Method & limits

How the numbers are made

Formula

monthly platform cost = plan price + platform share % × R + card % × R + per-payment fee × S (omitted where the vendor's rate already includes cards) R = monthly gross sales = paying subscribers × price (or course revenue) S = number of payments that month You keep = R − monthly platform cost

Vendor facts vs processor assumptions. Plan prices, platform shares and transaction fees are vendor facts from each page. Card-processing rates are a second layer with five treatments, shown beside every result: vendor-stated (beehiiv says Stripe’s standard fee applies), vendor-published (Kajabi Payments 2.9%/2.8% + $0.30), included (Kit’s 3.5% + 30¢ includes card processing) and assumed (Substack, Ghost, Teachable, MailerLite, Patreon: the page does not state the rate, so the editable generic Stripe rate is used and the result is tagged) and not stated (Skool: the page gives a transaction fee but not whether processing is inside it; none is added and the result is tagged as possibly understating). Podia’s FAQ names the typical Stripe/PayPal rate, so it is treated as vendor-stated.
Annual vs monthly billing is shown wherever the page gives both: MailerLite Comfort uses its yearly-billing $17.10 (monthly $19); Podia Mover/Shaker are $42/$84 yearly-billed and $49/$99 monthly; Skool’s yearly prices were not captured so monthly is used in both views.
Patreon is modeled at the single 10% rate the page shows. Legacy plans and Patreon’s processing, currency-conversion and payout rates are not on the captured page and are not modeled.
Mailchimp and MailCheap are excluded from the calculator: they are priced by contacts or by emails sent, and neither saved page shows a revenue share or paid-subscription price to put on a take-rate axis. They are explained in guides instead.
Teachable’s 0% fee on Builder/Growth/Custom is conditional on using Teachable Payments per its FAQ; the model assumes that route.
Kit Creator is modeled at $32.50 a month: its $390 yearly invoice divided by 12. Kit displays a rounded $33.
Annual and monthly prices: newsletter prices were read in the yearly-billing view; course prices can be toggled.

Calculator input limits

The calculator rejects blank, negative, fractional-count and out-of-range entries instead of substituting a default. Documented ranges: paying subscribers and monthly sales 0–1,000,000 whole numbers; price per subscriber and per-payment fee 0–100,000; course revenue 0–100,000,000; card rates 0–100%. It also suppresses totals and rankings when a derived value is not finite or when course revenue and sales contradict each other. Invalid entries show an inline message and mark the field with aria-invalid.

Calculator input limits

The calculator rejects blank, negative, fractional-count and out-of-range entries instead of substituting a default. Documented ranges: active members 0–1,000,000 whole numbers; average dues 0–100,000; card share and hypothetical rates 0–100%; hypothetical per-payment fee 0–100. It also suppresses totals and rankings when a derived value is not finite. Invalid entries show an inline message and mark the field with aria-invalid.

Editorial responsibility and corrections

Responsibility: the site operator checks each displayed price against the vendor’s own page and records the checked date. No third-party price source is used as a vendor fact.
Cadence: checks are manual and event-driven (reported correction, visible change or next review). No fixed schedule or automatic refresh is promised.
Corrections: verified errors update the value and checked date; unverifiable points remain labeled unknown. The route is Contact & corrections (address pending).
Change history: material changes are dated on Updates.

Known limits (visible on purpose)

Plan prices are read at one list size (1,000 subscribers). Larger lists cost more.
International cards, currency conversion, taxes, refunds, chargebacks and disputes are not modeled.
Teachable’s own processing rate and Thinkific’s gateway fees were not on the captured pages (see price table); the first is assumed and tagged, the second is not modeled.
Not covered: Circle, Mighty Networks, Memberful. Buttondown is listed but not priced (its tier prices were not in the saved page).
Details a vendor’s saved page does not show (for example Skool’s processing treatment, Patreon’s processing rates, Buttondown’s tier prices, Mailchimp’s post-promo prices) are left out or labeled, never filled in.
The research behind this site shows market signals (search demand, public discussion), not guaranteed traffic or revenue. Third-party anecdotes (forum and social posts) were not used as price sources.

Evidence ledger

Raw page captures from October 24, 2026 and October 25, 2026 are stored with SHA-256 hashes in the project evidence folder; the table links on the price table point to the live vendor pages, which may have changed since.

Out of scope in this site

Affiliate programs, sponsorships, advertising, lead generation and any revenue for this site: none exist, none are claimed, and none have been verified or applied for. The site uses no analytics or newsletter signup. Correction and vendor-suggestion forms are hosted by FormRobin when their links are published on Contact & corrections; they do not add anyone to a mailing list. A sitemap is published; no search-engine submission is claimed.