Billing & tiers

C3NTR offers three tiers so you can start free and grow at your own pace. Every tier includes the core knowledge library. Paid tiers unlock extra features as your school needs them.

The three tiers

• Seed (free forever) — Up to 30 members, 500 MB storage. All core features included: articles, glossary terms, tags, video and audio, search, favourites, and branding.
• School — £39/month, or £32/month billed annually. Up to 150 members, 5 GB storage. Everything in Seed, plus push notifications and engagement analytics.
• Academy — £69/month, or £57/month billed annually. Unlimited members, 10 GB storage. Everything in School, plus multi-instructor publishing.

Annual billing saves roughly 18% compared to paying monthly.

Feature gates

Two features require the School tier or above:

• AI writing assistant — Generate article drafts with help from AI.
• Analytics — See the dashboard with member activity, views, open rates, and reading trends.

Articles, glossary terms, video, and audio are available on every tier, including the free Seed plan — what changes between tiers is how much storage you have and how many members can join.

If you try to use a gated feature on the Seed tier, you will see a prompt explaining which plan unlocks it. No content is lost — the feature becomes available the moment you move to a paid plan.

Upgrade your plan

See your current plan

Two places in the app show the school's current plan at a glance:

• User menu — open the menu (tap your avatar on Home, or swipe in from the right edge of any tab). The school card shows a pill with the plan name (for example, Academy plan) below the school's discipline.
• School details — scroll to the bottom of the School Details screen. The plan card names your current plan and has a quiet Manage your plan link straight to the plan management screen.

Manage your subscription

From Settings > Billing, tap Manage subscription to open the Stripe billing portal. There you can:

• Switch between monthly and annual billing.
• Update your payment method.
• View and download invoices.
• Cancel your subscription.

Storage add-ons

If you reach your storage limit on a paid plan, you can purchase additional storage from the billing portal. Storage add-ons are not available on the free Seed tier — upgrade to School or Academy first.