How do I upgrade to a larger monthly plan?

Upgrade is immediate with prorated billing. Quick steps:

1. Open Buy Credits in the sidebar → Monthly Plans tab.
2. Pick a tier larger than your current one. The card shows "Upgrade: Pay the difference today".
3. Pick a payment method, click the upgrade button.
4. The preview modal shows the prorated amount and new next-billing-date. Click Confirm & Pay.

Credits land immediately, billing cycle resets to 30 days from the upgrade. The full breakdown including the proration math lives at upgrade your subscription.