Your mileage may vary, and I’m pretty serious about that point.
At what point you should redeem your miles? Well, a little math never hurt anyone. There are a couple of things that you should know: how many miles you would earn if you paid for the flight and how many miles it takes to redeem that trip.
This formula comes courtesy of some timeless advice from Epinions user jeautk01. Let’s say you’re going to earn 1,924 miles between Chicago O’Hare and Houston International roundtrip. Likewise, it would cost you 25,000 miles to fly the same route. Adding the two numbers together, the total cost of your trip would be 26,924 miles. That number then needs to be multiplied against the worth of a frequent flyer mile, at 1.4 cents.*
When we finish that equation, we arrive at $376.93. That mean if the flight costs less than that amount, you should just buy it. If it costs more, redeem it.
The basic formula looks something like this:
[mileage to redeem ticket + mileage earned on a paid ticket] x [value of a mile]
[mileage to redeem ticket + mileage earned on a paid ticket] x .0014
The number you arrive will be the marker price that will help you distinguish whether a flight is a good deal or not. If it’s higher than what you get, it might be wise to cash in those miles.
Of course, this is a good basic rule of thumb for most redemptions and doesn’t include every scenario. If you’re travel-obsessed, it may be worth looking into this guide composed by Milevalue. How deep do you want to go?
*Back in the day, a frequent flyer mile was traditionally valued at 2 cents per mile. That has pretty much devalued over the years. Taking the value of a standard coach ticket (about $350, according to ABC News) and the required 25,000 miles to redeem one, a mile seems to be valued at about 1.4 cents these days. Some people argue it’s even lower at 1.2 cents, but let’s take it at 1.4 to give some room for error in each direction.