Your trip
65 US airports across all major metros.
41 destinations grouped by region.
Fill in your trip — we'll show which booking window saves the most.
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How we got these numbers
Domestic and international booking windows come from Google's 2021-2025 flight pricing study and Expedia's 2026 Air Hacks for Six report. Holiday windows come from Expedia's holiday travel breakdown and Going.com's 2026 fare trend data. Penalty ranges (10% early premium, 35% late-booking premium, 13% in-window savings) reflect average deviations in the same public datasets.
The booking curve, not a price color
Type the fare on your screen. The result scales that number onto three places: too early, inside the window, and too late. It does not tell you whether tomorrow is red or green.
| Trip | Window this page uses | What a prediction app often does instead |
|---|---|---|
| US domestic | About 15–30 days out (Expedia 2026 Air Hacks) | A wait badge any time its history says the fare has been lower |
| Europe | About 2–5 months, not the domestic curve | The same domestic rule, applied to a long-haul ticket |
| Mexico and the Caribbean | About 35–80 days | A color that ignores hurricane-season fare patterns |
| Hawaii | About 60–90 days | A last-minute “deal” that is the late premium |
| Thanksgiving / Christmas | Tighter, about 45–70 days, not “30 days for everything” | A generic sweet spot that is already late for the holiday |
Hotels can follow a different window. Refundable rooms can wait until the flight is locked. This is not a live fare search.
When to Book — Common Questions
How far in advance should I book flights?
The sweet spot for domestic flights is 3 to 5 weeks out, based on 2026 ARC and Hopper data. For international, book 2 to 6 months ahead. Holiday windows in this calculator are tighter than a normal domestic trip: Thanksgiving is 21 to 60 days out and Christmas is 36 to 72 days out. Google’s October 5, 2026 Flights analysis puts the Christmas low at 56 days before departure, inside a 33 to 67 day range. The worked example is the October 27 flight math.
Do flight prices go down closer to the departure date?
Generally no. Last-minute prices are higher, not lower, except for rare distressed-inventory sales. Prices typically dip in the 3–5 week window and then rise again. The calculator tells you whether you are inside the sweet spot or outside it for your specific travel date.
What is the cheapest day to book flights?
Day of week matters less than booking window. Tuesdays and Wednesdays occasionally show small discounts — typically under 5% — as airlines adjust pricing. The booking window (days before departure) has a much larger effect on price than what day you book.
When is the best time to book a cruise?
Cruises follow a different curve. Best prices are either very early (12–18 months out, especially during Wave Season January–March) or last-minute (within 30 days of sailing, with limited cabin choice). This calculator focuses on flights, but the same principles apply to cruise add-on airfare.