Person-months on research grants: how to calculate them
What a person-month is, how to work one out, and where funders use them and where they don't, from the Commission's and UKRI's own documents. Written for research offices planning and reporting staff time.
Checked against the AGA v2.0, the Horizon Europe application form V5.1, the MSCA Financial Guide V2.0, the ERC Work Programme 2026 and UKRI's costs guidance · October 2026
The short answer
A person-month is one person's full working time for one month, so someone on 50% for 12 months is 6 person-months. Horizon Europe proposals plan staff effort in person-months per work package, and Marie Skłodowska-Curie unit costs are paid per person-month.
But Horizon Europe declares actual personnel costs in day-equivalents, not person-months, and the Commission publishes no conversion between the two. UKRI doesn't use person-months at all: it counts staff time in hours and caps it at 100% FTE.
Working out person-months
Multiply the share of the person's working time by the number of months:
| Who | Share of time | Months | Person-months |
|---|---|---|---|
| A full-time postdoc on one grant | 100% | 12 | 12 |
| A postdoc split across two grants | 50% | 12 | 6 on each |
| A technician for part of a project | 20% | 36 | 7.2 |
| A part-time researcher on 0.6 FTE, all on the project | 60% | 6 | 3.6 |
| One month split 60/40 across two grants | 60% and 40% | 1 | 0.6 and 0.4 |
This is arithmetic, not a funder's rule. The Commission's MSCA guide gives the same logic for part-time work: "For one month of 50% part-time employment, 0.5 units should be claimed". Across all of a person's grants, the shares in any month can't add up to more than 100%.
Horizon Europe: planned in person-months, declared in days
The application form asks for person-months in two places: the resources in each work package description, and Table 3.1f, the summary of staff effort, which asks for "the number of person/months over the whole duration of the planned work, for each work package, for each participant". The periodic report then asks you to explain deviations between actual and planned use of resources in Annex 1, "especially related to person-months per work package".
Actual personnel costs are declared differently. The Annotated Grant Agreement (Article 6.2.A.1) costs each person as a daily rate, their annual personnel costs divided by 215, multiplied by the day-equivalents they worked on the action, rounded to the nearest half-day. The word person-month doesn't appear in it.
- The days you can declare are capped at (215 / 12) multiplied by the months the person is employed in the reporting period, multiplied by their working time factor. For someone on 50% for 6 months that is 54 day-equivalents
- Across all EU grants, a person's day-equivalents can't exceed 215 in a calendar year, or 215 times their working time factor if they are part-time
- If you record hours, you convert them into day-equivalents in one of three ways, such as a fixed 8 hours a day, and apply that choice consistently
So 215 / 12, about 17.9 days, is a ceiling on what you can declare in a month, not an official length of a person-month. To compare the plan with what happened, convert the declared day-equivalents back with your own method, and keep it the same every period. The report explains deviations against the person-months in Annex 1.
Marie Skłodowska-Curie Actions: paid per person-month
MSCA grants are unit costs: the number of eligible units times the amount per unit, where the units are "months spent by the researchers on research training activities", so-called person-months or researcher-months. You report them in the mobility declaration.
- Part-time counts pro rata: one month at 50% is 0.5 person-months
- Part months count by the day, at 1/30 of a month each: 20 months and 15 days is 20.5 person-months
ERC: the principal investigator's time as a percentage
The ERC sets the principal investigator's commitment as a minimum share of their working time on the project, not in person-months. Applications below the minimums are declared ineligible.
| Grant | Minimum time on the project | Minimum time in the EU or an Associated Country |
|---|---|---|
| Starting | 50% | 50% |
| Consolidator | 40% | 50% |
| Advanced | 30% | 50% |
| Synergy | 30% for each principal investigator | 50% for each one hosted in the EU or an Associated Country |
UKRI: hours, not person-months
UKRI counts staff time in hours. Staff can charge "up to 100% of their contracted time", calculated "as a maximum of 37.5 hours a week, 44 weeks a year", and an individual's salary costs across grants must not exceed 100% FTE. EPSRC puts the most time the research councils will fund for any one investigator, across all their projects, at 1,650 hours a year, which is the same 37.5 hours over 44 weeks.
UKRI's grant terms don't use person-months, and its timesheets are monthly totals of all hours worked. If you plan in person-months, a full person-month on that basis is 1,650 / 12, or 137.5 hours: our arithmetic, not a UKRI figure.
Mistakes to avoid
- Treating 215 / 12 as the official length of a Horizon Europe person-month. It is the cap on the days you can declare
- Reporting the planned person-months as the time worked. Horizon Europe wants the days actually worked, and UKRI actual hours, not the budgeted split
- Letting one person's allocations add up to more than 100% in a month, or more than 215 day-equivalents a year across EU grants
- Changing your conversion method between reporting periods, which makes the comparison with Annex 1 meaningless
How UniTimesheet fits
UniTimesheet starts from person-months and ends with the hours actually worked:
- Allocations import from a CSV of person-months per person per month (1 PM is 100% of that month), including an allocation export from AllocBoard, our sister product for planning grant staffing
- Allocations that would take a person over 100% on any day are refused, so an over-allocated plan is caught before it reaches a timesheet
- Each month's timesheet is drafted in hours from those allocations and days off, and staff correct it to what they actually worked before they submit
What it doesn't do: it records hours by week and doesn't convert them into Horizon Europe day-equivalents, calculate personnel costs or count MSCA units. Your office does that from the approved timesheets, with the conversion method you have chosen.
Sources
This page summarises the funders' published documents. It is not legal or audit advice: your grant agreement and your research office have the final word.
- European Commission, EU Grants AGA: Annotated Grant Agreement, v2.0, 1 April 2025 (Article 20)
- European Commission, Application form (HE RIA and IA), V5.1, 22 January 2026 (Part B, section 3.1 and Table 3.1f)
- European Commission, Periodic report template (Horizon Europe and Euratom), V1.1, 1 May 2023 (section 5.2)
- European Commission, Horizon Europe MSCA Financial Guide, V2.0, 1 September 2026 (section 5, pp. 27 to 34)
- ERC Work Programme 2026 (section 1.4.2.3, pp. 19 to 20)
- UKRI, Find out what costs are eligible for UKRI funding, updated 13 May 2026
- EPSRC, Directly allocated costs, updated 7 May 2026
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