SEAT Mii (2018)

Estimated running costs and MOT pass rates from 1,975 MOT tests in 2024.

Annual Cost

£1,780

£148/month

MOT Pass Rate

89%

Good

Road Tax

£200

Standard rate/year

Est. Insurance

Grp 1-8

999cc Petrol

Solid Option

89% pass rate, £1,780/year to run. 7 points above average.

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Petrol999cc8 years old1,975 tests34k miles avg

Annual Running Costs

Fuel (Petrol, 999cc)

~50 mpg

£1,175

Road Tax

Standard rate (from April 2017)

£200

MOT Test

£55

Predicted Repairs

£350

Total per year£1,780

Per month£148/mo

Per week£34/wk

Estimates based on 7,400 miles/year (UK average), petrol at 174.57p a litre (GOV.UK weekly average, week of 19 October 2026), GOV.UK road tax rates and repair likelihood from MOT data. Insurance not included. Cars registered from April 2017 pay the £200 standard rate, plus £440 a year for five years (from the second year) if they cost over £40,000 new (over £50,000 for electric cars).

Reliability Verdict

89% MOT pass rate(Good)

0%All-model avg: 82%100%

Good reliability. Occasional issues but generally solid. That's 7 points above the average of 82% across all models in our data. It also outperforms the SEAT brand average of 85%.

89% of MOT tests on SEAT Miis from 2018 ended in a pass in 2024, when they were about 6 years old. That's based on 1,975 tests across the UK, retests included. The average mileage recorded at those tests was 33,651 miles.

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How Does It Compare?

Rank among 2018 models379th of 607(bottom half)

Rank among SEAT models140th of 310(top half)

vs average of all models+7%(82% avg)

vs 2018 models average+0%(89% avg)

vs SEAT average+4%(85% avg)

Mileage Analysis

33,651

Average miles

44,400

Expected for age

The average 2018 SEAT Mii had 33,651 miles on the clock at its 2024 MOT, which is below the expected 44,400 miles for a 6-year-old car. This suggests lighter use than average, which generally means less wear on major components.

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Best Year to Buy?

Of the years with at least 100 tests, the 2019 model has the highest MOT pass rate at 93%, while the 2012 model has the lowest at 81%. The 2018 scores 89%. Newer cars usually pass more often simply because they are younger, so compare years of a similar age.

SEAT Mii by Year

Year	Pass Rate	Tests	Avg Mileage
2019	93%	1,976	27,272 mi
2018	89%	1,975	33,651 mi
2017	87%	2,338	39,917 mi
2016	86%	3,557	46,587 mi
2015	85%	4,201	52,581 mi
2014	84%	5,035	59,614 mi
2013	82%	5,782	66,168 mi
2012	81%	2,875	70,829 mi

Similar Cars to Consider

Ford Fiesta

2016 · 998cc Petrol

£1,600/year

81%

-8%

Vauxhall Corsa

2016 · 1398cc Petrol

£2,003/year

81%

-8%

Nissan Qashqai

2017 · 1200cc Petrol

£1,780/year

86%

-3%

Vauxhall Astra

2016 · 999cc Petrol

£1,600/year

85%

-4%

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About the 2018 SEAT Mii

The 2018 SEAT Mii is a city car. Our records list a 999cc petrol engine, though engines vary between versions. 1,975 MOT tests were recorded on this model in 2024, making it a reasonably common sight on UK roads. Among all models from 2018, the average MOT pass rate is 89%, and this model matches that benchmark.

With an average of 33,651 miles recorded at its 2024 MOT tests, SEAT Mii owners tend to use this car less than the typical driver.

2018 SEAT Mii Fuel Costs

The modest 999cc petrol engine keeps fuel costs low, which is a real advantage for a city car. Expect around 50 mpg in mixed driving, which works out to roughly £1,175 per year with petrol at 174.57p per litre (GOV.UK weekly average, week of 19 October 2026; based on 7,400 miles per year).

What does it cost to own a 2018 SEAT Mii?

Total estimated annual running cost is £1,780 (£148/month), broken down as £1,175 fuel, £200 road tax, £55 MOT, and £350 predicted repairs. Repair costs are moderate, reflecting the 89% pass rate. Keeping on top of servicing will help avoid surprises.

SEAT Mii Reliability Trend

Newer SEAT Miis pass their MOT more often than older ones, by 6 percentage points on average, which is mostly down to age and wear.

Buying a Used 2018 SEAT Mii

At 8 years old, this is a solid used buy if you find one with good service history. Depreciation has levelled off, so you won't lose much more value. Focus on condition over mileage. If you're flexible on year, the 2019 model has the highest pass rate at 93%.

Common Issues to Watch For

These are typical issues for cars of this age, fuel type and engine size, not faults recorded on this model's MOT tests. Use them as a checklist when you view one.

Coil Pack Failure

Medium risk

Smaller petrol engines are prone to ignition coil failures, causing misfires and rough running. Replacement is £50-£150 per coil.

Suspension Wear

Medium risk

Shock absorbers, springs, and anti-roll bar links typically need attention around this age. Listen for clunks over bumps and check for uneven tyre wear.

Service History

Low risk

Always request a full service history. Regular servicing is the single best indicator of how well a car has been maintained, regardless of mileage.

Running Costs Compared

How the 2018 SEAT Mii stacks up against similar cars for estimated annual running costs, insurance group, and tax.

Car	Pass Rate	Fuel/yr	Tax/yr	Est. Ins. Group	Total/yr
SEAT Mii(2018)	89%	£1,175	£200	Grp 1-8	£1,780
Ford Fiesta(2016)	81%	£1,175	£20	Grp 1-8	£1,600-£180
Vauxhall Corsa(2016)	81%	£1,398	£200	Grp 8-20	£2,003+£223
Nissan Qashqai(2017)	86%	£1,175	£200	Grp 5-15	£1,780same
Vauxhall Astra(2016)	85%	£1,175	£20	Grp 1-8	£1,600-£180

Estimates based on 7,400 miles/year, GOV.UK average pump prices for the week of 19 October 2026, GOV.UK road tax rates and MOT data. Insurance groups are our rough estimate from engine size, not official groups. Actual costs vary by driver, location, and usage.

Questions about the 2018 SEAT Mii

Is the 2018 SEAT Mii reliable?

Good reliability. Occasional issues but generally solid. 89% of MOT tests on 2018 SEAT Miis ended in a pass, from 1,975 tests (DVSA MOT data for tests in 2024, retests included). That's 7 points above the average of 82% across all models in the same data.

How much does a 2018 SEAT Mii cost to run?

Our estimate is £1,780 a year (£148 a month): £1,175 fuel, £200 road tax, £55 MOT and £350 predicted repairs, based on 7,400 miles a year. Insurance is not included.

What is the MOT pass rate for a 2018 SEAT Mii?

89% of 1,975 MOT tests on the 2018 SEAT Mii ended in a pass (DVSA MOT data for tests in 2024, retests included). That ranks it 379th of 607 models first registered in 2018 (bottom half).

Which year SEAT Mii has the best MOT pass rate?

Of the years with at least 100 tests, the 2019 SEAT Mii has the highest MOT pass rate at 93% and the 2012 the lowest at 81%. Newer cars usually pass more often simply because they are younger and have done fewer miles.

What is the average mileage for a 2018 SEAT Mii?

The average mileage recorded at MOT tests on the 2018 SEAT Mii is 33,651 miles, which is below the expected 44,400 miles for a 6-year-old car. This suggests lighter use than average, which generally means less wear on major components.