What are guaranteed additions? 

Guaranteed additions are additional benefits that you will get at the time of policy maturity. The insurance provider will calculate the guaranteed addition payout amount for you based on the policy term, premium payment term, the age at the time of policy purchase, and the annual premium amount.

Please check the below table for more details on this:

Guaranteed Additions        
Age as on last birthday 7(PPT)/10 (PT) 7(PPT)/15(PT) 8(PPT)/15(PT) 10(PPT)/15(PT) 5(PPT)/20(PT) 7(PPT)/20(PT) 8(PPT)/20(PT)
18 to 24 years 0.01 4.00 5.50 8.84 4.22 8.85 11.23
25 to 34 years 0.01 3.54 4.99 8.11 3.50 8.04 10.34
35 to 45 years         0.01   3.30  4.72 7.59 3.37 7.64 9.96
46 to 55 years    0.01 2.78 4.14   7.33 NA NA NA

Let’s take an example: 

Policyholder age 40 years
Sum assured ₹5,00,000
Policy term 15 years
Premium payment term 10 years
Guaranteed additions 7.59*₹50,000 = ₹3,79,500 (Guaranteed addition factor * annual premium)
Guaranteed addition payout amount (on maturity) ₹5,00,000 + ₹3,79,500 = ₹8,79,500