What conversion rate do you need before leaving Substack saves money?

Two bills that move on different axes

Substack charges 10% of paid-subscription revenue and nothing for hosting your list, so its bill is indifferent to how many readers you have and entirely a function of how much they pay you. Ghost, beehiiv and Buttondown do the opposite: a plan fee that scales with your list, and 0% of the subscription revenue. Kit sits closest to them, charging a plan fee plus a 3.5% + $0.30 commerce fee that is far smaller than Substack's cut. Either way their bills are driven by how many readers you have rather than what those readers pay you. Those are not two prices on the same scale. They are two different quantities, and which one is smaller depends on the ratio between them.

That ratio has a name creators already use: the share of your list that pays. Ask "at what revenue does a flat fee win" and the answer changes every time your list does; ask "what share of my readers has to pay" and you get a number you can check against your own dashboard. This article computes that bar. Every figure comes from published pricing verified as of 2026-09-08, at $10/month per paid subscriber, using annual plan billing wherever it is cheaper — and each list size below is one of Ghost's own bracket boundaries rather than a round number picked to make a point.

The single-crossover version of this question — hold one list size, grow the revenue — is in flat fee or revenue share. What that framing cannot show is the thing this one is about: the bar is not a constant.

The bar gets lower as your list gets bigger

On Ghost, a 1,000-member list needs 28 paying members before Ghost costs less than Substack — 2.80% of the list. At 100,000 members it needs 257, which is 0.26%. The bar falls at every rung in between: 1.72% at 2,500, 1.18% at 5,000, 0.99% at 7,500, 0.83% at 10,000, 0.53% at 25,000, 0.39% at 50,000, 0.30% at 75,000. Grow the list 100× and the number of paying readers you need grows only 9.2×, so the rate you have to hit drops by about 10.9×.

The reason is in the shape of the plan fee. Ghost's price climbs as your list does, but far more slowly than the list itself — that is what a bracketed ladder does, and it is mapped in the subscriber counts where your newsletter bill jumps. Substack's cut, by contrast, is a straight percentage with no ceiling: it grows exactly as fast as your revenue. A big list is therefore structurally friendlier to a flat fee than a small one, and the creators for whom Substack's 10% is genuinely the cheaper deal are mostly the ones who have not grown yet.

Kit behaves the same way once you are paying it: from 25,000 subscribers, where its bar is 0.66%, down to 0.55% at 75,000. Below that it is a special case worth knowing: Kit's free Newsletter plan supports paid subscriptions to 10,000 subscribers, so under that ceiling the bar is 1 paid subscriber — Kit is cheaper than Substack from the first reader who pays you. Kit publishes bracket prices to 95,000 subscribers, so it has no quotable bar at 100,000; above its ladder it is contact-sales. The two ladders side by side are in Ghost vs Kit.

Below the bar, Substack really is the cheaper platform

This is the part worth being blunt about, because the rest of this site spends most of its time on the sizes where flat fees win. At 10,000 members with 41 paying — 0.41%, comfortably under the 0.83% bar — Substack costs $68.06/month and Ghost costs $112.19. Switching at that point does not save money; it costs $529.56 a year. A plan fee is charged whether or not anyone is paying you, and a percentage of very little is very little.

Cross the bar and it reverses just as cleanly. Same list, 166 paying (1.66%): Substack $275.56/month against Ghost's $185.94 — $1,075.44 a year the other way. Nothing about either platform changed. The only thing that moved is the ratio, which is why "which platform is cheapest" has no answer that survives being quoted without a list size and a conversion rate attached to it.

Your subscription price moves the bar as well, and in the direction you would expect: at 10,000 members, charging $5/month instead of $10 raises Ghost's bar to 1.65%, and charging $20 lowers it to 0.42%. Fewer, better-paying subscribers clear the bar sooner than many cheap ones — the mechanics of why are in does your subscription price change what you pay in fees, and the related question of when charging covers the bill at all is in how many paid subscribers it takes to cover your platform bill.

Every platform has its own bar

At 2,000 subscribers — small enough that all four alternatives can be quoted from verified data — the bars are Kit 0.05%, Buttondown 1.40%, beehiiv 2.05%, Ghost 2.15%. They line up with plan fee exactly: Kit has both the cheapest plan at this size ($0/month) and the lowest bar, Ghost the dearest ($46) and the highest. Since Ghost, beehiiv and Buttondown all take 0% of subscription revenue, and Kit's 3.5% + $0.30 is small next to Substack's 10%, what you are really comparing at this size is one plan fee against Substack's cut of a small revenue.

Two honest limits on those numbers. beehiiv's plan prices were read at its pricing page's default list size, and beehiiv has historically scaled price with subscriber count, so its bar is quoted here only inside the 2,500-subscriber range we have actually verified — do not extend it up the ladder. Buttondown publishes brackets to 20,000 subscribers and is contact-sales above that, and its annual-billing discount is not something we have been able to confirm, so its figures assume monthly billing. Both caveats are on the methodology page.

The practical version is short. Find your own rate — paying subscribers divided by total list — and compare it against the bar for the list size you are at now, not the one you hope for. If you are under it, a revenue share is doing you a favor and the flat-fee comparison is a trap; if you are over it, the gap compounds every month you wait. Your own numbers go in the calculator, and how much Substack actually costs breaks down the 16.6% you are really paying it once Stripe is included.

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