Japanese Car Insurance Grade Premium Calculator
Enter your current voluntary car insurance premium and Japanese no-fleet grade to estimate the annual premium at another grade or accident coefficient. Includes a static grade 1-20 discount and surcharge table.
Japanese car insurance grade discount and surcharge table
Japanese no-fleet policies use grades 1 through 20. From grade 7, separate no-accident and accident coefficients apply. Negative figures are discounts and positive figures are surcharges.
| Grade | No accident | Accident |
|---|---|---|
| 1 grade | +108% | Not separate |
| 2 grade | +63% | Not separate |
| 3 grade | +38% | Not separate |
| 4 grade | +7% | Not separate |
| 5 grade | -2% | Not separate |
| 6 grade | -13% | Not separate |
| 7 grade | -27% | -14% |
| 8 grade | -38% | -15% |
| 9 grade | -44% | -18% |
| 10 grade | -46% | -19% |
| 11 grade | -48% | -20% |
| 12 grade | -50% | -22% |
| 13 grade | -51% | -24% |
| 14 grade | -52% | -25% |
| 15 grade | -53% | -28% |
| 16 grade | -54% | -32% |
| 17 grade | -55% | -44% |
| 18 grade | -56% | -46% |
| 19 grade | -57% | -50% |
| 20 grade | -63% | -51% |
Rates use the revised reference pure premium coefficients published by the General Insurance Rating Organization of Japan in June 2021. Actual application can vary by insurer and policy start date.
What Japan’s no-fleet grade system is
Voluntary motor insurance in Japan runs on a **no-fleet grade system**, under which every policyholder is assigned a grade from 1 to 20. The higher the grade the lower the premium; making a claim drops the grade and raises the premium. A new policy starts at grade 6 and rises by one each year without a claim. Where a claim is made, the grade falls by three or by one according to the kind of accident.
From grade 7 upward there are moreover two coefficients — **the no-accident and the accident coefficient** — and at the same grade the accident coefficient gives the smaller discount. After a claim the accident coefficient applies for a set number of years, and the premium does not return until that spell has run its course. Enter your present annual premium, grade and coefficient and this tool shows the premium you would face at another grade or coefficient, with the difference. It is an estimate on the assumption that **everything besides the grade — vehicle, cover and the rest — stays the same**.
How to use the grade premium simulator
- Enter your present annual premium Give the yearly figure from your policy document or renewal notice. It is the baseline of the comparison.
- Choose your present grade and coefficient Pick the grade from 1 to 20 and whether the no-accident or the accident coefficient applies. From grade 7 upward the coefficient changes the discount.
- Choose the grade and coefficient to compare Enter the grade you would fall to after a claim, or rise to after a clean year. If you are picturing a claim, switch the coefficient to the accident one as well.
- Read the difference You get the estimated annual premium at that grade together with the change in rate and in yen — something to weigh when deciding whether to claim at all.
- Take in the whole table The discounts and surcharges for grades 1 to 20 are set out together. A minus is a discount, a plus a surcharge.
Tips for getting more out of it
- Check your policy certificate or insurer account for the annual premium, current grade, and remaining accident-coefficient period before entering the values.
- To explore whether making a claim could cost more later, lower the current grade by three and select the accident coefficient as a common scenario. Some accidents lower the grade by one or do not count, so confirm the treatment with your insurer.
- A first policy normally starts at grade 6. A qualifying second-car policy may start at grade 7, and a claim-free year generally raises the policy by one grade.
- This comparison isolates only the grade effect. Your renewal premium can still change when the vehicle rating class, age band, coverage, or insurer base rates change.
Where the simulator helps
When you are unsure whether to claim
Claiming for a small loss raises the premium for several years to come. Seeing the increase at the lower grade tells you whether paying for the repair yourself works out cheaper.
Projecting next year’s premium
You learn what the figure becomes after a clean year takes you up a grade — something to fold into the household’s plans.
Allowing for the years under the accident coefficient
A claim not only drops the grade but leaves the accident coefficient in force for years. Here you can see in figures that the same grade costs differently under each coefficient.
Measuring what a high grade is worth
The discount at grade 20 is far from that at grade 10. It shows what years of driving without a claim amount to in money.
When you want to examine a claim more closely
To set repair costs against the rise in premium, see the claim break-even calculator; for the discount on a second car, the second-car discount check; for the compulsory cover, compulsory insurance premiums.
Terms about motor insurance grades
- No-fleet grade
- The grade system applied to policyholders owning or using nine vehicles or fewer. Grades run from 1 to 20, and the higher the grade the larger the discount.
- No-accident coefficient
- The coefficient applied to a policy under which no claim has been made. From grade 7 upward it gives a larger discount than the accident coefficient at the same grade.
- Accident coefficient
- The coefficient applied for a set number of years to a policy under which a claim has been made. At the same grade the discount is smaller and the premium higher.
- Three-grade accident
- The category covering most claims, such as damage to property or to the vehicle. The grade falls by three the following year, and the accident coefficient stays in force for three years.
- One-grade accident
- The category for a limited set of losses, such as theft or damage from a falling object. The grade falls by one and the accident coefficient applies for a single year.
- No-count accident
- The category of claims that leave the following year’s grade untouched, such as a payment under personal injury cover alone. Claiming does not lower the grade.
- Model-based rating class
- The premium band settled for each vehicle model from its claims record. It bears on the premium separately from the grade, so changing car changes the premium even at the same grade.
Frequently asked questions
Side Note — The grade system looks mainly at claim count, not claim size
Japan's no-fleet grade system primarily reflects whether claims occurred and how many there were. In principle, a three-grade-down claim changes the next grade in the same way whether the insurer paid a modest repair bill or a very large loss. For a small claim, policyholders sometimes compare the payout with the extra premiums expected over the following years before deciding whether to claim.
The accident-coefficient period affects price separately from the grade reduction. A claim-free policy that reached grade 10 and a policy that fell from grade 13 to grade 10 can have the same grade number but different discounts. This calculator exposes grade and coefficient as separate choices so that both effects remain visible.
Actual premiums also reflect the loss experience of each vehicle model. Japanese regular and compact passenger cars have rating classes 1-17 for each coverage type, while kei passenger cars use classes 1-7, reviewed annually. Your renewal can therefore move even when you personally had no accident, which is why comparable quotes remain important.