The short answer
Based on available data, the BMW X3 comes out ahead of the BMW X4 on fuel economy and power. Check the specs table and owner sentiment below for the full comparison before deciding between the two. Both are covered by real owner reports on CarWizz.
Overall
Sentiment is sharply divided and heavily dependent on model year, powertrain, and ownership phase. For newer models (approximately 2018-2024), owner feedback is generally positive, praising the X3 as a well-rounded, sporty luxury SUV with excellent driving dynamics, comfortable seats, good fuel economy for its class (low 30s MPG for the turbo 4-cylinder), and a high-quality, quiet interior. The B58 inline-six engine (in M40i models) is frequently highlighted as a standout for its power and reliability.
Best version to buy
The X3 M40i with the B58 turbocharged inline-six engine is the most recommended version for those seeking performance and reliability. For the four-cylinder models, the xDrive30i (all-wheel drive) is preferred over the sDrive (rear-wheel drive) for its all-weather capability and resale value.
Known issues
Overall
Mixed sentiment with a clear divide based on model variant and owner priorities. The X4 M40i and full M models receive strong praise for their powerful and reliable B58/S58 engines, engaging sporty handling, and overall driving enjoyment, with some owners describing them as the best cars they've driven. The coupe-SUV styling is polarizing, appreciated by some for its sporty, attention-grabbing look but criticized by others as an awkward compromise that sacrifices utility.
Best version to buy
X4 M40i: This model is frequently highlighted as offering the best balance, delivering the powerful and well-regarded B58 inline-six engine for strong performance without the extreme cost and ride harshness of the full M models. It provides a significant power upgrade over the base xDrive30i, making it the recommended choice for owners seeking a fun daily driver.
Known issues
The verdict
The BMW X3 is the better choice for most buyers.
It has better fuel economy on its best-equipped version than the BMW X4, based on the data above. If power matters more to you than running costs, the BMW X4 is worth a closer look instead.
Other comparisons
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Which is more reliable, the BMW X3 or the BMW X4?
Owner reports show similar reliability sentiment for the BMW X3 and the BMW X4. Check the known issues listed above for specific differences between the two.
Which is better for families, the BMW X3 or the BMW X4?
Both seat a similar number of passengers based on our data. The BMW X3 is classed as a SAV, the BMW X4 as a SAC, which affects cargo space and ride height for family use.
Which has better fuel economy, the BMW X3 or the BMW X4?
The BMW X3 is more fuel-efficient on paper: 7.7-8.3 L/100km combined versus 10.2 L/100km for the BMW X4, based on the best-equipped catalogued version of each.
Which is cheaper to maintain, the BMW X3 or the BMW X4?
Exact maintenance costs aren't in our data, but owner reports mention cost-related concerns more often for the BMW X3 than the BMW X4. See the known issues comparison above.