Person-Months in EU Projects: What They Mean and How to Calculate Them
A person-month is the metric EU-funded projects use to express the effort one staff member devotes to a project over one month of full-time work. If a researcher works full-time on your project for a whole month, that equals one person-month. If they work half-time, the same calendar month equals 0.5 person-months. You calculate a person's contribution by multiplying the proportion of their working time spent on the project by the number of months they are appointed to it.
According to the European Commission, human effort expressed in person-months measures the relationship between the work to be performed and the scale, type and number of activities and deliverables planned during implementation (European Commission, "What is 'human effort' (person-months) and how to calculate it?", 2019). In a Horizon Europe proposal, you assign person-months to each work package, and those figures must be consistent with each partner's estimated personnel costs.
Person-months matter well beyond the proposal stage. The work package table you build for evaluators becomes Annex 1 of your Grant Agreement, a legally binding document under the Horizon Europe Model Grant Agreement (MGA). An inflated or unrealistic effort estimate therefore creates problems at implementation rather than at rejection. This article explains the definition, the calculation methods, and the link to the daily-rate personnel cost rules you report against.
Note: this article covers standard actual-cost grants. Lump-sum Horizon Europe grants operate under different rules and do not require person-months or day-equivalents for reporting. If your project falls under the lump-sum modality, the effort-recording sections below do not apply to you.
What Is a Person-Month in EU Projects?
A person-month is a unit of effort equal to one person working full-time for one month on a project. It is a planning and measurement metric, not a payment: it expresses how much of a person's working time goes to project tasks, independent of their salary or country. In Horizon Europe proposals, person-months are the standard way to quantify and plan human effort across work packages and partners at proposal stage; once a project is under way, that effort is tracked and reported in day-equivalents.
The concept is deliberately proportional. If an engineer spends 100% of their time on your project for six months, that is 6 person-months. If a senior researcher spends 20% of their time over the full 36-month duration, that is 0.2 x 36 = 7.2 person-months. Because effort is separated from cost, the metric lets evaluators compare workload across a consortium of partners in different member states with very different salary levels.
Person-months appear in Part B (the technical content of the proposal), where all participants assign effort to each work package. That effort must match the personnel costs each organisation enters in Part A (the administrative and budget section), according to the European Commission's guidance on human effort. The electronic submission system does not automatically reconcile the various budget tables, so consistency across the whole proposal package is the applicant's responsibility.
In practice, person-months are the shorthand a whole consortium speaks during proposal preparation. When a coordinator asks a partner "how many PMs can you commit to WP3?", they are asking how much staff effort that partner will guarantee. That answer drives both the technical credibility of the plan and the personnel budget behind it.
How Do You Calculate Person-Months at the Proposal Stage?
To calculate person-months, multiply the proportion of a person's working time devoted to the project by the number of months of their appointment on it. The Commission's indicative method for converting working days into person-months uses a reference of 220 working days per year (an estimation aid for proposal planning), giving roughly 18.33 working days per month, so 24 full working days equal 24 / 18.33 = 1.31 person-months (European Commission, "What is 'human effort' (person-months) and how to calculate it?", 2019). This 220-day figure is drawn from legacy Commission guidance and is used as an indicative planning tool; the operative figure for actual personnel cost calculation at reporting is 215 days per year, as set out in the Horizon Europe Annotated Grant Agreement (HE AGA).
The two figures serve different purposes and must not be confused. For a side-by-side comparison, see the table below.
| Parameter | Proposal stage (planning) | Reporting stage (actual costs) |
|---|---|---|
| Days per year reference | 220 (indicative, per Commission human effort guidance) | 215 (legal ceiling per HE AGA, Article 6.2.A.1, p.49) |
| Purpose | Estimate effort in person-months for work packages | Calculate daily rate and maximum declarable day-equivalents |
| Unit used | Person-months | Day-equivalents |
| Formula | Working-time proportion × months of appointment | Actual personnel costs ÷ maximum declarable day-equivalents (HE AGA, Article 6.2.A.1, p.52) |
| Legal basis | Proposal template / Commission human effort guidance | HE MGA / Annotated Grant Agreement |
A worked example
Imagine a 24-month Horizon Europe project. To estimate effort per person, apply the proportional method:
- A postdoctoral researcher working 100% on the project for all 24 months: 1.0 x 24 = 24 person-months.
- A principal investigator working 15% of their time across the full 24 months: 0.15 x 24 = 3.6 person-months.
- A technician working full-time but only during a 9-month build phase: 1.0 x 9 = 9 person-months.
In a real consortium, a researcher will rarely work on just one work package. Suppose the postdoctoral researcher above contributes to both WP2 (methodology, 18 person-months) and WP4 (dissemination, 6 person-months). Their per-WP effort must sum to their total 24 person-months, and both figures must be reflected in the Part A personnel budget for their organisation.
You distribute each person's total effort across the work packages they contribute to, so the sum of a partner's per-WP person-months matches that partner's total committed effort. Assigning effort to work packages is mandatory for all participants in Part B, and it must line up with the direct personnel costs declared per organisation.
A practical difficulty worth naming: partners tend to estimate effort optimistically to look committed, then struggle to deliver those hours during implementation. Because the work package table becomes Annex 1, over-estimating person-months converts into a contractual obligation you may not be able to justify at reporting. Commit the effort your teams can genuinely record, not the effort that looks ambitious on paper.
How Do Person-Months Convert Into Personnel Costs?
Person-months become personnel costs when you multiply the estimated effort by each organisation's cost per person-month, which itself derives from that person's daily rate. Personnel costs are typically the largest single category in a Horizon Europe budget. According to a European Commission presentation on the Personnel Unit Cost method, personnel costs represent approximately two-thirds of project budgets in most proposals (European Commission, Personnel Unit Cost presentation, June 2024).
At proposal stage you estimate a cost per person-month for each staff profile, based on normal salary rates. The Commission is explicit here: estimated staff costs must correspond to normal salary rates, documented by salary grids or long-term contracts, and cannot significantly exceed the rates generally applicable in the relevant geographical area for the staff profiles in question (European Commission, "What is 'human effort' (person-months) and how to calculate it?", 2019). These are direct grant costs: salary, social security charges, taxes and other remuneration components required by national law or the employment contract. They do not include overheads, which Horizon Europe reimburses separately through the 25% indirect cost flat rate.
At reporting stage, the calculation shifts from estimates to actual costs. Under the Horizon Europe Model Grant Agreement, the operative formula for actual personnel costs for employees (category A.1) is the daily rate multiplied by the number of day-equivalents worked on the action, rounded to the nearest half-day (HE AGA, Article 6.2.A.1, p.49). The daily rate itself is calculated using the operational formula set out in Article 6.2.A.1 of the AGA (see the section below), not the simplified "annual costs divided by 215" shorthand that appears in the MGA legal text.
A note on other personnel categories: the daily-rate rules described here apply to employees (category A.1). Natural persons with direct contracts (A.2) and seconded persons (A.3) have different daily-rate calculation methods set out in Articles 6.2.A.2 and 6.2.A.3 of the AGA (p.61). If your consortium includes these personnel types, check the relevant AGA provisions before finalising your budget.
This is where many consortia feel the gap between theory and practice. As the head of the Commission's common legal support service for Horizon Europe acknowledged in a 2024 webinar, the personnel cost calculation has, over successive framework programmes, become "a matter for specialists, highly trained lawyers and financial experts to get it right" (EU Science & Innovation, "Personnel Unit Cost, New cost method in Horizon Europe" webinar, April 2024). Understanding the daily-rate logic below keeps your proposal estimates realistic.
How Does the Daily Rate and 215-Day Ceiling Work?
The daily rate is the core figure that turns actual salary into a reportable personnel cost. Under Horizon Europe, the daily rate equals actual personnel costs during the reporting period divided by the maximum declarable day-equivalents in that period (HE AGA, Article 6.2.A.1, p.52). This single figure is then multiplied by the day-equivalents the person worked on the action.
The operative method sits in Article 6.2.A.1 of the Annotated Grant Agreement (AGA): the maximum declarable day-equivalents are calculated as (215 / 12) multiplied by the number of months the person is employed within the reporting period, multiplied by their working time factor (HE AGA, Article 6.2.A.1, p.52). This is the authoritative calculation method for Horizon Europe actual-cost claims. The MGA legal text in Article 6.2.A.1 (p.49) contains a simplified shorthand ("annual personnel costs divided by 215"), which is the legal-text boilerplate retained for regulatory reference.
The number 215 is the per-calendar-year horizontal ceiling on day-equivalents a person can declare across all EU grants. This ceiling applies universally to all beneficiaries for the purpose of calculating the daily rate and maximum declarable day-equivalents, irrespective of whether a person works on one grant or several. Where a person works across multiple EU actions in the same year, the ceiling additionally prevents double-funding by ensuring the total declared across all grants does not exceed 215 day-equivalents (HE AGA, Article 6.2.A.1, p.53). It is a cap, not a flat annual divisor. For a full-time employee, a six-month reporting period gives a maximum of (215 / 12) x 6 x 1 = 107.5 declarable day-equivalents (HE AGA, Article 6.2.A.1, p.53).
The working time factor scales the ceiling to part-time staff. Consider the AGA's own examples for a reporting period running from 1 January to 30 June 2022 (HE AGA, Article 6.2.A.1, p.53):
| Situation | Calculation | Max declarable day-equivalents |
|---|---|---|
| Full-time, hired before period | (215 / 12) x 6 x 1 | 107.5 |
| 50% part-time, hired before period | (215 / 12) x 6 x 0.5 | 54 |
| 50% part-time, hired 1 June 2022 | (215 / 12) x 1 x 0.5 | 9 |
If a person's actual day-equivalents worked on the action exceed the maximum declarable ceiling, only the ceiling figure may be used in the cost calculation. The excess days are simply not declarable, and you cannot carry them forward to another reporting period. This is why accurately forecasting part-time factors and employment start dates matters at proposal stage.
One further note on the daily rate. You can calculate it separately for each calendar year within the reporting period, provided you apply the approach consistently. In that case, the "number of months within the reporting period" in the formula refers to the months of the respective calendar year that fall within the reporting period (HE AGA, Article 6.2.A.1, p.52).
What Is the Personnel Unit Cost Option and Should You Use It?
The Personnel Unit Cost (PUC) method is a simplification tool available in Horizon Europe, authorised by a Decision of 15 January 2024. It replaces the full actual-cost calculation with a fixed daily rate approved in the Participant Register, making personnel cost reporting significantly less burdensome for eligible beneficiaries. If your organisation is eligible and your approved rate is already in the Participant Register, PUC can reduce audit risk substantially.
Under PUC, the formula is straightforward: the approved daily rate multiplied by the number of day-equivalents worked on the action (HE AGA, Article 6.2.A.6, p.71). The beneficiary records the days worked, and the IT system in the Funding and Tenders Portal handles the cost calculation automatically from the pre-approved rate. That removes the need to gather annual salary data, compute maximum declarable day-equivalents, and reconcile actual costs at each reporting period.
Eligibility for PUC requires that the beneficiary has had their daily rate approved and entered in the Participant Register. The rate is based on the figure requested by the beneficiary and validated by the granting authority.
One important distinction from the standard actual-cost treatment: for beneficiaries using PUC, the horizontal 215-day ceiling applies not only where a person works across multiple EU grants, but also where the person worked in only one EU grant during a given calendar year (HE AGA, Article 6.2.A.6, p.71). Under the standard actual-cost method, the ceiling similarly applies universally to the daily-rate formula, but the double-funding safeguard dimension is most visible in multi-grant scenarios.
The head of the Commission's common legal support service for Horizon Europe described PUC at the April 2024 webinar as a direct response to the complexity that had built up around personnel cost rules over successive framework programmes (EU Science & Innovation, "Personnel Unit Cost, New cost method in Horizon Europe" webinar, April 2024). Check whether your approved rate is in the Participant Register before your next proposal.
How Should You Record Effort During Implementation?
You record effort either through monthly declarations of days worked on the action or through a reliable time-recording system based on hours. The Commission recommends monthly declarations of days as the simpler route, because it limits record-keeping burden and avoids converting hours into day-equivalents (HE AGA, Article 20, p.209). Reliable time records must be dated and signed at least monthly by the person and their supervisor.
Two rounding rules often trip up financial managers. In the monthly declaration itself, no rounding is allowed: if a person with a standard 8-hour working day spends 2 hours on the action in a month, they must record 0.25 day-equivalents, not a rounded figure (HE AGA, Article 20, p.209). Rounding to the nearest half-day applies only at the cost-calculation stage, when totalling day-equivalents across the reporting period and when converting total hours into day-equivalents.
If you record hours rather than days, you convert to day-equivalents by dividing total hours worked on the action by the number of hours in a day-equivalent, then rounding to the nearest half-day (HE AGA, Article 20, p.210; Article 6.2.A.1, p.49). There are three options for defining a day-equivalent under the AGA (HE AGA, Article 6.2.A.1, p.60):
- Option 1: a day-equivalent is a flat 8 hours.
- Option 2: average working hours as per contract or another binding document (e.g. collective labour agreement, national labour legislation). For a full-time employee contracted to work 37.5 hours per week over 5 days, a day-equivalent is 7.5 hours.
- Option 3: a value derived from the beneficiary's usual cost accounting practice for the standard number of annual productive hours of a full-time employee.
If you do not have a formal timesheet system, the Commission provides a time declaration template tailored to Horizon Europe actions that meets the minimum reporting requirements. Missing or unsigned time records were among the most frequently cited audit findings under Horizon 2020, according to the consultancy accelopment's analysis of Commission audit patterns (accelopment, "How to comply with EU financial rules in Horizon Europe projects", December 2023). The financial rules in this area remain largely unchanged in Horizon Europe, so the risk persists.
How Do You Manage Person-Months During Horizon Europe Implementation?
For coordinators, person-months are the bridge between the technical plan and the budget. Treat them as a joint responsibility of the scientific and financial teams. Get the effort distribution right at proposal stage and reporting becomes a reconciliation exercise. Get it wrong and you spend the project defending numbers you cannot record.
Here are specific, actionable steps:
- Build a person-months matrix before the kick-off meeting that maps each partner's committed effort to each work package, using the proportional method (working-time proportion x months). Cross-check that the sum of per-WP person-months for each partner equals their total effort and matches their Part A personnel budget.
- Convert person-months to a realistic cost using each partner's actual salary grids. Ask partners for their approved Participant Register daily rate if they use the Personnel Unit Cost (PUC) option, so your budget figures survive audit.
- Reserve a margin for coordination effort. Many coordinators underestimate the person-months needed for project management, consortium meetings, and reporting in the management work package (typically WP1), then find themselves under-resourced from Month 1.
- If a partner withdraws in, say, Month 18, reallocate their remaining person-months through a Grant Agreement amendment (governed by Article 39 of the MGA) and update Annex 1 rather than quietly absorbing the effort elsewhere. Undocumented effort shifts create reporting inconsistencies.
A concrete scenario: suppose WP4 was planned at 30 person-months split across three partners, and by the mid-term review one partner has recorded only 40% of its committed effort. The coordinator should raise this in the consortium meeting, document the reason, and either redistribute the remaining effort formally or adjust the deliverable scope. At final reporting, the recorded day-equivalents must justify the personnel costs claimed. For deeper budget mechanics, EMDESK Academy's guides on calculating Horizon Europe personnel costs and average person-month rates expand on the daily-rate figures.
How Do You Ensure Your Person-Month Estimates Hold Up at Audit?
Person-months are the shared language of effort in EU projects, connecting the technical ambition of your proposal to the personnel budget that funds it. The proposal-stage estimate uses an indicative 220-working-day reference to convert time into effort, while the reporting stage relies on the Article 6.2.A.1 daily-rate formula with its 215-day annual ceiling. Keep the two figures distinct in your planning.
Because the work package effort table becomes a binding part of your Grant Agreement, the discipline that pays off is honesty at estimation. Commit the person-months your teams can genuinely record and justify, keep reliable monthly time records from day one, and treat any change in effort as something to document through an amendment. You can find current calls and programme guidance on the EU Funding & Tenders Portal and the full rules in the Horizon Europe Annotated Grant Agreement.
Frequently Asked Questions
What is the difference between a person-month and a full-time equivalent (FTE)?
A person-month measures effort over a single month, while a full-time equivalent (FTE) measures effort over a year. One FTE working the full year equals roughly 12 person-months. A person-month is the standard planning unit in Horizon Europe proposals, where you assign effort per work package, whereas FTE is more common in annual reporting contexts.
Why does the proposal stage use 220 working days but reporting uses 215?
The 220-day figure is an indicative estimation aid for converting working days into person-months during proposal preparation, per the European Commission's human effort guidance (dated 2019). The 215-day figure is the legal horizontal ceiling on declarable day-equivalents per calendar year, used at reporting to calculate actual personnel costs (HE AGA, Article 6.2.A.1, p.49 and p.52). The two figures serve different purposes: one is a planning approximation, the other is a binding legal cap.
Why does the 2019 Commission guidance still apply under Horizon Europe?
The Commission's FAQ "What is 'human effort' (person-months) and how to calculate it?" (published 2019, originally for the Commission's Justice-programme calls) is still online and has not been superseded, so its 220-working-day reference remains the Commission's published planning convention. Nothing in a Horizon Europe proposal legally depends on it: effort is entered directly in person-months, and any reasonable estimation method is acceptable. Some national contact points, such as Austria's FFG, instead estimate person-months from an organisation's actual annual productive hours divided by 12. At reporting, the binding figure is the 215-day ceiling on declarable day-equivalents (HE AGA, Article 6.2.A.1).
How do I calculate person-months for a part-time employee?
Multiply the person's working-time proportion by the number of months they work on the project. A researcher working 50% part-time for 12 months on the action contributes 0.5 x 12 = 6 person-months. At reporting, their maximum declarable day-equivalents are scaled by the same working time factor: (215 / 12) x 12 x 0.5 = 107.5 per year (HE AGA, Article 6.2.A.1, p.53).
Do person-months include overhead or indirect costs?
No. Person-months quantify direct personnel effort only, and the personnel costs behind them cover salary, social security, taxes and other remuneration required by law or contract (HE AGA, Article 6.2.A.1, p.49). Indirect costs are reimbursed separately in Horizon Europe through the 25% indirect cost flat rate, which is added on top of eligible direct costs and is not part of the person-month calculation.
What happens if my recorded effort does not match the person-months in Annex 1?
The work package effort table becomes Annex 1 of your Grant Agreement, a binding document, so significant discrepancies must be justified at reporting or corrected through an amendment (MGA, Article 39). Personnel costs are only eligible if supported by identifiable, verifiable day-equivalents recorded in signed monthly declarations or a reliable time-recording system (HE AGA, Article 20, p.209). Unjustified effort risks cost rejection at audit.
Do lump-sum Horizon Europe grants require person-months or day-equivalents?
No. Lump-sum grants operate under a completely different reporting modality. Personnel costs are not reported through day-equivalents or daily rates; instead, payment is tied to the completion of work packages as defined in the Grant Agreement. If your project is funded under the lump-sum scheme, the effort-recording rules described in this article do not apply.
