Trip and fares

The first step fixes the trip: how many travelers, whether it is one-way or round trip, and each fare per traveler for the whole trip. The difference between the two fares is the sticker gap, the number the booking page advertises and the one the next steps either keep or erase.

Bags

Carry-ons and checked bags are counted by how many travelers bring each one, so a party with three bags among four people can enter exactly that, up to a third bag per traveler. Fees are entered per traveler and per direction, since airlines commonly charge them each way rather than once for every connecting flight, and the carry-on line is meant to include any gate charge because some Basic fares allow only a personal item.

Two travelers flying round trip see $238 on Basic and $298 on Main each, a $120 gap. If Basic charges $75 per direction for a full-size carry-on, Basic totals $776 against $596 for Main, and the $120 gap becomes $180 in Main’s favor.

Seats

Seats are priced only for the travelers who need to choose one. Each fare can have free seat selection, a fee per traveler and direction, or no selection at all. A fare that does not offer seat choice adds no dollars to the total, because an assigned seat has no price, and it is flagged separately since assigned seats may not put a group together.

If plans change

The last input is the amount you would lose on each fare if you had to change or cancel, after any refund, credit or change fee. It can be a share of the fare or a fixed total, since prepaid extras and travel credits do not follow a percentage. For tickets bought at least seven days before departure, U.S. rules require airlines to offer either a 24-hour hold or a 24-hour cancellation with a full refund, so the amount entered matters mostly after that window.

Result and break-even

The result shows what each fare costs if plans hold, a line-by-line account of how bags and seats changed the original gap, and how much more protection Main gives if plans change. With one $50 checked bag each way on both fares and $25 per seat per direction on Basic only, that $120 gap shrinks to $20, and Main comes out ahead once the chance of changing or canceling passes about 4%, assuming Basic would forfeit the whole fare and Main nothing.

The break-even chance is the point where both fares have the same expected cost for the amounts entered; it is not a forecast of your plans. The slider starts there, and moving it prices both fares at any other chance. When one fare is no worse at every chance from 0% to 100%, the slider is replaced by the two ends of that range.

Miles, status benefits, boarding priority, comfort and insurance are not priced.

Fees and fare rules vary by airline, route, ticket date and booking channel, so enter the amounts shown for your booking. The dollar figures in the examples above are illustrative. This tool uses no live fares, is not affiliated with any airline and is not travel or financial advice. The 24-hour rule is described in U.S. DOT guidance on buying a ticket, and it does not cover tickets booked through third-party agents. Last updated: September 2026.