JP Pension Forecast Explanation

[Seasider4374]

Can someone explain the figures I'm seeing online for my JP pension?

Having checked yesterday I can see 86 kokumin nenkin, and 39 kosei nenkin months paid. Assuming my freelance status remains I'll have 96 more kokumin nenkin payments to age 60 to make for a total of 86+39+96 = 221 months. I.e. my pro-rata payment would be 221/480months = 0.46 of the full pension, and so I was expecting to see a forecast of 816,000 x 0.46 = 375,700 .

But I am shown my pension forecast as being 432,120 yen/yr basic pension plus 50,689 yen/yr for the Kosei portion (if drawn at age 65).

How has the 432k figure been reached? Is it the 375k figure but allowing for inflationary rises until such time I draw my pension?

Also why is my kosei portion so small relative to my kokumin portion (the ratio between the total months', 182 vs 39, does not tally with the payments those months will provide me 432k vs 50k. When I paid those kosei amounts my payments alone (21k monthly) were more than a monthly kokumin amount would have been, not even considering the employers' payments...)

(I know it's all small change anyway in the grand scheme of my later life finances but I like to know how figures are reached...)

[RetireJapan]

It depends how old you are. Up to a certain age, the nenkin teikibin shows 'pension based on payments to date'. After that age, it shows 'pension based on payments to age 65'.

I believe the age is 55, but I'm not 100% sure. Your statement will clearly state which it is.

One reason your kosei nenkin projection is small is that the kokumin nenkin portion of your kosei payments is included in the kokumin nenkin projection (kosei nenkin includes kokumin nenkin as well).

[TunaSki]

Also why is my kosei portion so small relative to my kokumin portion (the ratio between the total months', 182 vs 39, does not tally with the payments those months will provide me 432k vs 50k. When I paid those kosei amounts my payments alone (21k monthly) were more than a monthly kokumin amount would have been, not even considering the employers' payments...)

Your Kosei portion is small because only 39 months of contributions into Kosei.

The Kosei contributions do also include Kokumin contributions too though. So you actually have 182 Kokumin (as class 1) + 39 Kokumin (as class 2) + 39 Kosei (as class 2)

Also to make you feel better about your Kosei contributions costing you ¥21,000 per month for those 39 months, then because they also include Kokumin contributions (let’s say ¥16,500 per month), it means for those 39 Kosei months you get an extra ¥50,000 per year for life (from age 65), for only an additional ¥4,500 per month for 39 months! (With the added bonus that you also got an extra tax deduction 39x ¥4,500 while paying that extra ¥4,500 contribution took