how much the credit score can get down due to one late payment?

Your recent late payment might cause you as much as a 90 points to 110 points drop on your FICO score, if you have an excellent score of 780 or higher.

Your credit score will be affected as soon as any late payments shows up on your credit report. You might know that one of the important constituents of credit score is payment history, which accounts 35% of it. So, being late on your payments can drop your credit score by a substantial amount. So, if you can't pay off your outstanding balance amount in full, try to pay off the minimum balance amount for your credit cards.

I think 100 points will be deducted for this.

See, it depends on many factors. For instance, if you're late on your payment by only one day, then the lender may not even report it on your credit report. Most lenders report late payments when you're 30-plus days past due. If your payment is due on Feb 10 and you make the payment on Feb 25, then you may have to pay late fees but this late payment will not be reported on your credit report. In that case, your credit score won't go down.