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Podcast Cross-Promo Listener Estimator

Estimates how many new listeners a promo on another podcast is likely to send you, how many stick around after a month, and what that reach would cost as a paid host-read ad.

Your numbers

Results update as you type.

Your estimate

Listeners who hear your promo...
New listeners who try your show...
Listeners retained after 30 days...
Equivalent paid ad cost...

Estimates only. Assumptions are listed below, and you can change every input.

A promo swap with another podcast sounds like free growth, but most hosts have no idea what to expect from it. They trade a mid-roll on a show with 3,000 downloads per episode, see a small bump in their own numbers, and cannot tell whether that was a good deal or a waste of two minutes of airtime. Without a rough expectation up front, it is impossible to know which partners are worth doing again.

This estimator starts from your partner's downloads per episode and the number of episodes carrying your promo, applies a listen-through rate for the placement you picked, then uses your own conversion and retention rates to estimate how many people try your show and how many are still listening a month later. It also prices the same reach as a paid ad using a CPM you set, so you can see the value of the airtime you are trading. Every rate is either an input you control or an assumption listed below, and none of it comes from data about your specific show.

How to use this tool

  1. Ask your partner for their 30-day downloads on a typical recent episode and how many episodes will carry your promo.
  2. Pick the placement you have been offered, then enter a conservative conversion rate and the retention rate you see on your own new listeners.
  3. Enter the CPM you would pay for a host-read ad on a similar show and compare the paid equivalent with what your own airtime is worth to them.

What the math assumes

  • Listen-through to the promo is assumed at 90% for pre-roll, 75% for mid-roll and 40% for post-roll. These are the only constants baked into the math and they are rough working figures, not measured data.
  • Every download is treated as one listener who hears the episode; re-downloads, shared devices and skipped promos are ignored.
  • Conversion and retention use exactly the rates you enter. The tool has no data on your show and does not predict them.
  • Equivalent paid ad cost = total downloads across the promo episodes divided by 1,000, times your CPM, which mirrors how host-read podcast ads are usually priced.
  • Each episode is assumed to reach a mostly fresh audience. Heavy overlap between the partner's episodes would lower the real numbers.

Frequently asked questions

Why does placement change the result so much?

Because not everyone finishes an episode. A pre-roll is heard by nearly everyone who presses play, while a post-roll only reaches people who stay to the end, so the same download count delivers very different exposure.

What conversion rate should I use if I have never done a swap?

Start low, around 1% to 2% of people who hear the promo, and treat it as a placeholder. After your first swap, replace it with the actual number of new followers you saw in the week after the episode went out.

Is the paid equivalent what my promo is worth?

It is what the same reach would roughly cost as a host-read ad at the CPM you entered. It is a useful anchor for negotiating a fair trade, not a valuation of your show or of the listeners you gain.

Should I use downloads or unique listeners?

Use 30-day downloads per episode, since that is the figure most hosts have and the one ads are priced on. If your partner shares unique listeners instead, expect the real numbers to be a bit lower than this estimate.

Link to this toolhttps://crosspromoly.com/tools/podcast-swap-listener-estimate/

Free for readers and publishers alike. If you cite the result in an article, a link to this page helps others find it.

More free tools from CrossPromoly

  • Newsletter Swap Fairness Calculator: Estimates how many clicks each newsletter actually delivers in a swap so you and your partner can agree on a fair number of placements before anyone writes copy.
  • Audience Swap Time ROI Calculator: Works out what your cross-promotion swaps really cost in hours and tools, what each new subscriber costs you, and how that compares with buying the same growth through paid ads.

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