What if I told you that having a United credit card could mean the difference between paying 295,000 miles or just 72,000 miles for the exact same international business-class flight?

That’s not a rare or theoretical example. It’s a real award flight that a friend of mine was trying to book recently.

And while United’s credit cards are currently offering welcome bonuses of up to 100,000 miles, there’s another benefit that can be even more valuable long-term: Access to expanded saver award availability and dramatically lower award prices for eligible cardholders.

In fact, on some flights, the savings can quite literally be hundreds of thousands of miles per ticket.

Here’s how it works — and why having a United credit card can make such a huge difference when it’s time to redeem your miles.

Save hundreds of thousands of miles on flights

A friend of mine was recently searching for business-class award flights from Geneva Airport (GVA) to Newark Liberty International Airport (EWR) for a trip next month. He knew United cardholders could access lower award prices, but he didn’t have a United card, so he asked me to compare what we were seeing before deciding whether to apply.

As a non-cardholder, he was seeing business-class prices of 295,000 United miles per person, plus taxes and fees for the one-way trip from Geneva to Newark. That’s a lot of miles when multiplied out for a family.

As a cardholder, I checked the same flights and saw a much lower price.

For the same business-class flights, my price was just 68,000 miles per person, plus taxes and fees.

That’s 77% fewer miles for the same lie-flat seat on the same plane.

Now, I have United elite status in addition to a United credit card, which brings my award price down a little further. But even without elite status, someone with an eligible United credit card could book that flight for just 72,000 miles. That’s a savings of 223,000 miles on a single one-way ticket.

Here’s why the difference is so dramatic: The savings aren’t simply the result of a 10% cardholder discount. Eligible United cardholders can also access expanded saver award availability, which can unlock significantly lower award prices on certain flights.

And this isn’t just one route or one date.

I also searched for business-class award flights from my home airport of George Bush Intercontinental Airport (IAH) in Houston to Sydney Airport (SYD) and quickly found a flight priced at 400,000 miles for someone without a United card.

The cardmember-only price? Just 85,000 miles, plus taxes and fees. That’s a savings of 315,000 miles — or nearly 79% — on a single award ticket. Multiply it out by a family, and it gets even more incredible in a hurry.

Related: What it’s like in United’s new elevated business class

Eligible United cardholders can save at least 10% on award flights

While lots of United award flights have really big savings like the examples above, not every flight will offer discounts that dramatic.

You’ll always save at least 10% off qualifying United-operated award flights just by having a United card. That number jumps to at least 15% if you also have United elite status.

So, to give another real-world example, my family flies several times a year between George Bush Intercontinental Airport (IAH) in Houston and Orlando International Airport (MCO).

On this example date, one-way flights were priced at either 15,000 or 21,000 United miles, depending on which flight I selected.

However, because I have the United card, those flights were priced at 12,700 miles instead of 15,000 miles, or 17,800 miles instead of 21,000 miles.

Those savings aren’t as headline-grabbing as the first example, but for a family of four booking round-trip flights at those rates, the savings could add up to roughly 18,000 to 26,000 miles, depending on the flights selected.

Related: United’s big mileage changes are now in effect

Even the no-annual-fee United cards can activate the savings

One thing I really love about this is that you don’t need a premium United card with a high annual fee to unlock these award savings.

You can get the $0 annual fee United Gateway℠ Card (see rates and fees) and get savings, too.

If you have the United MileagePlus® Debit Rewards card or the $0 annual fee United credit card, you do have to spend $10,000 in eligible purchases on those cards in a calendar year to unlock the award discount.

For travelers who can meet that threshold through purchases they’d make anyway, the Gateway could provide a way to access lower award prices without paying an annual fee.

Another option is the United℠ Explorer Card (see rates and fees), which actually has a $0 introductory annual fee for the first year, then $150 annually. Eligible Explorer cardholders can access the award discounts without meeting the Gateway’s $10,000 spending requirement.

The information for the United MileagePlus Debit Rewards has been collected independently by The Points Guy. The card details on this page have not been reviewed or provided by the card issuer.

Related: 8 reasons to upgrade from the United Explorer Card to the United Quest Card

Get up to 100,000 bonus United miles to use for award travel with increased offers

Beyond the ongoing award-booking savings, United’s credit cards currently offer increased welcome bonuses, including some of the highest offers we’ve seen on these cards.

• United Club℠ Card (see rates and fees): Earn up to 100,000 bonus miles: Earn 90,000 bonus miles after spending $5,000 on purchases in the first three months from account opening. Plus, earn an additional 10,000 bonus miles after adding an authorized user in the first three months from account opening.
• United Quest℠ Card (see rates and fees): Earn up to 90,000 bonus miles and 500 PQPs: Earn 500 PQPs after your first purchase and 80,000 bonus miles after spending $4,000 on purchases in the first three months from account opening. Plus, earn 10,000 bonus miles after adding an authorized user in the first three months from account opening.
• United Explorer Card: Earn up to 80,000 bonus miles: Earn 70,000 bonus miles after spending $3,000 on purchases in the first three months from account opening. Plus, earn 10,000 bonus miles after adding an authorized user in the first three months from account opening.
• United Gateway Card: Earn up to 50,000 bonus miles: Earn 40,000 bonus miles after spending $1,000 on purchases in the first three months from account opening. Plus, earn 10,000 bonus miles after adding an authorized user in the first three months from account opening.
• United℠ Business Card (see rates and fees): Earn up to 100,000 bonus miles and 2,000 PQPs: Earn 90,000 bonus miles and 2,000 PQPs after spending $5,000 on purchases in the first three months from account opening. Plus, earn 10,000 bonus miles after adding an authorized user in the first three months from account opening.
• United Club℠ Business Card: Earn up to 100,000 bonus miles and 2,000 PQPs: Earn 90,000 bonus miles and 2,000 PQPs after spending $5,000 on purchases in the first three months from account opening. Plus, earn 10,000 bonus miles after adding an authorized user in the first three months from account opening.

The information for the United Club Business has been collected independently by The Points Guy. The card details on this page have not been reviewed or provided by the card issuer.

Bottom line

United credit cards can offer more than bonus miles and travel perks. For eligible cardholders, access to expanded saver award availability and discounts on qualifying award flights can translate into substantial savings when redeeming MileagePlus miles.

Being able to save airline miles with a co-branded airline credit card isn’t unique to United, as several airlines offer this valuable perk to their cardholders. However, the mileage savings you get with most cards and airlines are often capped at around 15%.

As the Geneva–Newark and Houston–Sydney examples show, the difference can sometimes amount to hundreds of thousands of miles on a single ticket. However, savings vary by flight, and not every cardholder automatically qualifies for these benefits.

Being able to take a lie-flat seat across the globe and make it cost in the neighborhood of 70,000-85,000 miles instead of 300,000-400,000 miles, just by having a credit card is exactly the kind of tip that brings award travel out of just the hands of a small few and puts it into the hands of many of us.

For travelers who regularly redeem United miles, these award-booking advantages could be among the most valuable reasons to carry an eligible United card.

Related: Which United credit card is right for you? Comparing the Explorer, Quest, Club and Business cards