Standards · 8 min read

What Is ISO 20121? A Plain-English Guide for Event Organizers

If you've googled "sustainable event certification," you've almost certainly run into ISO 20121. It's the international standard for sustainable event management, and it's also the reason many organizers assume certification means months of paperwork and a consultant's invoice. Here's what it actually is, what certification really involves, and how to decide whether it fits your event.

The short version

ISO 20121 is a management-system standard, not a scoring rubric. It doesn't tell you how many recycling bins to buy or what your carbon footprint should be. Instead, it asks whether your organization has a repeatable system for managing the sustainability of its events: a policy, clear responsibilities, goals you measure, suppliers you've assessed, and a habit of reviewing what worked and improving the next time.

That's its strength: it builds sustainability into how you run events, not just what happens at one of them. It's also why it can feel heavy: the standard certifies your management system, so the audit focuses on documentation, processes, and governance as much as on-the-ground outcomes.

Where it came from

The standard grew out of the sustainability program for the London 2012 Olympic and Paralympic Games, which used the British standard BS 8901. That work was internationalized as ISO 20121, first published in 2012 and updated in 2024. Today it's used by major venues, organizing committees, agencies, and corporate event teams around the world.

What certification actually involves

ISO 20121 certification is carried out by accredited third-party certification bodies, the same audit firms that certify companies against ISO 9001 and ISO 14001. In practice that means:

• Documentation: a written sustainability policy, objectives with targets, procedures, and records showing you follow them.
• Stakeholder engagement: evidence that you've considered the people affected by your event: attendees, staff, suppliers, the local community.
• Measurement: a way of tracking the issues that matter (energy, waste, travel, procurement) and acting on the results.
• Audit and surveillance: an initial certification audit, followed by regular surveillance audits, typically an annual cycle for as long as you keep the certificate.

Costs and timelines vary by organization, but for a small team the realistic picture is: significant preparation, an external audit, and an ongoing commitment to keep the management system alive between audits. For global brands and major venues, that investment makes sense. For a 300-person conference or a community festival, it often doesn't, at least not yet.

Who ISO 20121 is right for

ISO 20121 shines when you need it for procurement: enterprise clients and public-sector contracts increasingly ask suppliers and venues for it, and for large recurring events it pays for itself in institutional credibility. If your goal is different, proving to attendees, sponsors, and your community that your event genuinely measures up, a lighter, aligned certification gets you most of the benefit without the management-system overhead.

A simpler path that's aligned with the standard

Greening the Experience was built for that middle ground. Our framework mirrors the substance of ISO 20121: policy and leadership, waste, carbon and energy, supplier sustainability, attendee engagement, innovation, and financial alignment. But we score your event directly, not your paperwork. You calculate your carbon footprint, complete a sustainability assessment, gather co-auditor feedback, upload evidence, and receive a verified score that maps to a tier, from Sprout through Canopy.

Many organizers use it as a stepping stone: certify your event now, and if a client later demands ISO 20121 certification of your organization, you'll already have the evidence trail, measurements, and documented practices the audit will ask for.