How Much Money Can a Website Make From Ads? The Real Math Behind Ad Revenue
It's the question every new publisher asks, and the honest answer is "it depends." But it depends on a small number of things you can actually measure, and once you see how they multiply together, ad revenue stops feeling mysterious. This guide gives you the formula, walks through worked examples, and shows which lever moves the number most.
All figures below are illustrative examples chosen to make the math easy to follow, not benchmarks or promises. Your real numbers will depend on your traffic, content, geography, and setup.
The Core Formula
Website ad revenue comes down to four inputs:
Revenue = Pageviews × Ad Units Per Page × Fill Rate × (eCPM ÷ 1,000)
- Pageviews is how many pages visitors load.
- Ad units per page is how many ad slots each page offers.
- Fill rate is the share of those slots that actually return an ad.
- eCPM is your effective revenue per thousand filled impressions.
Each input multiplies the others, which is why improving more than one at a time compounds.
Worked Example: A Site With 100,000 Pageviews
Assume a site with 100,000 monthly pageviews, 3 ad units per page, a 60% fill rate, and an eCPM of 2 dollars.
- Ad requests: 100,000 × 3 = 300,000
- Filled impressions: 300,000 × 60% = 180,000
- Revenue: 180,000 × (2 ÷ 1,000) = 360 dollars
That works out to a page RPM of 3.60 dollars, meaning about 3.60 dollars earned per thousand pageviews.
What Happens When You Improve One Lever
Improve fill rate from 60% to 85%. Filled impressions rise to 255,000, so revenue becomes 255,000 × (2 ÷ 1,000) = 510 dollars. That's about 42% more revenue from the same traffic, with no change in pricing.
Improve eCPM from 2 to 2.50 dollars at the original 60% fill. Revenue becomes 180,000 × (2.50 ÷ 1,000) = 450 dollars, a 25% increase.
Improve both. At 85% fill and 2.50 dollars eCPM, revenue becomes 255,000 × (2.50 ÷ 1,000) = 637.50 dollars, about 77% above the starting point.
The takeaway: you don't always need more visitors. Improving how well existing traffic is monetized can move revenue substantially.
What Happens When Traffic Grows
Now take the same setup and multiply traffic by ten, to 1,000,000 pageviews, with the original 60% fill and 2 dollar eCPM. Revenue scales to 3,600 dollars. Improve fill to 85% and it becomes 5,100 dollars. The monetization improvement is worth the same percentage at any scale, but the absolute gain grows with traffic.
Why Real Results Vary So Much
Geography. The same pageviews earn very different eCPMs depending on where visitors are, because advertiser budgets are concentrated in certain markets.
Content category. Commercial intent topics tend to attract higher bids than general interest content.
Device and format. Mobile, desktop, display, native, and video all price differently.
Seasonality. Demand typically peaks in the fourth quarter and cools in January.
Placement and viewability. Ads that are actually seen tend to earn more than ads buried far down a page.
Traffic quality. Clean, verifiable traffic attracts stronger bidding.
Fill Rate: The Lever People Forget
Most beginners focus on eCPM, since it's the number networks advertise. But unfilled impressions earn nothing at all. If a third or more of your slots go unfilled, that's revenue you never see on any report, because the missing impressions simply don't appear. Checking fill rate, and in particular fill rate on remnant inventory, is often the fastest way to find money that was always available.
A Quick Way to Estimate Your Own Numbers
- Find your monthly pageviews in your analytics.
- Count the ad units on a typical page.
- Find your fill rate and eCPM in your ad platform reports.
- Plug them into the formula and compare the result to your actual earnings.
If the formula result and your real revenue are far apart, one of the inputs, often fill rate, is telling you something worth investigating.
Where Remnant Inventory Fits In
Remnant inventory is the part of your slots that primary demand didn't fill. On a typical setup it can be a large share of total impressions, and it's often the part running at the lowest fill rate. That makes it the easiest place to improve the fill rate input in the formula above. Moving unfilled impressions from a static fallback to real time, per impression evaluation is one practical way to push that input up without touching your content or your traffic.
Frequently Asked Questions
How much can I earn per 1,000 pageviews?
It varies enormously. The formula above shows how: with 3 ad units, 60% fill, and a 2 dollar eCPM, you'd earn 3.60 dollars per 1,000 pageviews. Different inputs give very different results, so measure your own.
What's the difference between RPM and eCPM?
eCPM is revenue per thousand ad impressions. RPM is revenue per thousand pageviews, so it also reflects how many ads each page carries and how often they fill.
Is it better to add more ad units or improve fill rate?
Improving fill rate on the slots you already have is usually safer, since adding more units can hurt user experience and viewability.
Why is my revenue lower than the formula predicts?
Check fill rate first, then viewability and any price floors that might be blocking bids.
Key Takeaways
- Ad revenue equals pageviews times ad units per page times fill rate times eCPM divided by 1,000.
- Each input multiplies the others, so improving fill rate and eCPM together compounds.
- In the worked example, lifting fill rate from 60% to 85% alone added about 42% more revenue from identical traffic.
- Remnant inventory is often where fill rate is weakest, making it a practical place to find extra revenue.