RX 350 vs MDX: Fuel Cost Flips the Cheaper Pick

Our calculator puts the 2020 Acura MDX at $39,980 over five years and the 2020 Lexus RX 350 at $40,181. That is a $201 gap, or about $4 a month. The MDX is cheaper, barely.

But the gap hides a fight. The MDX costs $2,867 more in gas over those five years. The Lexus gives that back, and then some, through repairs ($2,154 more), insurance ($547 more) and depreciation ($367 more). If you only look at the pump, the Lexus wins. If you look at the whole bill, the Acura edges it.

The $201 gap is a tie with a tilt

Call it what it is: a draw. A $201 difference over 60 months is not a reason to buy anything. A single set of tires or one bad month of gas prices could erase it.

What matters is the shape of the gap. Maintenance is identical at $6,490 each, and so is registration at $255. Those two lines cancel out. Everything else is a trade.

Here is how the trades stack up for the Lexus RX 350 against the Acura MDX:

• Fuel: the Lexus saves $2,867.
• Repairs: the Acura saves $2,154.
• Insurance: the Acura saves $547.
• Depreciation: the Acura saves $367.

The Lexus wins one category by a lot. The Acura wins three, each by less. Add them up and the Acura finishes ahead by $201.

That tells you the Lexus is not the bargain its reputation suggests. Buyers pay extra for the badge, and in this comparison they get back almost nothing in running costs except at the gas station.

Fuel is the Lexus's one big win

Our calculator has the MDX at $259 a month for fuel and the RX 350 at $211. That is $48 more every month for the Acura, and it never goes away. Over five years the MDX burns $15,555 in gas against $12,688 for the Lexus.

Fuel is also the largest single line for both cars. It is bigger than insurance, bigger than depreciation, and about three times what you will spend on maintenance in an average year. People shop on sticker price and ignore it. That is a mistake.

The yearly figures climb a little for both cars as fuel prices rise in our model. The Lexus goes from $2,438 in year one to $2,639 in year five. The MDX goes from $2,989 to $3,235. The $48 monthly gap stays close to steady.

If you want the official MPG ratings, check the 2020 Lexus RX 350 on fueleconomy.gov and the 2020 Acura MDX on fueleconomy.gov. Look up the exact trim you are considering, since all-wheel drive versions can differ. Your own mileage will move these numbers. Someone who drives far more than a typical owner will feel that $48 growing. Someone who drives little will barely notice it.

Repairs: where the Lexus gives the money back

This is the part that surprised us. Lexus has a reputation for being bulletproof. Our calculator says the RX 350 will cost $4,860 in repairs over five years. The MDX comes in at $2,706.

That is a $2,154 difference, and it grows every year. The Lexus starts at $540 in year one and reaches $1,530 in year five. The Acura starts at $301 and reaches $852. In year five, the Lexus costs $678 more in repairs alone.

Both cars are in the age range where warranties run out and parts start wearing. At 60,000 to 90,000 miles you are past the easy years. Brakes, suspension parts, sensors, and cooling components all begin to show up on invoices.

For reliability ratings, RepairPal publishes average annual repair costs and how often owners visit a shop for unscheduled work. Check both models there before you buy. We would not read a good RepairPal score as a promise that your specific car is clean. A neglected RX 350 is still a neglected car.

Our read: the Lexus is more likely to hand you a repair bill that stings, and the Acura is less likely to. The data does not say the Lexus is unreliable. It says it is not meaningfully better, and in our model it is worse. Lexus owners who assume the badge buys immunity are the ones who get surprised.

Year by year: the Lexus starts cheaper in Year 2 and fades

The two cars trade the lead depending on the year. Our calculator's yearly totals look like this:

• Year 1: Lexus $7,026, Acura $7,313. The Lexus is $287 cheaper.
• Year 2: Lexus $7,591, Acura $7,695. The Lexus is $104 cheaper.
• Year 3: Lexus $9,302, Acura $9,243. The Acura is $59 cheaper.
• Year 4: Lexus $8,476, Acura $8,277. The Acura is $199 cheaper.
• Year 5: Lexus $7,786, Acura $7,452. The Acura is $334 cheaper.

The Lexus leads for the first two years, mainly because of fuel. Then the repair line catches up with it. From year three on, the Acura is cheaper every single year, and the margin widens.

That pattern matters if you plan to sell early. Own the Lexus for two years and it is the cheaper car. Keep it to year five and the Acura pulls ahead. Our five-year total reflects a long hold, which is why the Acura wins.

Year three is the ugly one for both cars. Maintenance spikes to $2,653 for each, up from $1,072 the year before. That is likely a major service interval. Plan for it. Whichever car you buy, set aside money for that year, because it is $9,302 for the Lexus and $9,243 for the Acura.

The purchase price and depreciation

Our assumed purchase prices are $25,000 for the Lexus and $21,800 for the Acura. These are our estimates for this model year, and real listings vary with mileage, trim, and condition.

That $3,200 gap in price is real money, and the Lexus does not earn it back. It loses $5,662 in value over five years. The Acura loses $5,295. The Lexus holds its value in percentage terms about the same, but it has more to lose in dollars, so you absorb $367 more.

The Acura does take a bigger hit up front, with $1,344 of depreciation in year one against $1,258 for the Lexus. After that it slows down quicker. By year five the Acura loses $869 and the Lexus $1,018.

Insurance is a small edge for Acura

Our insurance figures are estimates based on each car's value and class. They are not quotes. Your own rate will differ based on your age, record, location, and insurer.

With that said, the calculator puts the Lexus at $10,226 over five years and the Acura at $9,679. That is $547 in the Acura's favor. It follows from the Lexus costing more to buy. Get real quotes on both cars before you decide, since this line can move the answer more than the $201 gap does.

The verdict

Buy the Acura MDX if you keep cars a long time and drive a normal amount. The MDX is cheaper to buy, cheaper to insure, and cheaper to fix. Those savings build year after year, and by year five it is $334 ahead for that year alone. You pay for it at the pump, so it suits someone who does not rack up huge mileage. Treat the $201 lead as a tiebreaker, not a prize. The better reason to choose the MDX is the lower repair risk and the $3,200 lower purchase price.

Buy the Lexus RX 350 if you drive a lot, or plan to sell within two or three years. The $48 monthly fuel savings is the only major advantage it has, and it matters most to commuters. If you will sell before the repair bills pile up, the Lexus is the cheaper choice through year two. You are also paying for the badge and the way the car feels, and that is a legitimate reason to pick it. Just do not tell yourself it is the thrifty option.

If neither of those describes you, pick the MDX. On our numbers it is the safer financial bet.