How do you estimate the value of your audience when selling sponsorships?

I've been thinking a lot about audience monetization lately, especially for founders and indie makers.

Many of us slowly build small but valuable audiences over time:

• newsletters about startups or AI

• niche blogs or dev communities

• SaaS products with engaged users

• waitlists or early adopter communities

• founder-focused X / Twitter audiences

At some point sponsorships start to make sense.

But there's a practical problem I rarely see discussed:

How do you actually price your audience?

For example:

• a dev newsletter with ~3k subscribers

• a SaaS product with 5k–10k active users

• a niche founder community

• a blog with ~20k monthly readers

How do you translate that into a sponsorship price?

Do you charge CPM?

Flat sponsorship packages?

Performance deals?

From what I've seen, many founders end up guessing, either underpricing massively or avoiding sponsorships because they're unsure what a fair price looks like.

I built a simple calculator that tries to estimate potential sponsorship pricing based on traffic and engagement: https://adsly.io/calculator

It's obviously just a rough estimate, but the goal is to give founders and creators a starting point instead of guessing.

Curious how others here approach this.

How do you price sponsorships for your audience?