How we got each number

Figures checked 24 September 2026

This page shows the working behind every economic, visitor and jobs figure on our € economy map and our book-home economic hypothesis. For each number you get: what it is, where it appears, what kind of number it is, where it comes from, and the arithmetic. Anyone can check it.

We use four labels:

PUBLISHED: a figure printed by an official body, an audited account or a named report. We quote it as printed.
ESTIMATE: our own calculation from published inputs. We show the working.
HYPOTHESIS: campaign modelling of what a permanent Book of Kells home in Kells could mean. It is built from published Irish analogues and official multipliers, and it is always labelled.
FIXED FACT: a geographic or historical fact that doesn't change year to year.

Checkable figures

1. Trinity / Dublin: published figures

€20.24m: Trinity Library income, FY2023

Where it appears: Map: the headline, the "Status quo · Dublin (published)" card, the slider caption, "How to read the money", and the Trinity pin (shown there as €20.238m / €20.2m). Hypothesis page: "The problem".
Type: PUBLISHED
Source: Trinity College Dublin, Consolidated Financial Statements 2022/23, Library income €20,238,000 for the year to 30 September 2023 (PDF). RTÉ (5 June 2024) reports that this line is Book of Kells exhibition income, including the Old Library Shop and guided tours (RTÉ).
Calculation: €20,238,000 rounded to €20.24m (and to €20.2m on the pin title).
Range: Published figure, no range. For context, the same line was €18.33m in FY2019 (TCD FS 2018/19).

968,666: Book of Kells visitors, 2024

Where it appears: Map: the headline, the status-quo card, the slider caption, "How to read the money", and the "Trinity visitor volumes" pin. Hypothesis page: "The problem".
Type: PUBLISHED
Source: Fáilte Ireland, Visitor Attractions dashboard, Book of Kells, calendar year 2024 (Fáilte Ireland).
Calculation: None. Quoted as published.
Range: Published figure, no range. Year to year: 968,654 (2023, Fáilte) and 1,057,642 (2018, Fáilte). Trinity's own figure via RTÉ was about 900,000 for FY2023. That covers a financial year, not a calendar year, so we keep the two separate.

€25.138m and €27.961m: Trinity "Visitor Income", FY2024 and FY2025

Where it appears: Map: the Trinity Library income pin.
Type: PUBLISHED
Source: TCD Consolidated Financial Statements 2023/24 (PDF) and 2024/25 (PDF). Consolidated Visitor Income was €25,138,000 (FY2024) and €27,961,000 (FY2025).
Note: From FY2024 Trinity renamed the line "Visitor Income", and it now includes new visitor streams. It is wider than the Book of Kells alone, which is why we say so on the map. We use €20.24m (FY2023) as the headline Book of Kells figure.
Range: Published figures, no range.

€5.2m and €1.2m: Old Library Shop revenue, 2019 and 2020

Where it appears: Map: the "Old Library Shop — historical" pin.
Type: PUBLISHED
Source: €5.2m for the year to September 2019, from RTÉ, 17 April 2020 (RTÉ). €1.2m for the year to September 2020, from the Irish Examiner, 16 April 2021 (Irish Examiner).
Note: 2020 was the Covid-closure year. These are the last years in which the shop was reported separately. Later accounts include it in Library / Visitor Income.
Range: Published figures, no range.

2. Kells / Meath context

Kells revenue line. No published figure for Kells tourism revenue is comparable to Trinity's Library income, so the map doesn't show one. The Kells heritage pins (Round Tower, High Crosses, St Colmcille's House, the Courthouse hub, the St Columba's Church site) are real places shown for context, and they carry no € or visitor figures.
Trinity College Dublin to Kells: 69 km by road. FIXED FACT.
Meath's leading heritage magnet: Brú na Bóinne had 133,991 visitors in 2024 (OPW). It is used below as the floor for our conservative scenario.

3. Book-home hypothesis: scenarios, spend, jobs, bednights

All figures in this section are HYPOTHESIS: campaign modelling for a permanent, purpose-built Book of Kells destination in Kells. The map and the hypothesis page show the mid scenario.

Three visitor scenarios

Scenario	Annual visitors	Anchored to (published)
Conservative	150,000	Brú na Bóinne, 133,991 (2024, OPW)
Mid	350,000	Rock of Cashel, 357,273 (2023) and 365,505 (2024)
Ambitious	550,000	Kylemore Abbey, 573,000 (2024, Fitzpatrick Associates)

Even the ambitious case is well below the 968,666 people who saw the Book in Dublin in 2024.

350,000 annual visitors (mid)

Where it appears: Map: the headline, the book-home card "350k", the slider caption, "How to read the money", and the Kells pins. Hypothesis page: the numbers table.
Type: HYPOTHESIS
Source figure: Rock of Cashel, 365,505 visitors in 2024 (OPW) and 357,273 in 2023 (Tipperary Tourism Roadmap 2025–2030). Cashel is a religious monument above a small inland town.
Assumption: A permanent home for the Book in Kells draws at least Cashel-scale demand. The Book is a stronger global brand than the Rock.
Calculation: Set just below Cashel's 2023–2024 range (357,273–365,505), then rounded to 350,000.
Range: Low 150,000 / Mid 350,000 / High 550,000.

~€9m a year: on-site ticket and retail

Where it appears: Map: the book-home card "~€9m", the slider caption, and "How to read the money". Hypothesis page: the numbers table.
Type: HYPOTHESIS
Source figures: Irish ticket prices. Rock of Cashel adult €8 (Irish Examiner, 2022); Newgrange adult tour €18 (Irish Examiner, 2022); Book of Kells Experience from €26 (visittrinity.ie, September 2026). Retail ratio from Trinity 2019: the Old Library Shop took €5.2m against €12.7m in Book of Kells visitor income (RTÉ, 17 April 2020).
Assumption: Blended ticket yield of €15–€25 per visitor (mid €20), which sits between the OPW heritage prices and Dublin's Book of Kells Experience price. Retail and secondary spend is added at 25–30% of ticket revenue. That is deliberately below Trinity's own 2019 ratio, when shop revenue equalled about 41% of visitor income (€5.2m ÷ €12.7m).
Calculation (mid): 350,000 × €20 = €7.0m ticket. Plus about €2.0m retail (≈28% of ticket). Total ≈ €9.0m.
Range: Low €6.6m (350,000 × €15 = €5.25m, plus 25% = €1.3m) / Mid €9.0m / High €11.4m (350,000 × €25 = €8.75m, plus 30% = €2.6m).
This is operator revenue for a Kells destination. It is not Trinity's €20.24m moved across.

~€35m a year: wider local / Boyne Valley spend (excluding tickets)

Where it appears: Map: the book-home card "~€35m", the slider caption, "How to read the money", and the coach and local-retention pins. Hypothesis page: the numbers table.
Type: HYPOTHESIS
Source figure: Kylemore Abbey, €78.2m in regional tourist spend attributed to 573,000 visitors in 2024 (Fitzpatrick Associates, Kylemore Abbey – Economic Impact Update, August 2025, PDF). That works out at €78.2m ÷ 573,000 ≈ €136 per visitor.
Assumption: Each visitor spends €100 in Kells, Meath and the Boyne Valley on food, beds, transport and shopping, excluding the ticket. That is below Kylemore's €136.
Calculation (mid): 350,000 × €100 = €35.0m.
Range: Low €24.5m (€70 per visitor) / Mid €35.0m (€100) / High €47.6m (€136, the Kylemore average).

~€44m a year: combined regional economic activity

Where it appears: Map: the headline, the book-home card "~€44m", the slider caption, "How to read the money", and the Kells pins. Hypothesis page: the numbers table.
Type: HYPOTHESIS
Calculation (mid): €9.0m on-site + €35.0m local spend = €44.0m.
Range: Low €31.1m / Mid €44.0m / High €59.0m.

~970 jobs supported

Where it appears: Map: the headline, the book-home card "~970" (labelled "tourism jobs"), the slider caption, "How to read the money", and the Kells pins. Hypothesis page: the numbers table ("Tourism jobs supported (@ €1m → 22 jobs)").
Type: HYPOTHESIS
Source figure: Fáilte Ireland's employment factor: every €1m of tourist spend supports about 22 jobs (see Multipliers below).
Calculation (mid): €44.0m × 22 = 968, rounded to ~970.
Range: Low ~680 (€31.1m × 22) / Mid ~970 / High ~1,300 (€59.0m × 22).
These are jobs supported across the regional economy by visitor spend, not staff at the site itself. Our analogue band for direct site staff is 80–120 FTE in the mid case.

~308,000 bednights a year (supporting figure)

Where it appears: This method page only. It is not shown on the map or the hypothesis page.
Type: HYPOTHESIS
Assumption: 40% of visitors stay overnight in Meath or the Boyne Valley. That is between the Durham 2013 exhibition sample (26%) and Kylemore's overnight visitors (about 88%). The average stay is 2.2 nights, in line with regional domestic stays (Tipperary 2.0, Kilkenny 2.3, Hidden Heartlands 2.2).
Calculation (mid): 350,000 × 0.40 × 2.2 = 308,000.
Range: Low ~250,000 (30% × 2.0 nights) / Mid ~308,000 / High ~420,000 (50% × 2.4 nights).

Scenario scoreboard (all HYPOTHESIS, mid yields)

	Conservative 150k	Mid 350k	Ambitious 550k
On-site ticket + retail	~€3.9m	~€9.0m	~€14.1m
Local spend @ €100/visitor	€15.0m	€35.0m	€55.0m
Combined	~€19m	~€44m	~€69m
Jobs @ 22 per €1m	~420	~970	~1,520
Bednights (40% × 2.2)	~132,000	~308,000	~484,000

4. Analogue sites (published)

Rock of Cashel: 357,273 (2023) and 365,505 (2024)

Where it appears: Hypothesis page: "Why those numbers are plausible".
Type: PUBLISHED
Source: 2024: Office of Public Works, 2024 visitor data for heritage sites (gov.ie). 2023: Tipperary Tourism Roadmap 2025–2030 (PDF).
Range: Published figures, no range. Year-to-year change +2.3%.

Kylemore Abbey: 573,000 visitors, €78.2m regional spend (2024)

Where it appears: Hypothesis page (named as the method model and the ceiling analogue). Basis of the €35m, ~970 and ambitious-scenario figures.
Type: PUBLISHED
Source: Fitzpatrick Associates, Kylemore Abbey – Economic Impact Update, August 2025 (PDF). The report gives 573,000 total visitors (344,000 fee-paying), €78.2m in attributed regional tourist spend, 1,720 jobs from tourist spend at €1m → 22, and more than 115 direct jobs (about 93 FTE).
Range: Published figures, no range.

Brú na Bóinne: 133,991 visitors (2024)

Where it appears: Hypothesis page (named as the Meath floor). Basis of the conservative scenario.
Type: PUBLISHED
Source: OPW 2024 visitor data (as above). For 2023 (114,934): Meath Chronicle, 29 March 2024.
Range: Published figures, no range. Year to year: 114,934 → 133,991.

Lindisfarne Gospels, Durham 2013: £8.3m in three months

Where it appears: Hypothesis page: "Why those numbers are plausible".
Type: PUBLISHED
Source: BBC News, "Lindisfarne Gospels bring £8.3m to Durham economy" (BBC), reporting Visit County Durham's impact report. About 100,000 visitors came to the July–September 2013 exhibition and the festival around it.
Note: The figure is in pounds sterling and is not converted into our euro tables. It is a precedent for a manuscript going back to its home region, not an input to the Kells arithmetic.
Range: Published figure, no range.

5. Multipliers used

€1m of tourist spend supports about 22 jobs

Where it appears: Hypothesis page: the numbers table and "Why those numbers are plausible". Basis of ~970 jobs.
Type: PUBLISHED (official multiplier)
Source: Fáilte Ireland, Key Tourism Facts 2023, as cited in the Kylemore Abbey Economic Impact Update (Fitzpatrick Associates, 2025, PDF) and in the Limerick Tourism Plan 2025–2030.
Note: Older Fáilte editions used €1m → 27 jobs. We use the current, lower figure of 22.

Other working assumptions (all shown above)

Ticket yield: €15 / €20 / €25 per visitor
Retail: 25–30% of ticket revenue
Local spend: €70 / €100 / €136 per visitor
Overnight share: 40% (30–50% band). Average stay: 2.2 nights (2.0–2.4 band)

What these numbers are not

The published figures are exactly what Trinity, Fáilte Ireland, the OPW and the named reports printed. The book-home figures are a hypothesis. They are not a forecast, not a business plan, and not audited accounts, and they are not Trinity's figures. They answer one question in the open, with every input shown: if the Book of Kells came home to Kells as a permanent, properly built destination, what scale of economy would Irish evidence point to? The answer is hundreds of thousands of visitors, tens of millions of euro, and hundreds of jobs. If you want to test it, change any input above and run the arithmetic yourself.