No provision of the German Accessibility Strengthening Act (Barrierefreiheitsstärkungsgesetz, BFSG) is quoted more eagerly and read less carefully than Section 17. In meetings it sounds like an emergency exit: if accessibility gets too expensive, you simply invoke disproportionate burden. The statute says the opposite of relief. Section 17 shifts the burden of proof entirely onto the economic operator. He must carry out the assessment himself, calculate it against the criteria of Annex 4, document it, retain it for five years (Section 17(2) BFSG) and produce it for the competent authority on request. An informal assertion carries no weight in this construction. This article walks through the actual arithmetic of Annex 4, separates Section 17 cleanly from the microenterprise rule, explains why the exemption is almost always divisible and covers individual functions rather than a whole site, and provides an outline that lets the documentation survive an inspection.
Section 17 is not an exemption, it is a burden of proof
The wording is unremarkable and consequential at once: accessibility requirements apply only insofar as compliance does not impose a disproportionate burden on the economic operator within the meaning of Annex 4, and the operator carries out the assessment himself (Section 17(1) BFSG). The misunderstanding lives in exactly that sentence. Because nobody approves the exemption in advance, it looks easy to obtain. In truth only the prior check is missing. The check itself does not disappear, it merely moves to a later point in time and then takes place under worse conditions.
The self-assessment does not stay in-house either. Anyone invoking the exemption must inform the competent market surveillance authority without delay, in every member state where the product is placed on the market or the service is provided (Section 17(5) BFSG). The authority subsequently reviews the assessment that was made (Section 21(3) and Section 28(3) BFSG, BMAS guidelines on the BFSG). For products and services under the BFSG, the 16 German federal states (MLBF) have set up a joint market surveillance body as a public-law institution in Magdeburg; the act has applied since 28 June 2025 (BMAS guidelines on the BFSG). What a company records in an internal note is therefore potentially a document that an authority will later read and evaluate.
This inverts the usual expectation. An exemption does not come into being because you invoke it, but because you can substantiate it. If the reasoning collapses under inspection, the exemption retroactively never existed. What remains is a service that failed to meet the requirements. That distinction is not academic: offering or providing a non-accessible service contrary to Section 14(1) BFSG falls within a fine range of up to EUR 100,000 (Section 37 BFSG), while breaches of information and disclosure duties can be fined up to EUR 10,000 (Section 37 BFSG). The other routes enforcement can take are set out in the article on BFSG enforcement and legal risks.
The exemption arises from evidence, not from invocation
The three criteria of Annex 4
Annex 4 to the BFSG names neither a percentage limit nor a euro amount. It names three ratios (Annex 4 to the BFSG) that together carry the overall assessment. Anyone calculating only one of them has not performed the assessment but produced a metric. The same three criteria appear at European level in Annex VI to Directive (EU) 2019/882, to which Article 14 of the directive refers for the assessment.
| Criterion (Annex 4 to the BFSG) | What is set in relation | Reference figure that must be evidenced |
|---|---|---|
| Criterion 1: cost ratio | Net cost of accessibility to total costs | Total operating and investment costs for manufacture, distribution, import or provision |
| Criterion 2: cost-benefit weighing | Estimated costs and benefits for the economic operator against the estimated benefit for people with disabilities | Frequency and duration of use of the specific service |
| Criterion 3: turnover ratio | Net cost of accessibility to net turnover | Net turnover of the economic operator, same cost base as criterion 1 |
What is missing is striking: a figure above which a burden becomes disproportionate. That is not an editorial oversight but the system at work. The Federal Ministry of Labour and Social Affairs is empowered to specify and supplement the criteria of Annex 4 by statutory instrument with the consent of the Bundesrat and in agreement with further ministries (Section 17(6) BFSG). As long as no such specification translates the three ratios into fixed limits, the assessment remains a reasoned case-by-case calculation. In practice that means there is no quota to hide behind, but equally none that automatically catches you. There is only the calculation and how well it can be followed.
Three criteria, no threshold
The arithmetic: what belongs on the cost side
The most common craft error in Section 17 documentation is a cost side that is too narrow. A developer day rate gets counted, and that is that. Annex 4 to the BFSG is considerably more precise and distinguishes two groups: one-off organisational costs and recurring production and development costs (Annex 4 to the BFSG). Both groups belong to the net costs that criterion 1 and criterion 3 put into a ratio.
Annex 4 expressly counts the following among the one-off organisational costs:
- Specialist staff: employing personnel with expertise in the field of accessibility.
- Training and skills: training existing personnel and building accessibility competence in-house.
- New processes: developing new procedures to build accessibility into product development or service provision.
- Guidelines: producing instructions and guidelines for accessibility.
- Learning the legal framework: the effort of familiarising yourself with the relevant legal provisions.
On top of these come the recurring costs of production and development, which arise because accessibility runs continuously rather than being bought once:
Planning and design
The effort of planning and designing the accessibility features themselves, meaning the conceptual work that precedes implementation (Annex 4 to the BFSG).
Adapting processes
Changes to production and development processes needed so that accessibility does not have to be bolted on afterwards (Annex 4 to the BFSG).
Testing
The effort of testing products and services for accessibility, including the procedures used to do so (Annex 4 to the BFSG).
Documentation
Producing the documentation that belongs to accessibility, as well as the Section 17 assessment itself (Annex 4 to the BFSG).
The prefix is decisive. Annex 4 speaks of net costs, not gross costs. What is meant are the costs arising solely from compliance with the accessibility requirements. A relaunch that was planned anyway, a legacy system replacement that was due anyway, or a form redesign that was scheduled anyway does not belong in this calculation at full value; only the additional share caused by the requirements counts (project experience). Precisely this separation makes the assessment demanding, because it forces you to allocate effort per requirement instead of quoting a lump sum. How that separation feels in real projects is shown by the cost analysis in the article on the cost and benefit of an accessibility audit.
External funding rules the exemption out
The other side of the equation: the benefit
Criterion 2 is the part most documentation leaves out because it is uncomfortable. What is required is not only a cost estimate but the comparison of the estimated costs and benefits for the economic operator with the estimated benefit for people with disabilities, expressly taking into account the frequency and duration of use of the specific service (Annex 4 to the BFSG). A calculation that knows only costs is therefore structurally incomplete, no matter how carefully those costs were determined.
The scale of the benefit side cannot be argued away. At the end of 2025, a good 7.8 million people with severe disabilities lived in Germany, equal to 9.4 percent of the population (Federal Statistical Office). The age distribution is telling for digital services: 45 percent of them, or 3.5 million people, belonged to the 55 to 74 age group, and a further 34 percent, or 2.7 million, were 75 or older (Federal Statistical Office). That is officially recognised severe disability and therefore a lower bound: temporary impairments, age-related decline in vision or situational limitations are not included.
For the assessment under criterion 2 this produces an awkward asymmetry. The more central and the more frequently a function is used, the higher the benefit and the harder the exemption is to justify. An ordering process, an appointment booking or a contact form are functions with high usage frequency; they sit at the centre of the service. Anyone claiming disproportionate burden precisely there is arguing against their own usage statistics. Why the order completion in particular is so rarely a candidate for exemptions is shown by the article on accessible checkout in e-commerce.
An assessment under Section 17 that fills in only the cost side is not half an assessment. It is none at all, because the second criterion of Annex 4 expressly requires the counter-calculation.
Distinction: microenterprise is a different legal basis
In conversation the two forms of relief regularly merge into a single argument: "we are small, so this is disproportionate for us." Legally these are two separate instruments with different bases, different reach and, above all, different duties to cooperate. The microenterprise rule excludes microenterprises that offer or provide services from the scope of the act (Section 3(3) BFSG); at European level this corresponds to Article 4(5) of Directive (EU) 2019/882. Microenterprises are enterprises with fewer than 10 employees that either achieve an annual turnover of at most EUR 2 million or whose annual balance sheet total is at most EUR 2 million (BMAS guidelines on the BFSG).
| Feature | Microenterprise rule (Section 3(3) BFSG) | Disproportionate burden (Section 17 BFSG) |
|---|---|---|
| Legal basis | Section 3(3) BFSG, Article 4(5) of Directive (EU) 2019/882 | Section 17 BFSG with Annex 4, Article 14 of Directive (EU) 2019/882 |
| Connecting factor | Size of the enterprise, regardless of the individual case | Ratio of cost, benefit and turnover in the specific case |
| Reach | Services only, products remain covered | Products and services, but only individual requirements |
| Documentation | No assessment under Annex 4 required | Document the assessment and retain it for five years |
| Notification duty | No notification to the authority | Inform the authority without delay (Section 17(5) BFSG) |
| Dynamics over time | Status ends as soon as the threshold is exceeded | Reassessment at least every five years and on any change |
The table makes the practical difference visible. The microenterprise rule is a scope exclusion that either applies or does not; it demands no calculation. Section 17 is the opposite: a case-by-case decision that does not exist without a calculation. Anyone wanting to check the thresholds and the limits of the scope exclusion properly will find the detail in the article on the BFSG exemption for microenterprises. Important for the order of analysis: Section 17 only becomes relevant once the scope exclusion does not apply.
Special case: microenterprises dealing with products
Why the exemption is almost always divisible
The most widespread misconception is the all-or-nothing one. In fact Section 17(1) BFSG already expresses divisibility through the words "only insofar as", and the BMAS guidelines make it explicit: a disproportionate burden may exist where compliance represents an additional excessive organisational or financial burden and where it would not be reasonably possible for the economic operator to apply one or more of the accessibility requirements in full (BMAS guidelines on the BFSG). The reference unit is therefore the individual requirement, not the company and not the website.
This makes the blanket invocation fall apart in practice. "Our website is covered by Section 17" is not a statement Annex 4 recognises. What can be calculated is only this: this specific requirement for this specific function causes net costs of this amount, measured against these reference figures, at this estimated benefit. The same website can therefore have requirements that are met, others that are deferred and still others assessed as disproportionate. The requirements themselves come from the harmonised standard described in the article on EN 301 549, the standard behind the BFSG.
- More likely to hold: a single, rarely used legacy function whose accessible redevelopment is out of proportion to its usage volume, with documented usage frequency as evidence.
- More likely to hold: an extensive archive of historical documents whose complete reworking may be assessed differently from the documents currently offered, as the practice of accessible PDF documents shows.
- Hardly tenable: the ordering or booking process, in other words the function with the highest usage frequency and the greatest benefit within the meaning of criterion 2.
- Not tenable: the blanket invocation covering an entire website or the entire offering, because it names no requirement and therefore has no reference figure.
- Not tenable: an invocation for areas where external funding was drawn on to improve accessibility (Section 17(4) BFSG).
Divisibility is not a hardship, incidentally, but an opportunity. It allows an honest prioritisation to be documented: what matters becomes accessible first, what is peripheral receives reasoned and time-limited special treatment. That is exactly how a plan comes about that you can show an authority without blushing.
Time limits, reassessment and the notification duty
An assessment under Section 17 is a snapshot, not a permanent state. For service providers the act expressly prescribes repetition: anyone invoking disproportionate burden must carry out the assessment afresh for each category or type of service at least every five years, additionally on every change to the service offered, and whenever the competent authority requests it (Section 17(3) BFSG). At European level this corresponds to the five-year rhythm in Article 14 of Directive (EU) 2019/882.
- Assess: carry out the check per requirement against the three criteria of Annex 4, not as a blanket judgement on the offering.
- Notify: inform the competent market surveillance authority without delay, in every member state concerned (Section 17(5) BFSG).
- Retain: keep the documentation for five years from the last placement of a product or the last provision of a service (Section 17(2) BFSG).
- Produce: make a copy of the assessment available to the authority on request (Section 17(2) BFSG).
- Reassess: as a service provider at least every five years, on any change to the service and at the authority's request (Section 17(3) BFSG).
The reassessment duty has a side effect that is rarely thought through: it works against the exemption. The net cost of accessibility tends to fall, because competence grows in-house, processes stay established once built and components become reusable. A calculation that narrowly supported disproportionality in 2026 may flip by 2031 without anything about the offering having changed. The yardstick keeps moving too, as a look at the status and timeline of the WCAG 3 draft shows. Anyone planning the exemption as a permanent solution is planning against time. Continuous observation rather than a one-off check is therefore the more realistic approach, as reflected in accessibility monitoring.
An outline that survives inspection
The act prescribes no format for the documentation. It does prescribe that the documentation reflects the assessment against the criteria of Annex 4 and can be produced on request. From that requirement an outline can be derived that survives an official query, because it ties every claim to a reference figure:
- Subject and scope: which service or product is being assessed, which category or type within the meaning of Section 17(3) BFSG, with a cut-off date and a responsible person.
- Legal basis and yardstick: reference to Section 17 BFSG, the criteria of Annex 4 and the applicable requirements, as a rule via EN 301 549.
- Findings per requirement: the audited actual state with the requirements that are specifically not met, named and located rather than summarised.
- Net costs, one-off: specialist staff, training, new processes, guidelines and learning the legal framework, each with its derivation (Annex 4 to the BFSG).
- Net costs, recurring: planning and design, process adaptation, testing and documentation, separated by requirement (Annex 4 to the BFSG).
- Reference figures: total operating and investment costs plus net turnover, stating the source in your own accounts and the reference period.
- Benefit estimate: the estimated benefit for people with disabilities taking frequency and duration of use into account, supported by your own usage data.
- Result per requirement: the conclusion separated by requirement, with reasoning why the criteria taken together do or do not hold.
- Validity and updating: the time limit, the reassessment date, the triggers for an early reassessment, plus the date and addressee of the notification under Section 17(5) BFSG.
Points three to five are the breaking point. Without an audited finding per requirement there is no clean allocation of costs, and without that allocation the cost side remains an estimate with no basis. That is exactly why the audit report is not an annex to the documentation but its precondition. Anyone still needing to sort through the requirements themselves will find the overview on the page covering BFSG requirements; how the results are communicated publicly is covered by the accessibility statement.
From assertion to a defensible calculation
Anyone reading Section 17 BFSG as a shortcut has misread it. The provision relieves nobody of effort; it merely moves the effort from implementation into proof. That can pay off where a requirement attached to a rarely used function genuinely is out of proportion. It does not pay off where the documentation ends up costing more than the implementation, which is regularly the case with manageable findings. Making that trade-off honestly, however, presupposes that both figures are known. This is exactly where most invocations of Section 17 fail: the cost side was never calculated, it was estimated.
What counts in the end
The path there does not start in the legal team but in the findings. A structured WCAG 2.2 audit delivers the cost side in the only form Annex 4 can use: requirement by requirement, with prioritised measures and the effort attached to each. Only from that does a calculation emerge that can be produced, and it frequently turns out that the route via accessible web development is shorter than the route via the exemption. Where knowledge is missing in the team, accessibility training closes the gap that Annex 4 recognises as a cost item anyway. To place your own case, a conversation about the specific audit scope is often enough.
Sources and studies