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Kit (formerly ConvertKit) vs Substack in 2026: flat fee or 10% take rate?

Substack and Kit charge for newsletter creators in fundamentally different ways. Substack takes 10% of every paid subscription dollar forever; Kit charges a flat monthly fee that scales with your total subscriber count. The answer to "which is cheaper" depends on two variables: your paid subscription revenue and your total list size. Below ~$4,000/year in paid sub revenue, Substack is the cheaper option. Above that threshold, Kit gets cheaper — until your list grows enough that Kit's tier pricing becomes the more expensive option again.

TL;DR

• Cost crossover happens around $4,000/yr in paid subscription revenue at 1,000 total subscribers. Below that, Substack is cheaper. Above, Kit Creator wins on pure cost.
• The crossover threshold rises with subscriber count. At 10K subs you need $13K+/yr in paid sub revenue before Kit becomes the cheaper option.
• Cost is rarely the right reason to pick. Kit's automation, segmentation, and commerce features are worth real money if you use them. Substack's network is worth real money in audience growth if you're in the publishing-discovery business.
• Both have free tiers but they're functionally different — Substack free is unlimited subscribers with revenue-sharing only when you go paid; Kit free is 10K subs with severely limited features.

How they charge (verified)

Substack pricing

• Free to publish — no subscription fee for Substack itself.
• 10% take rate on all paid subscription revenue, forever. Plus Stripe fees (2.9% + $0.30 per transaction).
• Custom domain: $50 one-time fee per publication. Connecting a custom domain removes you from Substack's recommendation network, sacrificing discoverability for brand control.
• No API access, no automations beyond a basic welcome email, no segmentation.
• Built-in network: Notes (social feed), recommendations engine, leaderboards, "Best of" curation.

Kit (ConvertKit) pricing

• Newsletter (free): Up to 10,000 subscribers. Heavily limited — 1 basic visual automation, no A/B testing, Kit branding can't be removed.
• Creator: $33/month annual billing ($39/mo monthly) for 1,000 subscribers. Scales with subscribers: $75/mo at 5K, $113/mo at 10K, $234/mo at 25K, $566/mo at 100K. Includes unlimited automations, sequences, 2-variant A/B testing, branding removal, integrations/API.
• Creator Pro: $66/month annual ($79/mo monthly) for 1,000 subs. Adds 5-variant A/B testing, deliverability reporting, Facebook Custom Audiences sync, newsletter referral system.
• Commerce transaction fee: 3.5% + $0.30 per transaction (for digital product sales).
• Sponsor Network: Kit takes 23.5% of sponsorship revenue. Requires 10,000+ subscribers, weekly send cadence, exclusivity.
• Kit raised prices approximately 35% in October 2025 with no grandfathering.

Feature matrix

Best for [persona]

Pick Substack if you are:

• A writer or publisher whose primary product is the writing itself, not a multi-product creator business.
• Earning less than $5,000/year in paid subscription revenue — Substack's cost is lower at small scale.
• Counting on discovery through the Substack network — Notes, recommendations, and the leaderboard genuinely drive new readers in a way no other platform replicates.
• Allergic to platform configuration — Substack works out of the box with zero decisions.
• Publishing essays, longform content, or commentary where the editorial experience matters more than the marketing stack.

Pick Kit if you are:

• Earning meaningful paid subscription revenue ($10K+/year) AND actively use automations or sequences. The flat fee + 0% subscription take pays back fast.
• Selling digital products, courses, or coaching alongside your newsletter — Kit's commerce is built in; Substack has no equivalent.
• Running a multi-product creator business that needs tagging, segmentation, and conditional logic ("if subscriber clicked the course landing page, add to nurture sequence X").
• Already on Kit and have years of segmentation + automation data you'd lose by migrating.
• Running paid acquisition through Meta Ads and want native Custom Audiences sync.

The honest crossover math

When does the cost difference actually flip?

| Total subs | Kit Creator (annual)/yr | Substack (gross sub revenue needed to equal Kit) | |---|---|---| | 1,000 | $396 | $3,960 | | 5,000 | $900 | $9,000 | | 10,000 | $1,356 | $13,560 | | 25,000 | $2,808 | $28,080 | | 50,000 | $4,224 | $42,240 | | 100,000 | $6,792 | $67,920 |

Read this as: "At [N] total subscribers, you need to be earning at least the corresponding paid-sub revenue for Kit's flat fee to become cheaper than Substack's 10% take."

Most creators we've talked to are in the left of this curve — meaning Substack remains cheaper for them. Only creators with materially monetized lists ($10K+/yr) flip into Kit-wins territory, and even then the per-year savings are often under $1,000 — small relative to the value of choosing the platform whose features and network actually fit your workflow.

Where neither cost framing matters

A few situations where the cost math is the wrong question:

• You're building a creator business with products + courses + community. Kit's commerce stack saves you stitching together 3 SaaS tools. The platform fee pays back via reduced operational overhead, not direct cost comparison.
• You write longform essays and care primarily about reaching readers. Substack's network value is enormous and not capturable on a spreadsheet. The 10% is a tax for distribution.
• You're already at $50K+/yr revenue on either platform. Migration cost (10–25% subscriber churn, manual automation rebuild) almost certainly exceeds any annual savings. Stay where you are unless the platform genuinely fails you.

Migration considerations

• Substack → Kit: Subscribers export cleanly. Paid subs need Stripe re-authorization (10–25% churn). Notes/network goes away. Automations and tagging must be set up from scratch. Substack-hosted URLs lose ranking unless you keep paying for the custom domain.
• Kit → Substack: Less common direction. CSV import works fine. Automations don't transfer (Substack doesn't have them). Tagging data is lost. Commerce products need separate handling.

Related comparisons

• Beehiiv vs Kit — Kit after its October 2025 ~35% price hike vs Beehiiv's subscriber-based pricing
• Beehiiv vs Substack — the take-rate-vs-flat-fee math from the Beehiiv side
• Best newsletter platforms in 2026 (ranked) — where Kit and Substack land in our full ranking
• Newsletter platform pricing in 2026 — interactive calculator across all major platforms
• Best free newsletter platforms — Substack's free tier is unusual; see how it compares