By Julien Sudre, Horizon Europe proposal development and project management specialist, founder of Grant360 and Innotrope.
Financial management mistakes in Horizon Europe most often arise when beneficiaries declare costs that do not meet their Grant Agreement's eligibility conditions, use the wrong cost category, or cannot demonstrate how expenditure relates to project implementation. Personnel records, procurement, subcontracting, equipment depreciation and double funding all deserve particular attention. The practical solution is to check eligibility before committing expenditure and preserve a clear evidence trail throughout the project, not to reconstruct one before an audit.
This guide focuses primarily on actual-cost Horizon Europe grants. Lump-sum grants follow different payment and reporting rules, so beneficiaries should always check their signed Grant Agreement (GA), call conditions and applicable funding model. For the broader financial framework, see How Does Financial Management Work in Horizon Europe?.
When is a cost ineligible under Horizon Europe?
A cost is ineligible when it fails the general or category-specific conditions of the GA, even if it contributed to the project. Under Article 6 of the EU Grants Annotated Grant Agreement (AGA), actual costs generally need to be incurred by the beneficiary during the action period (subject to specified exceptions), connected to the action, necessary for its implementation, identifiable and verifiable in the accounts, compliant with applicable law, and reasonable and justified under sound financial management.
Example: A partner buys laboratory supplies for an activity described in Annex 1, but the purchase is charged to a different project and no reliable allocation record exists. The scientific relevance of the supplies does not by itself establish which grant may reimburse the cost.
A cost is not automatically ineligible merely because one document is missing: the relevant question is whether the beneficiary can provide sufficient, reliable evidence satisfying the applicable rules. Conversely, a complete invoice does not make an otherwise ineligible purchase eligible.
Primary source: EU Grants Annotated Grant Agreement, Article 6.
Which personnel-cost mistakes should beneficiaries avoid?
The main personnel-cost risks are claiming unsupported time, using the wrong calculation method, misclassifying working relationships, or declaring remuneration that does not meet the applicable conditions. The evidence and calculation method depend on the personnel category and the cost option in the signed GA.
How should time worked on the project be documented?
Beneficiaries must maintain reliable records demonstrating the time personnel worked on the action, unless an applicable rule or accepted alternative provides otherwise. For standard actual-cost personnel reporting, monthly declarations of days worked or another reliable time-recording system may be used under the AGA's conditions; a universal requirement for signed daily timesheets would be misleading.
Example: A researcher contributes to two EU projects in the same month. Their records must distinguish the days attributable to each action and remain consistent with the beneficiary's other personnel and accounting records. A retrospective estimate unsupported by contemporaneous evidence creates avoidable risk.
Can all beneficiaries use the same daily personnel rate?
No. Personnel-cost calculations depend on the applicable category and funding option. Standard actual-cost calculations, approved Horizon Europe personnel unit costs, and special categories such as eligible small and medium-sized enterprise (SME) owners without a salary follow different rules. Do not apply a convenient organisation-wide rate unless it is authorised for the beneficiary and action.
Example: An institution approved to use the Horizon Europe personnel unit-cost option must follow that option's conditions for the relevant grants; another beneficiary may still report eligible actual personnel costs under the standard method.
Are consultants always subcontractors?
No. The correct category depends on the contractual relationship and the work performed. An eligible natural person working under a direct contract may fall within a personnel category if the specific conditions are met; an external company delivering an action task may be a subcontractor; a supplier providing a supporting service may fall under purchase costs. Classify the arrangement before signing the contract.
Primary source: AGA, Article 6.2.A: Personnel costs.
When does subcontracting create an eligibility risk?
Subcontracting becomes risky when a beneficiary outsources an action task without satisfying the GA's subcontracting conditions, fails to demonstrate best value for money or the lowest price where appropriate, or does not address conflicts of interest. Subcontracted action tasks should be identified in Annex 1; the AGA also explains how certain unforeseen subcontracting may be accepted without a prior amendment, subject to conditions and the granting authority's assessment.
Subcontracting a scientific task is not categorically prohibited. The relevant issues are the task's role in the action, whether subcontracting is justified and permitted, and whether procurement and documentation requirements are met. The coordinator's core responsibilities cannot simply be transferred to a subcontractor.
Example: A beneficiary contracts an external laboratory to conduct specialised tests. It should document the technical need, selection procedure, contractual scope, deliverables, invoice and acceptance of the work, and verify whether the planned subcontracting is properly reflected in the GA.
Primary source: AGA, Article 6.2.B: Subcontracting costs.
Which purchasing and procurement errors can make costs ineligible?
A purchase may be challenged when the beneficiary cannot show that it followed the applicable procurement rules, obtained best value for money or the lowest price where appropriate, avoided conflicts of interest, or bought something necessary for the action. Horizon Europe does not impose an identical tender procedure on every beneficiary and purchase; national law, institutional procedures and GA requirements must be considered together.
Example: A partner selects a familiar supplier for a substantial service contract. A single-source purchase is not automatically ineligible, but the beneficiary should retain a contemporaneous, defensible explanation of the choice and demonstrate compliance with the rules that apply to it.
Maintain the request or specification, offers or other market evidence where relevant, selection rationale, conflict-of-interest checks, contract, invoice and evidence of delivery. Avoid inventing a retrospective competition that did not occur.
Primary source: AGA, Article 6.2.C: Purchase costs.
Which travel costs are at risk of rejection?
Travel and subsistence costs must be necessary for the action, compliant with the beneficiary's usual travel practices and the applicable GA conditions, and supported by reliable records. A trip is not automatically eligible merely because a project employee attended it.
Example: A researcher attends a conference and presents project results. The programme, presentation, travel approval, invoices and evidence of participation help establish the connection to the action. An extra private weekend should not be charged to the grant unless a particular expense independently meets the eligibility rules.
Travel documentation should establish who travelled, why, when, at what cost, and how the trip supported the action. For meetings, minutes or a short mission report can complement the financial documents; they are useful evidence, not a universal standalone legal requirement.
Primary source: AGA, Article 6.2.C.1: Travel and subsistence.
Can a Horizon Europe project charge the full purchase price of equipment?
Usually, under the standard depreciation-based equipment option, only the eligible depreciation corresponding to project use and the eligible period may be declared. However, some grants or calls activate other equipment-cost options, including full-cost treatment under specified conditions. Always check the relevant GA provisions before assuming either approach.
Illustrative calculation: A EUR 40,000 instrument is depreciated over four years, used for one year of the project and devoted 50% to the action. Under a simple straight-line depreciation assumption, the attributable amount would be EUR 40,000 / 4 x 1 x 50% = EUR 5,000, subject to the beneficiary's accounting practices and the GA's eligibility conditions. This is an example, not an automatic reimbursement entitlement.
Keep the purchase documentation, asset register, depreciation method, dates and records supporting the project's share of use.
Primary source: AGA, Article 6.2.C.2: Equipment.
How are indirect costs calculated, and what mistakes should be avoided?
For standard Horizon Europe actual-cost grants, indirect costs are generally calculated at 25% of the eligible direct-cost base, excluding subcontracting, financial support to third parties and other excluded categories specified by the rules, including certain internally invoiced goods and services and cost categories already incorporating indirect costs. Do not apply 25% mechanically to every direct-cost line.
Illustrative calculation: A beneficiary reports EUR 100,000 in eligible personnel costs, EUR 20,000 in subcontracting and EUR 10,000 in eligible consumables. Assuming no other exclusions, the indirect-cost base is EUR 110,000 and the 25% flat rate produces EUR 27,500, not EUR 32,500.
The flat rate is intended to cover indirect costs; beneficiaries should not additionally declare the same overhead expenditure as direct costs. Check the particular GA and funding model before applying the standard calculation.
Primary sources: Regulation (EU) 2021/695, Article 35; AGA, Article 6.2.E.
What are the risks of double funding, currency conversion and costs near project boundaries?
The same cost cannot be declared twice for reimbursement from EU funding. Beneficiaries should also check how other funding sources interact with their cost claims and retain clear allocation records. Receiving funding from more than one source is not, by itself, proof that the same cost was claimed twice.
Example: A staff member works on two funded actions. The beneficiary must distinguish the effort and expenditure attributable to each rather than charge the same days to both.
For financial statements, beneficiaries whose accounts are not in euros must apply the conversion method prescribed by the GA and Portal guidance; an internally convenient exchange rate may not be acceptable. Costs incurred outside the action period require particular scrutiny, although the GA provides specific exceptions, including certain final-reporting costs. The payment date alone does not establish when a cost was incurred.
Primary source: AGA, Articles 6 and 21.
Does moving money between budget categories require an amendment?
Not necessarily. Horizon Europe generally allows certain budget transfers without an amendment where they do not entail a substantive change to the action or breach other GA conditions. However, changes affecting Annex 1, subcontracting arrangements, beneficiaries or other contractual elements may require a formal amendment or the granting authority's assessment.
Example: A partner needs additional consumables but less travel than anticipated. The financial transfer may be possible within the GA's flexibility; if the change also alters the scientific work or introduces a new outsourced action task, further checks are necessary.
Discuss material changes with the coordinator and consult the Project Officer through the appropriate channel before relying on a presumed authorisation.
Primary source: AGA, Article 5.5 and Article 39: Budget flexibility and amendments.
How should a beneficiary respond to a financial audit finding?
Respond with a precise explanation of the transaction, the applicable GA provision, and the documents supporting the declared cost. If a document is missing, identify any reliable alternative evidence rather than treating every missing form as automatic rejection or inventing records after the fact.
A useful response package contains the questioned amount and category, a short chronology, accounting and contractual references, relevant personnel or procurement evidence, and a reconciliation showing how the declared amount was calculated. If the finding is justified, document the correction and assess whether the same issue affects other claims.
For the broader audit process, read Mastering Horizon Europe Audits: A Complete Integrated Guide for Beneficiaries and Coordinators.
Primary source: AGA, Article 25: Checks, reviews, audits and investigations.
What financial controls should you put in place from the first month?
The most useful control is a recurring reconciliation between the project's technical activities, personnel records, procurement decisions, accounting entries and financial declarations. The following is a recommended internal control routine, not a mandatory Commission checklist.
- Before hiring or purchasing: confirm task relevance, cost category and applicable eligibility conditions. Evidence to retain: work plan reference, contract or purchase justification.
- Monthly: reconcile personnel effort, payroll and project activities. Evidence to retain: reliable time records, payroll and activity evidence.
- At each purchase: check procurement and conflicts of interest. Evidence to retain: selection rationale, contract, invoice and proof of delivery.
- Quarterly: compare spending with work completed and forecast remaining resources. Evidence to retain: budget dashboard and corrective-action log.
- Before reporting: reconcile financial statements with accounting records and supporting documents. Evidence to retain: category-level reconciliation and internal approvals.
- Before project closure: review outstanding commitments, reporting obligations and record retention. Evidence to retain: final evidence register and assigned document owners.
For a broader project-level workflow, see How Do You Manage a Horizon Europe Project from Grant Signature to Final Review?.
Conclusion: How can you reduce the risk of ineligible costs?
Reduce financial risk by checking the GA before committing expenditure, choosing the correct cost category, recording project effort reliably, documenting purchasing decisions and reconciling financial claims with actual project activities. No checklist can guarantee that an audit will accept every claim, but consistent records make eligibility easier to demonstrate and discrepancies easier to correct.
The key distinction is between doing useful project work and declaring an eligible, adequately evidenced cost. Both matter in an actual-cost Horizon Europe grant.
About the author
Julien Sudre works on Horizon Europe proposal development, collaborative project management and project communication. Through Grant 360, he develops practical resources to help research and innovation organisations prepare and implement EU-funded projects. This article provides general guidance; the signed Grant Agreement and applicable official rules govern each individual grant.