiday"), RUK, ZAP, AFL, OAW, JAF, FJL, JTD

MD11, MD1F, B75F, B76F, A346, A339, A310, B77L, B736, B733, B734, B735, MD82, MD83, MD88, DH8D, E290, E295, all BAE146 variants (incl. Avro RJs), all Fokker variants

Flight Data

Payload Calculation

Total Passengers:

Passenger Insights (click to expand)

Additional Cargo:

Total Payload:

Operational Restrictions

Times

Minimum Equipment List (MEL):

Cargo Content:

Other operational notes:

Simulation Impacts

Feedback & Bug Reporting

Realistic Pax & Cargo (RPC) - Flight Sim Payload Calculator

Flight Data

Suggest adding airline to database

Payload Calculation

Total Passengers:

Passenger Insights (click to expand)

Additional Cargo:

Total Payload:

Operational Restrictions

Times

Minimum Equipment List (MEL):

Cargo Content:

Other operational notes:

Simulation Impacts

Feedback & Bug Reporting