Podcast ad revenue is one of the few creator income streams still priced the old-fashioned way: cost per thousand downloads, same as radio and TV before it. That makes it more predictable than a platform algorithm's RPM, but only if you plug in numbers you actually control — your real download count, a CPM your show can command, and how many ad spots you're actually selling. This calculator turns those four inputs into a per-episode and monthly estimate you can use in a media kit or a sponsor pitch.
How it works
The math is a straight multiplication chain, not a lookup table. It divides your downloads per episode by 1,000 to get the number of "CPM units," multiplies that by your CPM rate to get what one ad slot is worth, then multiplies again by how many ad slots you run per episode — since a show selling both a pre-roll and a mid-roll effectively doubles its per-episode ad revenue at the same download count. That per-episode figure is rounded to the cent, then multiplied by your episodes per month to get the monthly total, so the monthly number is always exactly the displayed per-episode figure times your publishing cadence — no hidden rounding drift between the two.
CPM itself isn't fixed — it swings by where the ad sits in the episode. Pre-roll ads typically run $18-25 per 1,000 downloads, mid-roll host-read ads (the ones your audience trusts most) run higher at roughly $25-30+, and post-roll ads — heard only by listeners who finish the episode — usually price lowest of the three.
Worked example
Take a show averaging 10,000 downloads per episode, selling 2 ad slots at a $25 CPM, and publishing 4 episodes a month.
- CPM units: 10,000 ÷ 1,000 = 10
- Per-episode revenue: 10 × $25 × 2 slots = $500
- Monthly revenue: $500 × 4 episodes = $2,000
That show is earning roughly $2,000 a month from ads alone. Sell a third slot at the same rate and the same math pushes per-episode revenue to $750 and monthly revenue to $3,000 — the model scales linearly with every input, which is exactly what makes it useful for testing "what if I raised my rate" or "what if I added an episode a week" before you pitch a sponsor.
How to interpret your result
Treat this as the revenue a fully-sold slate of episodes would generate at your stated CPM — not as a forecast of what a network will actually pay you. Two things this calculator can't see will move your real number: fill rate (ad networks rarely sell 100% of your inventory every month, so unsold slots earn nothing) and download timing (your CPM is usually priced against a 7-day or 30-day guarantee, and using the wrong window will make your estimate too rosy). If you're quoting a sponsor directly rather than going through a network, your fill rate is effectively whatever you can close yourself.
This also only estimates CPM-based ad revenue — the download-times-rate math that applies to pre-roll, mid-roll, and post-roll spots sold at a stated rate. Affiliate and promo-code commissions, listener-supported subscriptions (Patreon, Apple Podcasts Subscriptions), and one-off sponsorship bonuses negotiated outside the CPM model are real income for many shows but aren't counted here — add them on top of whatever this tool reports.
Methodology & sources
The formulas are perEpisodeRevenue = round2((downloadsPerEpisode / 1,000) × CPM × adSlotsPerEpisode) and monthlyRevenue = round2(perEpisodeRevenue × episodesPerMonth) — the monthly figure is built from the already-rounded per-episode number, so it always matches what you'd get multiplying the two displayed figures yourself.
The CPM bands used in the help text and above — roughly $18-25 for pre-roll, $25-30+ for mid-roll host-read, and $15-20 for post-roll — reflect current industry benchmarks reported in Castos' podcast advertising guide, which also notes that host-read ads convert 2-3x better than pre-produced ones and typically command the highest rates on a show. These are market ranges compiled from publicly reported rate cards and network averages, not a rate any specific advertiser owes you — your show's actual CPM depends on your genre, audience demographics, and whether you're negotiating directly or selling through a network that takes a cut before you ever see a payout.