🚘 Japan Light-Vehicle Tax Calculator

Light-vehicle tax (軽自動車税, kei-jidōshazei) is the annual municipal tax on kei cars — Japan’s uniquely small cars up to 660cc engine, 3.4m long, 1.48m wide and 3.5m tall. Because of their compact size and low running costs, keis are hugely popular: roughly 4 in 10 new cars sold in Japan are kei vehicles. The tax is billed by your city or ward (not the prefecture), in the same May cycle as ordinary automobile tax.

A private kei car first registered on or after 1 April 2015 pays a flat 10,800 yen a year (7,200 yen for earlier registrations), whatever the engine size within the kei class. Kei vans and trucks pay 5,000 yen private or 3,800 yen business, and kei two-wheelers 3,600 yen. EV and CNG keis first registered between April 2025 and March 2026 get 75% off the first year’s bill. For ordinary cars see the automobile tax calculator.

The calculator takes the vehicle class, the first-registration period (rates rose in April 2015), the vehicle age, and whether it is a qualifying EV/CNG model first registered in the April 2025 – March 2026 window. Petrol and diesel keis pay an aged-vehicle surcharge of roughly 20% once 13 years have passed since first registration; electric, hybrid, gas and similar vehicles are exempt.

Green treatment.

Because the rate is flat, the only way a kei gets expensive is the aged-vehicle surcharge: a private kei over 13 years pays 12,900 yen instead of 10,800, and pre-April-2015 registrations — which kept the old 7,200-yen rate — jump straight to 12,900 once their 13 years run out. Compare the full-year cost of a kei against an ordinary compact with the automobile tax calculator — the difference is often more than 20,000 yen a year, which is a big part of the kei’s appeal.

1. Choose the vehicle class: private kei car, kei van/truck, kei business passenger, or two-wheeler.
2. Select the first-registration period (before or from April 2015) — older registrations pay the lower pre-2015 rates until the 13-year surcharge begins.
3. Mark whether it is a qualifying EV/CNG model first registered April 2025 - March 2026 (75% off year one).
4. Enter the vehicle age for the aged-vehicle surcharge check.
5. Click Calculate to see the annual tax and any reduction applied.

Why is kei tax a flat amount rather than by engine size?

Kei engines are all capped at 660cc, so displacement can’t discriminate. Instead the flat rate keeps running costs predictable and the class itself is the whole point — cheap, small, efficient city cars.

Is the light-vehicle tax different from automobile tax?

Yes — 軽自動車税 is billed by the municipality (city/ward) while 自動車税 is a prefectural tax on ordinary cars. The payment cycles are the same (May), but the rates and revenue destinations differ.

What is the eco reduction for keis?

Qualifying EV and CNG keis first registered between 1 April 2025 and 31 March 2026 pay just 25% of the rate in the first fiscal year — 2,700 yen for a private kei. From year two the full rate applies, and ordinary petrol keis currently get no fuel-economy discount.

Do kei trucks pay less?

Yes — kei vans and trucks pay 5,000 yen registered private (3,800 yen for business use) versus 10,800 for a private kei car. The registration class decides the rate.

Is the rate going up?

The statutory rates are unchanged: 10,800 yen for a private kei first registered from April 2015. Municipalities may raise the rate by ordinance up to 1.5 times, but hardly any do for keis, and no increase is scheduled — check your city’s notice for the binding figure.

What happens to my kei tax if I move cities?

The tax is paid to the municipality where the vehicle is registered, not where you live. The standard rates are the same nationwide, so moving does not change the amount.

This tool is for informational purposes only and does not constitute financial advice. Consult a qualified financial professional for advice specific to your situation.

Kei vans and trucks pay 5,000 yen private or 3,800 yen business versus 10,800 for a private kei car — but insurance also reads the registration class, so don’t register a personal car as commercial just to save tax. If you buy a used kei mid-year the tax is pro-rated from the month of registration. Keis first registered before April 2015 keep the old lower rates until 13 years have passed, then pay the aged-vehicle rate (12,900 yen private); electric and hybrid keis are exempt from that surcharge. EV/CNG keis first registered between April 2025 and March 2026 get 75% off the first year’s bill. Add fuel and insurance with the fuel cost calculator to get the true monthly cost.