I have an audience size
I have a monthly budget
Total LinkedIn Audience
Enter your total audience size as in your LinkedIn campaign manager.
CPM
Pull up last month's data for this audience and find the Cost Per Impression (CPM). A CPM on LinkedIn currently hovers around 30$ within the business/tech industry.
Audience Penetration
I recommend you keep this between 70-80% = 0.7-0.8 for meaningful awareness per month. The higher the number the higher the ability to convert the 5% of buyers who are in-market right now and reach the 95% of buyers who aren't.
Velocity
How long it takes to achieve total audience penetration? Velocity affects the reach per month. Recommendation: TOFU = 3 months. MOFU = 2 months. BOFU = 1 month.
Frequency
How often a individual sees your ads per month. A frequency between 8-10 per month is a good starting point, depending on how known your brand is to the audience.