Take user to checkout before upgrading subscription or increasing units

Question

I have 3 packages. Free, basic, and premium. They are worth $0.00, $100.99, and $200.99 per year respectively. They are sold on the basis of quantity. For example, you can have 5 basic subscriptions. The user can upgrade number of quantity and plan any time.

My question is let's say someone is on basic plan with 5 subscriptions. And midway to their pricing period, the person decides to increase the number of quantity to let's say 10. Then, how can I collect the amount the user has to pay for the extra 5 units for six months?

From the very little knowledge I have, stripe charges them from the next billing period. So how can I collect the 5 * (100.99 / 6) (divide by 6 for six months)?

Also, If the user chooses to upgrade, how can I handle the payment for that? Let's say user goes from basic to advance mid-way the billing period. How can I charge the money instantly for the upgrade?

Right now I'm thinking that I should calculate the amount required to be paid and take the user to checkout and pay once. After payment is successful, update the subscription quantity or schedule as required. Is this approach appropriate?

Thank you very much for helping in advance.

Answer 1

You can tailorupgrade behavior with prorations . I recommend reading those two links and then also taking a peek at this documentation .