Can we add up current year bonus (eg. 1 month) and base pay then multiple to a % (eg. 20%) as the expected salary figure for the HR?

Hi Anon. I'm a HR so i can give you some view points.

We usually look at 2 factors: Annual Base Salary (ABS) and Total Target Cash (TTC) to determine budget for salary. ABS means your total monthly fix pay x12 + AWS. TTC is ABS + bonus. From budget standpoint, we would look at your annual amount to determine how much to pay you.

If your potential company pays variable bonus, you can consider using annual figure to negotiate. If doesn't pay bonus, you can use annual figure and work backwards to determine your expected monthly salary.

Advice is to match apple to apple. You wouldn't want a case where your new company pays high monthly basic but low in bonus. Your total package might end up worse off than your previous company.​​​

You can add a multiple but not the bonus. Base salary excludes any AWS, bonus, etc. If you add them all up, it becomes total compensation.