Yes, you can display the payment summary of your online order form in real-time. This means your form users will no longer need to press the Calculate button in order to view the amount they have to pay and the taxes or discounts applied by you.
Go the Settings → Payments section of your form and scroll down to Summary and Discounts → Settings. Tick the option Show real-time payment summary on form and you are set. The payment summary will be automatically displayed on top of the form. By default, it will be folded and can be expanded on click.
If you are using another version, check out this article with the same subject.