Switching from Kit to Substack: what happens to your fees

What actually changes when you switch

Every other move in this series either leaves a revenue share behind or trades one flat fee for another. This one runs toward the revenue share, and people make it for a reason the fee math cannot see — Substack's recommendations, app and Notes bring readers in a way Kit does not try to. So the honest framing is not "which is cheaper" but "what does the network cost". Start with the mechanics. Kit charges nothing for the list up to 10,000 subscribers and a plan fee that steps up with list size above that, plus Kit Commerce's 3.5% + $0.30 on each paid subscription with payment processing already included. Substack charges no plan fee at any size, but takes 10% of every subscription, and you pay Stripe's 2.9% + $0.30 card fee and its 0.7% recurring-billing fee on top — 13.6% of the subscription before the per-transaction cents.

On a $10/month subscription that is $1.66 per paid subscriber per month on Substack against $0.65 on Kit — 2.6× as much. Above Kit's free tier the trade is a fixed bill you stop paying for a percentage you start paying, and which side wins depends on how many people pay you; inside the free tier there is no fixed bill to stop paying, and the percentage is all that changes. Both platforms are verified here to 100,000 subscribers (as of 2026-09-08), so the scenarios below can sit anywhere on the ladder. The three-scenario side-by-side is on Kit vs Substack; the fee structures on their own are in Kit pricing explained and how much Substack actually costs.

For most paid lists, the move raises your bill

Take a list just past Kit's free tier: 15,000 subscribers with 600 paying $10/month — $6,000/month gross. On Kit's Creator plan that costs $530.83/month all-in (8.85% of gross): $140.83 of plan fee and $390 of commerce fee. On Substack the same newsletter costs $996/month (16.6%), all of it fees on revenue. The move costs $465.17/month more — about $5,582 a year — for identical income, even after the plan fee disappears. That is the price of the network at this size.

It scales with revenue, because the thing you are now paying is a percentage. At 25,000 subscribers with 1,000 paid at $10/month ($10,000/month gross), Kit's Creator plan comes to $815.83/month (8.16% of gross) and Substack to $1,660 (16.6%) — a premium of $844.17/month, roughly $10,130 a year. Notice the two percentages: Kit's falls as the paid base grows because its plan fee is spread over more revenue, while Substack's stays pinned at 16.6% no matter how large you get. More revenue only widens that gap; the one thing that narrows it is a Kit plan fee spread over a thin paid base, which is the next section. The same move in the other direction is covered in switching from Substack to Kit.

The one range where Substack is cheaper

A flat fee is only a burden if you cannot spread it, so the move saves money exactly when your paid base is thin relative to your list — and only above Kit's free tier, where there is a plan fee to escape. On the 15,000-subscriber list above at $10/month, Substack is the cheaper home below 140 paid subscribers ($1,400/month gross, a 0.93% conversion rate). With 70 paid subscribers, for instance, Kit's Creator plan fee still has to be paid and the bill is $186.33/month, against $116.20 on Substack — a $70.13/month saving for moving. On the 25,000-subscriber list the bar is 165 paid subscribers ($1,650/month gross) — higher in absolute terms because Kit's bracket costs more, but a lower share of the list. What conversion rate you need before leaving Substack saves money walks that bar across every list size.

Inside Kit's free tier the answer is simpler, and it runs the other way. Kit's free plan covers up to 10,000 subscribers and can sell paid subscriptions with no plan fee at all, so there is nothing for Substack's $0 plan to undercut — at $10/month the cost model finds no paid count on a 10,000-subscriber list at which Substack is cheaper. A 5,000-subscriber list with 150 paying $10/month pays $97.50/month on Kit (6.5% of gross, all of it the commerce fee) and $249 on Substack (16.6%) — $151.50/month more for the move, with no plan fee saved to offset it. If you are near the line at any size, put your real paid count into the calculator before deciding — and the companion question, how many paid subscribers it takes to cover a platform bill, is the same arithmetic from Kit's side.

What the premium has to buy, and what to verify

The useful way to hold a $465.17/month premium is as a growth budget with a target attached. Each new paid subscriber on Substack nets you $8.34 after its fees at $10/month, so on the 15,000-subscriber list Substack's network has to bring in 56 extra paid subscribers — 9.33% more than you have — before the move is fee-neutral, 102 (10.2% more) on the 25,000-subscriber list, and 19 on the 5,000-subscriber list inside the free tier. Those are not outlandish numbers, and they are not guaranteed ones either; if you cannot name the mechanism that produces them, the premium is simply a cost. Everything above that target is what you are actually buying.

Before you move, confirm the things that cost real money. Paid subscribers on Kit are billed through Kit Commerce, and Substack bills through its own Stripe connection — different payment rails — so ask both platforms specifically whether existing subscriptions can carry over without readers re-entering cards, and how annual subscribers are handled mid-term. You will also be leaving Kit's automations, tagging and digital-product sales behind; Substack is built around the publication and the network, not a marketing stack, and that is a real trade even when the fee math is close. We keep migration mechanics out of the data layer because they change often. The fee profiles behind every figure here are on the Kit and Substack profile pages, with sources on the methodology page.

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