For the Standard cards, the billing cycle is 30 calendar days and the grace period is 5 calendar days.
Let's say that your statement day of your standard card is 1st of every month, and you spent Rs. 100 on January, 10,2021. In that case, your statement with that Rs. 100 card spend would be generated and shared with you on 1st February, 2021, and your due date for the payment would be February, 5,2021.
For the Booster cards, the billing cycle is 1 working day only.
Let's say that you spent Rs. 100 on January, 1, 2021, and January, 1st is Monday. In that case, we would generate statement with Rs. 100 card spend on January 2, 2021 and share with you over email early morning. On January, 2,2021 itself, the outstanding amount would be automatically deducted via NACH and the card would be topped up with that amount.
You can check your card Standard card due date on Karbon Dashboard.
Cards => Due Date text in Standard card section