Flight Connection Risk Estimator
Use our free Flight connection risk tool to get instant, accurate results. Powered by proven algorithms with clear explanations.
Formula
P(success) = CDF((layover - MCT - delay) / std_dev)
Success probability is calculated using a normal distribution where the mean is the expected delay and standard deviation models delay variability. The layover must exceed the minimum connection time (MCT) plus expected delay for a positive buffer. The CDF converts the z-score into a probability percentage.
Frequently Asked Questions
What is the minimum safe connection time for flights?
Minimum connection times vary significantly by airport. Small regional airports may only need 30-45 minutes since gates are close together. Large domestic hubs like Atlanta, Denver, or Dallas typically require 60-90 minutes minimum. International connections at mega-hubs like London Heathrow, Dubai, or Tokyo Narita often need 90-120 minutes due to immigration, customs, and long terminal walks. Airlines publish their own minimum connection times (MCT), but these represent the absolute minimum with no margin for delays. Adding 30-60 minutes beyond the MCT provides a comfortable buffer.
How does time of day affect flight delay probability?
Flight delays compound throughout the day in what is known as delay propagation. Morning flights (before 9 AM) have the lowest delay rates because aircraft have been sitting overnight and are ready to depart. By afternoon, delays accumulate as each delayed departure pushes back subsequent flights using that aircraft. Evening flights (after 5 PM) experience 40-60% more delays than morning flights on average. Red-eye flights (departing after 10 PM) see a slight improvement as airport congestion decreases. For connections, booking the first flight of the day significantly reduces your risk.
Does having to change terminals significantly increase missed connection risk?
Yes, terminal changes are one of the biggest risk factors for missed connections. In many large airports, changing terminals requires taking a shuttle bus or train, passing through additional security, and walking long distances. At airports like JFK, moving between terminals can take 30-45 minutes. Even at airports with inter-terminal trains like Atlanta or Denver, allow an extra 15-20 minutes. International to domestic terminal changes are especially risky because you may need to clear customs and re-check bags. Flight Connection Risk Estimator adds 20 minutes to the minimum connection time when a terminal change is required.
What happens if I miss my connection due to delays?
If both flights are on the same booking (same reservation), the airline is obligated to rebook you on the next available flight at no charge. They may also provide meal vouchers or hotel accommodation for overnight delays. However, if flights are on separate bookings, you are fully responsible for rebooking and any additional costs. The average cost of a missed connection ranges from $150-$450 depending on route and time to next available flight. Travel insurance can help cover these costs. Always book connections on a single ticket when possible for maximum protection.
Is my data stored or sent to a server?
No. All calculations run entirely in your browser using JavaScript. No data you enter is ever transmitted to any server or stored anywhere. Your inputs remain completely private.
Is Flight Connection Risk Estimator free to use?
Yes, completely free with no sign-up required. All calculators on NovaCalculator are free to use without registration, subscription, or payment.