Kernel Save interest will be calculated on your daily available balance and paid monthly, at the start of the month following, generally within a couple of days. The Kernel Save interest rate is subject to change based on the Official Cash Rate (OCR).
The current interest rate for Kernel Save is shown on the product's Overview page in the Kernel platform, or on Kernel's website here:
Historic OCR changes can be found on the RBNZ's website: https://www.rbnz.govt.nz/monetary-policy/monetary-policy-decisions