How to get United Airlines upgrades using miles

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It's the dream of every frequent traveler to snag much-coveted space at the front of the cabin, but short of paying for first class yourself, your chances are always left up to fate. Well, almost always.

While elite members and holders of upgrade certificates alike can can hope that upgrades clear before takeoff, there's another way to potentially secure your seat long before you leave the ground. Using miles to upgrade paid flights can be a good way to use points — and in some cases, can get you some serious value. We'll show you how.

Which miles can you use?

The obvious answer here is that you can use United miles to upgrade your United flight. Of course, it can be difficult to acquire these miles if you're flying on low fares (like me), which acquire reward miles based on revenue rather than mileage flown. Luckily, if you have an annual-fee Chase Ultimate Rewards card, you can transfer Ultimate Rewards in at a 1:1 ratio to United. You can also transfer in points from Marriott at a 3:1.1 ratio, with a 5,000-point bonus for every 60,000 points you transfer.

How do you earn miles?

As mentioned above, it can be difficult to earn United miles based on actual flying, but there are tons of alternative ways to boost your balance:

• The Chase Sapphire Reserve has a current sign-up bonus of 60,000 points after you spend $4,000 on purchases in the first three months of account opening
• The Chase Sapphire Preferred Card has a current sign-up bonus of 100,000 bonus points after you spend $4,000 on purchases in the first three months of account opening
• The United Explorer Card has a current sign-up bonus of 50,000 miles after spending $3,000 on purchases in the first three months of account opening
• The United Explorer Business Card has a limited-time offer of up to 100,000 miles- 50,000 bonus miles after you spend $5,000 in purchases in the first 3 months your account is open plus, an additional 50,000 bonus miles after you spend $25,000 total in purchases in the first 6 months your account is open
• The United Club℠ Card has a current sign-up bonus of 50,000 miles after $3,000 in spend in the first 3 months

You can see there are tons of ways to acquire United miles with credit cards, but if you're not looking to apply or already have these cards, there's another way to build your balance. I used this method myself during a recent Tel Aviv (TLV)- San Francisco (SFO) flight to upgrade from economy to Polaris, and it's one of TPG staffer Zach Honig's favorite ways to buy United miles. Using award accelerator, I purchased miles at 2.0 cents each and applied them as a mileage upgrade (along with a co-pay) in order to secure my seat.

How many miles do you need?

The amount of miles you need in order to upgrade will depend on a number of factors, including your region of travel, fare class and Premier elite status. To see the rate that applies to you, visit the page with the interactive award chart and enter your origin and destination. As a MileagePlus Premier Platinum member, I've gone through and searched several different routes to compare the mileage it would cost me on both international and domestic routes:

Note that the yellow arrows indicate there's only waitlist available for upgrades, so if you purchase this fare and apply miles there's no guarantee your upgrade will clear.

The green arrows here mean that you can book your flight, pay the miles (and co-pay, if necessary), and immediately be confirmed into your new cabin.

As you can see, the amount of miles you'll need depends on the flight you're trying to book, from as few as 20k miles (though technically you should be able to find some as low as 7.5k) to as many as 35k.

What kind of upgrades can you get?

Depending on your flight, you may be able to book into either premium economy or business using your miles. As you can see from the examples above, the mileage cost will be the same (upgrading from an economy ticket), but the cash cost will differ according to your cabin. Business class on international flights will incur a copay, while premium economy will not.

In my case, I shelled out the $600 copay for my TLV-SFO flight in order to spend 14 hours in business class instead of premium economy. This made sense, as the cash cost to upgrade was $3,000, whereas miles bought with award accelerator cost just $700 (for 35k). Together with the copay, I ended up out of pocket $1200. I wouldn't have achieved this same value in premium economy.

Keep in mind, though, that if you upgrade with miles you'll still be credited in the cabin you originally paid for. This is not the case with cash upgrades, which credit your mileage based on the cabin you end up flying.

How to upgrade a United Airlines flight with miles

There are two types of ways use your miles to upgrade your flight. Before you buy your ticket, you can use advanced search in order to filter out flights that have immediate award availability:

If you've already bought your ticket, you can head to 'manage trip' on your United account, then hit 'upgrade cabin.' If there's availability to upgrade immediately, you'll be able to purchase and pay to change your seat. If not, you'll be shown a page like this, which'll put you on the waitlist for an upgrade:

If your upgrade doesn't clear, you'll be refunded what you've spent. It's also worth noting that, according to United's page, you can also use Mileage Upgrade Awards to upgrade yourself on all Star Alliance operated flights, not just United.

Is it worth upgrading with miles?

This is a difficult question, and entirely dependent on your preferences. 12.5k miles will get you a one way economy ticket across much of the U.S., so these upgrades aren't coming cheaply. However, if you find yourself on an ultra long-haul flight and not wanting to sit in the back of the cabin, this could be a way to score a premium seat without shelling out huge amounts of cash. That doesn't mean this is the best way to use your miles, though, as there are many different ways to maximize redemptions.

What are your upgrade chances?

If you don't book a flight that has immediate availability (which I would generally recommend, as long as your dates are flexible), there are a number of different factors that will affect your upgrade clearing, including:

• your fare class
• your MileagePlus elite status
• the popularity of the route (and the chances they'll release space)
• whether or not you're a United credit cardholder
• when you requested the upgrade

Bottom line

Whether or not you choose to upgrade your flight with miles is up to you; on shorter flights the mileage cost may not be worth it, but used correctly these upgrades can turn a long journey into a high-class affair. This is especially true if you've got a large balance of miles or plan to purchase them at a discounted rate. And don't forget- there are tons of ways to spend your miles for maximum value.

(Featured photo by Alberto Riva/The Points Guy.)