Though they are similar-sized compact SUVs, there is an entirely different picture when comparing the Kia Sonet with the Mahindra XUV300 models in 2026. While the Sonet continues to be sold with all the petrol, turbo-petrol, and diesel engines, the XUV300 was discontinued in 2024 and replaced by the Mahindra XUV 3XO. Hence, buyers who plan on purchasing either of them today are actually comparing a new Sonet with a used XUV300.
Mileage is also more nuanced than the official figures suggest. The XUV300 petrol manual carried a slightly lower or comparable claimed figure depending on the Sonet powertrain, but the Sonet diesel manual is rated at 24.1 km/l and has also performed strongly in real-world tests. The XUV300 counters with substantially more torque, especially in diesel form, so the better choice depends on whether fuel economy or stronger performance matters more.
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Kia Sonet vs Mahindra XUV300 Specs
At present, the Kia Sonet offers three engine options: a 1.2-litre naturally aspirated petrol engine with 88 hp and 115 Nm of torque, a 1.0-litre turbo-petrol engine with 120 hp and 172 Nm of torque, and a 1.5-litre diesel engine with 116 hp and 250 Nm of torque. Depending on the engine, one can have the option of using a 5-speed manual transmission, a 6-speed manual transmission, a 6-speed iMT, a 7-speed DCT, or a 6-speed torque-converter automatic transmission.
The final Mahindra XUV 300 had a 1.2-litre turbo-petrol producing around 110hp and 200Nm, a stronger TGDi petrol producing around 130hp and 230Nm, and a 1.5-litre diesel producing about 117hp and 300Nm. Its diesel therefore had a sizeable 50Nm torque advantage over the Sonet diesel.
| Specification | Kia Sonet | Mahindra XUV300 |
| Petrol engines | 1.2L NA / 1.0L turbo | 1.2L turbo / 1.2L TGDi |
| Petrol output | 83PS, 115Nm / 120PS, 172 Nm | ~110PS, 200Nm / ~130hp, 230Nm |
| Diesel engine | 1.5L turbo-diesel | 1.5L turbo-diesel |
| Diesel output | 116hp / 250Nm | ~117hp / 300Nm |
| Transmissions | MT / iMT / DCT / AT | MT / AMT |
| Fuel tank | 45 litres | 42 litres |
| Current status | On sale new | Discontinued |
The XUV300 indeed beats the Sonet on torque figures, but the Sonet has more transmission options available and is still available as a new vehicle.
Also Read: Used Mahindra XUV300 Variants Guide: Choose the Best Variant
Kia Sonet vs Mahindra XUV300 Claimed Mileage
The Sonet’s standout official figure belongs to the diesel manual, which is rated at 24.1 km/l. The diesel automatic is rated at 18.6 km/l, the 1.2 petrol manual at 18.8 km/l, and the 1.0 turbo-petrol DCT at 18.7 km/l.
The last recorded figures of the XUV300 were as follows: 18.24 km/l for petrol manual transmission, around 17 km/l for petrol automatic transmission, 20.1 km/l for diesel manual transmission, and approximately 20 km/l for diesel automatic transmission. These figures should be taken as figures from the past, as the XUV300 is no longer produced as a new vehicle.
| Car | Powertrain | Claimed Mileage |
| Kia Sonet | 1.2 petrol MT | 18.8 km/l |
| Kia Sonet | 1.0 turbo DCT | 18.7 km/l |
| Kia Sonet | Diesel MT | 24.1 km/l |
| Kia Sonet | Diesel AT | 18.6 km/l |
| Mahindra XUV300 | Petrol MT | 18.24 km/l |
| Mahindra XUV300 | Petrol automatic | ~17 km/l |
| Mahindra XUV300 | Diesel MT | 20.1 km/l |
| Mahindra XUV300 | Diesel automatic | ~20 km/l |
On paper, the Sonet manual diesel comes with the best figure among the tests, while the petrol engines are comparatively close.
Also Explore: Kia Sonet Image Gallery: Interior and Exterior
Kia Sonet vs Mahindra XUV300 Real-World Diesel Mileage
Diesel provides the cleanest real-world comparison. In instrumented testing, the Sonet diesel manual returned 15.4 km/l in the city and 20.8 km/l on the highway. That gives a simple combined reference of around 18.1 km/l. The Sonet diesel automatic returned 13.8 km/l in the city and 18.8 km/l on the highway, averaging around 16.3 km/l.
The XUV300 diesel manual recorded 14.4 km/l of mileage while driving in the city and 17.9 km/l while driving on the highway,y providing a combined figure of nearly 16.15 km/l. Although the Mahindra had a stronger torque of 300 Nm compared to the Sonet diesel manual, the latter had a better fuel economy in the city and on highways.
| Sonet Diesel MT | XUV300 Diesel MT | |
| City mileage | 15.4 km/l | 14.4 km/l |
| Highway mileage | 20.8 km/l | 17.9 km/l |
| Combined reference | ~18.1 km/l | ~16.15 km/l |
| Fuel tank | 45L | 42L |
| Approx. mixed range | ~815 km | ~678 km |
Besides, the Sonet had an added advantage of having a three-litre larger fuel tank, allowing it to have a theoretical range of over 100 km more than the XUV300.
Kia Sonet vs Mahindra XUV300 Real-World Petrol Mileage
The petrol comparison is less direct because the available instrumented tests cover different transmissions. The Sonet 1.0 turbo DCT returned around 11.6 km/l in the city and 16.5 km/l on the highway, producing a simple combined figure of roughly 14.05 km/l. The turbo iMT recorded 11.2 km/l in the city and 15.8 km/l on the highway.
As far as the petrol versions are concerned, the standard XUV300 turbo-petrol manual returns approximately 9.7 km/l in the city and 14.8 km/l on the highway, giving a combined reference of around 12.25 km/l which shows that the Sonet has an advantage in the petrol tests, but this should not be considered a valid comparison as the transmission and the testing batches are different.
The XUV300’s petrol strength is performance. Even the regular turbo engine produced 200Nm, while the stronger TGDi version reached 230Nm. The Sonet turbo makes 172Nm, so its lower fuel use comes with less low-end torque.
Also Read: Mahindra XUV300 Alternatives: Competitors of Mahindra XUV300
Kia Sonet vs Mahindra XUV300 Fuel Cost Comparison
The diesel manuals give the maximum credibility of ownership-cost calculations, especially if we assume driving 1500 km every month, which is equal to 18,000 km annually, and diesel priced at ₹95.20 per litre in Delhi on 22 September 2026.
| Sonet Diesel MT | XUV300 Diesel MT | |
| Real-world reference | 18.1 km/l | 16.15 km/l |
| Monthly diesel use | ~82.9L | ~92.9L |
| Monthly fuel cost | ~₹7,890 | ~₹8,842 |
| Annual fuel cost | ~₹94,700 | ~₹1.06 lakh |
| 5-year fuel cost | ~₹4.73 lakh | ~₹5.31 lakh |
This means the Sonet diesel manual is approximately ₹950 cheaper than the XUV300 diesel manual on a monthly basis, resulting in total savings of around ₹11,400 annually and ₹57,000 over a period of five years at the same usage.
Petrol shows a similar direction. Using the available 14.05 km/l Sonet turbo-DCT reference and 12.25 km/l XUV300 petrol-manual reference, monthly fuel costs at Delhi petrol prices of ₹102.12 per litre would be roughly ₹10,900 and ₹12,500 respectively. Since those tests are not directly matched, the diesel comparison remains the stronger ownership-cost benchmark.
Kia Sonet vs Mahindra XUV300 Price
The Sonet is still available in 2026, and right now it has a starting price of ₹7.41 lakh ex-showroom. It comes with an asking price of up to ₹14.27 lakh depending on engine, transmission and trim. Kia also offers more variants now with automatic transmission, including its offered automatic version of the less expensive turbo petrol DCT and the diesel variants.
The XUV300 was discontinued in 2024. Its final recorded new-car price range was ₹7.99 lakh to ₹14.76 lakh ex-showroom. Those figures are historical only; a 2026 buyer will generally be looking at used examples whose prices depend on registration year, kilometres, condition, service history and variant.
| Model | Price Position |
| Kia Sonet | ₹7.41 lakh to ~₹14.27 lakh |
| Mahindra XUV300 | ₹7.99 lakh to ₹14.76 lakh* |
*Last recorded new-car prices before discontinuation.
One can save quite a bit by getting a pre-owned XUV300 as against purchasing the Sonet, so the fuel efficiency difference could turn less important.
Also Read: Kia Sonet Alternatives: Competitors of Kia Sonet
Summary
The Kia Sonet is the mileage winner overall, particularly in diesel-manual form. Its 24.1 km/l claimed figure is well ahead of the XUV300 diesel manual’s 20.1 km/l, while instrumented testing also favours the Sonet at around 18.1 km/l combined versus approximately 16.15 km/l for the Mahindra.
The XUV300 still manages to win over many buyers with its superior surface torque since it generates 300 Nm, which makes it a better performer compared to the Sonet with only 250Nm. The petrol engine used in the XUV300 also outperforms the Sonet in terms of surface torque, and it’s also a used vehicle, which naturally cuts down its price even further.
Overall, choose the Kia Sonet if mileage, longer driving range, multiple gearbox choices and buying a new car are the priorities. Consider the Mahindra XUV300 if you are shopping used and place greater importance on strong turbocharged performance and torque. For high-mileage diesel users, the Sonet manual is the clear efficiency choice.
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FAQs about Kia Sonet and Mahindra XUV300 Mileage
Q. Which has better mileage, Kia Sonet or Mahindra XUV300?
The Kia Sonet has better diesel mileage. Its diesel manual claims 24.1 km/l compared with 20.1 km/l for the XUV300 diesel manual.
Q. What is the real-world mileage of the Kia Sonet diesel?
The Sonet diesel manual has returned around 15.4 km/l in city driving and 20.8 km/l on highways, giving a combined reference of approximately 18.1 km/l.
Q. What is the real-world mileage of the Mahindra XUV300 diesel?
The XUV300 diesel manual returned around 14.4 km/l in the city and 17.9 km/l on highways, for a combined reference close to 16.15 km/l.
Q. Which is cheaper to run, Sonet diesel or XUV300 diesel?
At 1,500km per month and Delhi diesel prices of ₹95.20 per litre, the Sonet diesel manual costs around ₹7,890 per month compared with roughly ₹8,840 for the XUV300 diesel manual.
Q. Which has better petrol mileage?
Available real-world tests favour the Sonet turbo-petrol, but the comparison is not perfectly like-for-like. The Sonet turbo DCT returned around 14.05 km/l combined, while the tested XUV300 petrol manual returned about 12.25 km/l.
Q. Is the Mahindra XUV300 still available new?
No. The XUV300 was discontinued in 2024 and replaced by the Mahindra XUV 3XO. In 2026, the XUV300 is primarily a used-car purchase.
