Platform comparison
Kit (formerly ConvertKit) vs Substack: Which Is Better in 2026?
Kit, formerly known as ConvertKit, and Substack can both work for newsletter creators, but they are built for different types of businesses. If you are comparing ConvertKit vs Substack, the biggest differences are fees, automation, audience ownership and how each platform helps you monetize. Substack focuses on simple publishing and paid subscriptions, while Kit gives creators more control over email marketing, automations and audience management.
Last reviewed: September 2026
Quick answer
Choose Substack if you want the easiest possible setup and do not mind paying a percentage of your subscription revenue.
Choose Kit if you want more control over your email list, automations and creator business as it grows.
ConvertKit (Kit) vs Substack at a glance
| Feature | Kit | Substack |
|---|---|---|
| Free plan | Yes | Yes |
| Paid newsletter transaction fees | 3.5% + $0.30 per USD transaction, including card processing | 10% platform fee + payment processing |
| Advanced email automations | Strong | Limited |
| Built-in discovery | Limited | Strong |
| Best for | Creator businesses and email marketing | Simple publishing and paid newsletters |
ConvertKit vs Substack fees: how much do you actually keep?
The biggest financial difference between Kit and Substack appears once you start charging readers. Substack currently takes 10% of paid subscription revenue, before payment processing. Kit Commerce charges 3.5% + $0.30 per USD transaction, with card processing included.
Kit Commerce is available on the Free plan, so you can start a paid newsletter without first paying a monthly software fee. Substack is also free to publish on, but its percentage-based fee grows directly with your paid revenue.
Real fee examples: 100 paid subscribers
To make the comparison concrete, assume you have 100 paid subscribers billed once per month. Kit's estimates below use its current USD fee of 3.5% + $0.30 per transaction. Substack shows its 10% platform fee only; Stripe processing is additional.
| Price per subscriber | Monthly revenue | Kit estimated fees | Substack platform fee | Difference before Stripe |
|---|---|---|---|---|
| $5 | $500 | ~$47.50 | $50 + Stripe | Kit lower by ~$2.50 before Stripe |
| $10 | $1,000 | ~$65 | $100 + Stripe | Kit lower by ~$35 before Stripe |
| $20 | $2,000 | ~$100 | $200 + Stripe | Kit lower by ~$100 before Stripe |
| $50 | $5,000 | ~$205 | $500 + Stripe | Kit lower by ~$295 before Stripe |
These examples assume 100 monthly USD transactions. Substack payment-processing fees are additional and vary by payment method, country and currency.
Why revenue changes the answer
At $500 per month, the platform-fee difference is small before Stripe. At $5,000 per month, Substack's 10% platform fee alone reaches $500 every month, while the same 100 monthly transactions would cost roughly $205 through Kit Commerce.
That is why paid newsletter creators should compare fees using their own subscriber count and subscription price instead of choosing only by headline monthly pricing.
Use the NewsletterFit Substack Fee Calculator to test your own numbers.
Fees reviewed in September 2026 using official provider documentation.
Sources: Kit pricing · Kit Commerce · Substack fees
When Kit makes more sense
Kit becomes especially attractive if your newsletter is part of a larger creator business. It gives you more tools for segmenting subscribers, creating email sequences and automating how people move through your audience.
That can make Kit a better fit for creators selling courses, products, memberships or services in addition to a newsletter.
When Substack makes more sense
Substack is appealing if your priority is to start publishing quickly without dealing with many technical or marketing decisions.
Its built-in network and discovery features can also help writers who want their publication to live inside the Substack ecosystem.
Not sure which one is cheaper for you?
Enter your subscriber count, paid subscribers and monthly price into the NewsletterFit calculator to compare estimated platform costs based on your own numbers.
Compare newsletter platforms →ConvertKit vs Substack FAQ
Does Substack take 10% of subscriptions?
Yes. Substack currently charges creators a 10% platform fee on paid subscription transactions. Payment-processing fees from Stripe are additional.
Can you sell paid newsletters on Kit's free plan?
Yes. Kit Commerce is available on the Free plan. USD sales currently cost 3.5% + $0.30 per transaction, including card processing.
Is ConvertKit now called Kit?
Yes. ConvertKit rebranded to Kit. People still search for ConvertKit, so NewsletterFit uses both names where helpful.
Which platform gives creators more automation?
Kit provides deeper email segmentation, visual automations and sequences. Substack focuses more heavily on publishing, simplicity and built-in discovery.
Bottom line
Substack is usually easier for creators who want a simple publishing experience. Kit is generally the stronger option for creators who want more control, automation and flexibility as their business grows.
Pricing and features can change. Always verify current pricing and product details directly with each provider before making a final decision.
Try Kit →Affiliate link. NewsletterFit may earn a commission at no extra cost to you.
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