The Delta Air Lines loyalty program, SkyMiles, rewards frequent flyers with countless redemption options and booking bonuses like no blackout dates.

This airline’s four-tiered membership programs stacks on even more benefits for the most loyal members. Each of the tiers (silver, gold, platinum, and diamond) have many features and perks with the diamond level being the most exclusive and rewarding.

You can use miles you rack up to book Award Travel flights, upgrade your seats to a better class, cash in on freebies with Delta Sky Club, and more. 

Though Delta miles aren’t worth as much as frequent flyer miles you might earn with other carriers (1.1 cent per Delta SkyMile vs 1.3 cents per average airline mile) they can still save you money if you know what you’re doing.

Whether you’re earning miles by flying Delta or making purchases through Delta partners or with Delta American Express credit cards, there may be times in which you need just a few more miles to get what you’re looking for. In which case, purchasing miles might make sense.

That said, purchasing Delta SkyMiles through your SkyMiles account is going to cost you 3.5 cents per mile at retail price with no promotions going on, which is significantly more than they’re worth.

Keep reading for more information about when it makes sense—and when it definitely does not—to buy Delta SkyMiles with your cash.

When is it a Good Time to Buy Delta Skymiles With Cash?

While purchasing airline miles in general is almost always a bad idea, it does make sense in certain situations.

In general, purchasing Delta SkyMiles in one or more of the following three scenarios tends to make the most sense for most people:

When Buying SkyMiles to Get a Free Ticket

If you have enough miles stocked up, you might be able to pull off flying for free (or almost free). To find out the price in miles of any given flight, simply select “Shop with Miles” in the search engine through the Delta site or the Fly Delta app. 

A minimum of 5,000 miles is required in order to use your miles to book Award Travel, and redemptions must be made in 5,000-mile increments. If you see a great deal on a flight—say 10,000 or 15,000 round trip—and you are within just a few thousand miles of being able to get it, buying miles could be a sound investment.

If this is the case, only buy as many as you need. Delta will allow you to purchase as few as 2,000 miles at a time, but prices vary.

Key Takeaway: Make sure buying miles in order to get a free ticket won’t cost more than simply paying the difference with cash.

For example, imagine you’re trying to fly from Los Angeles to New York City and you already have 34,500 miles in your SkyMiles account. You then come across a ticket available for 36,000 miles – or – $460. You can either purchase the ticket without your miles for $460 cash or you can spend $70 to buy the minimum of 2,000 miles to top off the 1,500 you needed for your trip. In this scenario buying SkyMiles makes sense.

Two additional variables to keep in mind that could affect your bottom line cost are:

1. small fees are assessed for award redemption and
2. flights through partner airlines will have different Award Travel requirements.

When Buying SkyMiles to Upgrade Your Seat

Purchasing frequent flyer miles for seat upgrades is fairly common practice across all airlines, and this is true for Delta as well.

You’ll be able to upgrade your seat during or after booking using your miles balance for as many flights in your party as you want (just make sure there are enough award seats available).

If you value the added luxury of business or first class but don’t necessarily want to cough up the money for the considerable up-charges, using miles to upgrade is the way to go.

And if you don’t have quite enough miles to get that upgrade, then purchasing a few thousand to top it off may make sense.

The miles required to upgrade your seat is going to depend on where you’re going and when, but don’t expect purchasing the additional miles needed to be a cost-cutting option unless you already have a good portion of the miles required in your account.

When Buying Discounted SkyMiles

Another situation where purchasing Delta SkyMiles might make sense is when they offer special deals and promotions that drastically bring down the cost per mile.

Delta has been known to offer very competitive discounts on miles in the past. We’ve seen discounts run as high as 75% on miles, effectively reducing the cost of purchasing miles to roughly 1.75 cents per mile (vs 3.5 cents retail). This is still above the average value you receive per SkyMile (which sits at roughly 1.1 cent per mile) but it makes buying miles a much more attractive prospect, especially if you have a specific use in mind for them.

Buying these miles in large amounts when they go on sale likely isn’t the best idea without specific use cases for them. That said, if you’re very loyal to Delta and fly regularly it may be worth it to pick some up when the promotions take place and set them aside for future use.

When it is Not a Good Idea to Buy Delta Sky Miles

It’s never a good idea to purchase Delta flight miles when miles cost more than they are objectively worth. Here are a couple of things to watch out for when you’re considering whether or not to buy more miles.

When the Math Doesn’t Work

To know for sure if purchasing SkyMiles is a wise decision, you will need to put in a little extra work.

In a nut shell, make sure that the total price you pay purchasing the amount of miles needed for a trip is always less than what it would cost in cash.

Generally speaking purchasing lower increments 2,000 – 5,000 to top off an award is going to be the way to go. Here’s a table illustrating how expensive SkyMiles can get the more you purchase:

Cost of SkyMiles (assuming full retail price of 3.5 cents per mile):

Number of Miles	Cost to Purchase
2,000	$70
5,000	$175
10,000	$350
30,000	$1050
50,000	$1,750

When the Tickets You Wish to Buy Are Unavailable

Award seats are in short supply on most flights. If you’re considering buying miles for a particular flight or trip, make sure there are seats available ahead of time.

Sadly, not all flight seats can be purchased with miles, so you’ll need to plan as far in advance as possible if you intend to use miles to buy a ticket.

To check whether a flight has award seats available during booking, enter your desired flight information and select “Shop With Miles” or “Show Price in Miles.” If seats are available, you will see them and how much they cost. If there are no more seats available, you can try checking a different flight class to see if there are more there. 

Final Thoughts

To get the most out of your Delta SkyMiles, whether they are purchased or earned, you need to make sure you know what they’re worth. Purchasing miles is usually not a smart move, but a few scenarios (outlined above) make it potentially beneficial.

Visit the Delta SkyMiles Deals page for a complete list of advertised offers including the best-priced tickets available. Flash deals that maximize the value of your miles are updated monthly.

If you already have a sizable pool of miles in your account and you have a specific upgrade or trip in mind, then buying a few more to nab that offer may be a good way to travel cheaper.