EPD GUIDE · TIMELINE

How Long Does an EPD Take?

An EPD timeline cannot be given as a single number, and the stage that decides it is almost always data collection. The process starts with scope and PCR selection, continues through data collection, LCA modelling and report preparation, and ends with independent verification and publication by the programme operator. Verification and publication timing depend on the operator's rules and how complete the file is.

İpek Göktaş Kalkan · Independent EPD Verifier & LCA Consultant · Last reviewed: 7 September 2026

Key points

Data collection is the single biggest driver — not modelling, and not verification.
Verification duration is not a regulatory rule; it depends on file completeness, the number of comment rounds and the operator's own rules.
Starting on the wrong PCR does not delay a stage — it restarts the project.
In most projects the factory team's availability matters more than the consultant's speed.
Publication varies by operator and should be planned as a separate item at the end.

The stages, and what sets the length of each

The table below promises no durations. It shows what stretches or shortens each stage — the right-hand column is the one to plan against.

Stage	What happens	What sets its length
1 · Scope and PCR selection	Which product(s), which site, which PCR, which programme operator	Whether the product sits between two PCRs; how clear the target market is
2 · Data collection	Recipe, energy, production volumes, waste, transport, allocation basis	The state the data is already in and the factory team's availability — the decisive stage
3 · LCA modelling	Model setup, background dataset selection, calculation	Number of products and variants, process complexity, allocation in multi-product sites
4 · Interpretation and reporting	Interpretation, sensitivity, LCA report and EPD draft	The operator's format requirements; number of products
5 · Independent verification	Third-party review, comments, revision	How complete the file is on arrival and the number of comment rounds
6 · Publication	Registration and publication by the programme operator	The operator's own process and queue

Stages 5 and 6 are not under your control; leave separate room for them when planning.

Why data collection decides the schedule

Modelling and reporting are predictable work once the inputs are complete. The uncertainty sits almost entirely on the data side: which reference year is used, how energy consumption is attributed to the product, whether the recipe changed during the year, whether supplier information is traceable.

In practice we see two extremes. In a factory that keeps production data in order, data collection closes in a single round with the right template. In a factory where data has to be assembled from scratch, that one stage can take longer than the rest of the project combined.

Choosing the reference year. Items belonging to different years is one of the most common verification findings — and it means going back.
Attributing energy to the product. If only a site total exists, establishing the allocation basis takes additional time.
Supplier data. Where precursor information is needed, the schedule becomes dependent on how fast suppliers respond.
Getting the template right. When it is clear from the start which item is needed in which format, the factory team collects it once.

Verification and publication: the part you do not control

Verification duration is not a regulatory rule. How long it takes depends on the readiness of the file, the number of comment rounds, the scope and the programme operator's own rules. That is why no number of days or weeks is given on this page.

Speaking from our own verification practice: a complete file usually closes within a few weeks; with an incomplete file, each additional comment round extends the schedule noticeably. That is an observation, not a commitment.

Publication must be planned separately: work does not end when verification does — the declaration still has to be registered and published by the programme operator, and that step runs on the operator's timing.

Planning note

If you have to meet a tender or customer deadline, leave separate room for verification and publication when planning backwards. Neither step runs at your pace.

What genuinely shortens the schedule

1Decide PCR and operator at the very start — A study built on the wrong PCR is rebuilt during verification — a single decision doubling the whole timeline.
2Build the data-collection template properly — Which item, which unit, which source, which year — when that is clear upfront, the factory team collects it in one pass.
3Fix the reference year — Keep every item in the same period; changing the year later means rebuilding the model.
4Settle the multi-product strategy upfront — Adding products after the scope is fixed means rebuilding the data structure.
5Send a complete file to verification — A file that closes in the first round finishes weeks ahead of one that stretches across three.
6Put publication in the plan — Verification approval and a published EPD are not the same day.

A verifier's perspective

On the verification side, delays almost never come from calculation errors. The most frequent causes, in order: inconsistent data years, allocation without a written justification, background dataset selection that is not explained, and a module the PCR requires being left out.

What these have in common is that all of them originate months earlier, in decisions taken during data collection and model setup. The moment you have the best chance of saving the schedule is the start of the project — not the verification stage.

Common scheduling mistakes

Starting too close to the deadline. Data collection cannot be compressed; compressing it multiplies assumptions, which come back at verification.
Starting modelling with the PCR decision deferred. This produces the most expensive and longest rework.
Treating verification and publication as one step. They are separate processes, and neither runs at your pace.
Not accounting for the factory team's time. In a busy production season, data collection stretches.
Adding products mid-project. A scope change rebuilds the data structure and the model.
Starting supplier-dependent items late. If precursor information is needed, send the request on day one.

Frequently asked questions

How long does an EPD take?

A general figure would be misleading. The main driver of the total schedule is data collection: in a factory that keeps production data in order the process is noticeably shorter, and where data must be assembled from scratch it is longer. Verification and publication timing depend on how complete the file is and on the programme operator's rules.

How many weeks does verification take?

There is no regulatory rule for this; duration depends on the completeness of the file, the number of comment rounds, the scope and the operator's rules. In our own practice, a complete file usually closes within a few weeks — an observation from practice, not a commitment.

What stretches the process most?

In order: data collection starting unprepared, a study built on the wrong PCR being redone at verification, inconsistent reference years, and supplier data arriving late.

How can I shorten it?

Decide scope and PCR at the start, build the data-collection template properly, fix the reference year, settle the multi-product strategy upfront and send a complete file to verification. Those five steps save more time than anything that can be done later.

Is the EPD published once verification is done?

No. After verification the declaration still has to be registered and published by the programme operator. That step runs on the operator's timing and should be planned as a separate item.

Sources and basis

This page contains no duration commitments. The stages reflect the general EPD process under ISO 14025 and EN 15804+A2; how verification and publication run is always determined by the relevant programme operator's rules.

Last reviewed: 7 September 2026

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