If you are a teacher or a student you can extend for free your fully featured trial version up to five years (teachers) / one year (students). The trial extension is provided to support teaching and research and its use for commercial benefit outside of a class project is prohibited.
To get your trial extension key you need to send an email to firstname.lastname@example.org providing the following information:
Please note that only a school-issued email address will be accepted. A school email address may include .edu, .k12, or other email domains sponsored by educational institutions. Additional information may be required.
To enter your trial extension, go to MS Excel > About/Enter license key > Other options > Extend your trial. This option will only be available when your previous trial version is expired.
After your trial extension expires you can request a new trial extension key as long as you still meet the academic requirement.