CO2 Performance Ladder levels and tiers
The CO2-Prestatieladder (CO2 Performance Ladder) has two classifications that exist side by side in 2026. The older handbook 3.1 has five levels (1 to 5). The new handbook 4.0, which SKAO (the Dutch foundation that manages the CO2 Performance Ladder) published on 14 January 2025, replaces those levels with three tiers. Which one you need depends on what the tender asks for. Until the transition is complete, clients often accept both.
This is exactly the point where many companies get confused. On this page, we set both classifications side by side, explain the transition arrangement , and help you choose the right level for your step-by-step plan.
Handbook 4.0 has tiers, not levels. Anyone who says 4.0 has five levels is confusing the two versions. In June 2026, both classifications are valid in tenders.
The five levels of handbook 3.1
The older handbook 3.1 divides the ladder into five levels. Levels 1 to 3 cover your own organisation. Levels 4 and 5 also look at your chain: suppliers, subcontractors and the use of your products.
| Level | Focus | Scope |
|---|---|---|
| 1 | First insight into your emissions | Scope 1 and 2, own organisation |
| 2 | Insight plus first reduction targets | Scope 1 and 2, own organisation |
| 3 | Demonstrable reduction and communication | Scope 1 and 2, own organisation |
| 4 | Reduction together with your chain | Scope 1, 2 and 3 (chain) |
| 5 | Frontrunner in chain collaboration | Scope 1, 2 and 3 (chain) |
In practice, level 3 is the most requested entry level in tenders. A contractor that maps only its own vehicle fleet and office is often at level 3. All requirements and documents per perspective are on the CO2 Performance Ladder level 3 page. For what the highest level asks, from scope 3 quantification to the result obligation, read the CO2 Performance Ladder level 5 page. The same applies to the two levels in between and below: read the requirements of level 2 and the requirements of level 4, with the scoring guidelines from handbook 3.1.
The three tiers of handbook 4.0
Handbook 4.0 merges the old levels into three tiers and raises the bar. The idea: less administration, more real reduction. A tier 4 is under development for absolute frontrunners, but it is not yet available.
| Tier | What it requires | Comparable with 3.1 |
|---|---|---|
| Tier 1 | Reduce CO2 in your own organisation (scope 1 and 2) | Roughly levels 1 to 3 |
| Tier 2 | Reduce CO2 with the chain, plus a climate transition plan and value chain analysis | Roughly levels 4 and 5 |
| Tier 3 | A star on the horizon: zero emissions on scope 1, 2 and 3 towards 2050 | Beyond any level of 3.1 |
Tier 1 is stricter than the old level 3. You must not only show insight, but also demonstrate concrete reduction in your own company. Tier 2 introduces new requirements, such as a value chain analysis, which maps the emissions of your whole chain.
What applies in 2026?
In June 2026, both handbooks run side by side. SKAO’s transition arrangement gives everyone time to switch. The most important dates are listed below.
| Date | What changes |
|---|---|
| 14 July 2025 | First 4.0 audits possible |
| 1 July 2026 | Rijkswaterstaat (Dutch national public works agency) applies 4.0 in new civil engineering (GWW) tenders |
| 14 January 2027 | No new 3.1 audits possible |
| January 2028 | Last 3.1 certificates expire (valid for a maximum of 3 years) |
Do you have a 3.1 certificate now? It remains valid until January 2028 at the latest. So you do not need to switch in a hurry. If you are starting now, 4.0 is usually the logical choice, because 3.1 is being phased out.
Always check the tender document. Some clients explicitly ask for a 4.0 certificate, while others still accept 3.1. Rijkswaterstaat moves over to 4.0 from 1 July 2026.
Which level do you need?
The short answer: the level that the tender requires. Check the tender document for which level or tier is asked for, or which tender advantage is linked to which level. Often, level 3 or tier 1 is enough to take part.
If you want the maximum tender advantage, a higher level pays off. But a higher level also takes more work and money. Weigh the extra chance of winning against the costs. For most SMEs (MKB, small and medium-sized enterprises), tier 1 is the sensible starting point.
Have you determined your level? Then read on about the requirements that come with it, or start with the step-by-step plan.