Sources and model provenance
Spain contribution and Barcelona reference check: 20 October 2026. UK reference check: 5 October 2026. Model 2026-10-20.1. Checking a source today does not make its underlying observations current.
What is verified, and what is modeled?
UK employee income-tax and National Insurance parameters were checked against HMRC guidance for 2026/27. Spain employee contribution parameters were checked against the 2026 BOE rules; Spanish IRPF remains a simplified illustration. City rents, living costs, city medians and income-percentile thresholds remain model assumptions. Their original row-level source mapping and observation dates are not recorded in the current dataset. We do not describe them as official statistics or independently validated benchmarks.
Source register
| Reference | Period and coverage | How we use it |
|---|---|---|
| BOE: 2026 social-security contribution rules | Effective 1 January 2026; checked 20 October 2026 Spain Ordinary indefinite employees, evenly distributed remuneration | Implemented annual approximation: employee rate 6.50%, cap €61,214.40, plus employee solidarity bands at 0.19%, 0.21% and 0.24%. FOGASA is employer-only. Excludes category minimum bases, overtime, irregular pay and special schemes. This does not validate the IRPF model. |
| TMB T-usual fares | 2026 tariff, checked 20 October 2026 Barcelona integrated transport area One person, one-zone T-usual, 30 consecutive days | Verified reference: €22.80 with the current discount. The €55 transport model allowance is a broader scenario budget, not this pass price. Two adults need separate personal passes; extra zones and other travel cost more. This reference does not validate the household transport allowance. |
| Generalitat rental-statistics methodology | Methodology updated 13 July 2026; checked 20 October 2026 Catalonia municipalities and Barcelona districts Rental contracts with deposits registered at INCASOL | Validation gap: the official measure is mean contractual rent, not asking rent or a one-/three-bedroom outside-centre quote. It cannot directly verify the calculator’s bedroom/location assumptions. Those inputs remain unverified; use an actual rental quote in the custom rent field. |
| HMRC income tax rates and personal allowances | 6 April 2026 to 5 April 2027 England, Wales and Northern Ireland Simplified employment-income scenario; Scotland excluded | Implemented: income tax bands and allowance taper above £100,000. Assumes salary is adjusted net income; no pension relief, student loans or benefits. |
| HMRC employer rates and thresholds 2026 to 2027 | 6 April 2026 to 5 April 2027 UK Category A employees below State Pension age | Implemented: annualised employee NI at 8% between £12,570 and £50,270, then 2%. Actual payroll is calculated by pay period. |
| INE Annual Wage Structure Survey 2024 | 2024 earnings, released 2026 Spain and autonomous communities Employees covered by the survey, including different working patterns | Background comparison only. Does not establish our city rent inputs, city medians or modeled top-income thresholds. |
| AEAT application of personal and family minimums | 2025 tax year Spain, with autonomous-community differences IRPF taxpayers | Limitation reference. The current simplified Spain model does not reproduce regional scales, family relief or the complete official calculation. It is not a Catalonia payroll calculator. |
| ONS Annual Survey of Hours and Earnings 2025 | April 2025 reference period UK Employee jobs; full-time and part-time estimates must be distinguished | Background comparison only. Our London salary thresholds are model assumptions, not a direct extraction of this survey. |
Model input status
| Input | Status | Interpretation |
|---|---|---|
| London tax | HMRC parameters checked, 2026/27 | Employment income only. No pension relief, student loans, benefits, Scottish rates or period-specific payroll adjustments. |
| Spain tax | 2026 contribution parameters checked; IRPF remains simplified | Employee contributions include MEI and solidarity under an annualised indefinite-employment scenario. Regional IRPF scales, deductible employment expenses and personal/family minimum calculations are not implemented. Not suitable for matching a Catalonia payslip or self-employed tax return. |
| Barcelona transport | Official pass price checked separately | TMB one-zone T-usual: €22.80 per person for 30 consecutive days. The model’s €55 allowance is a broader household budget assumption, not an official pass price. |
| Barcelona rent | Official statistical definition checked; model inputs unverified | INCASOL reports registered-contract mean rents. These do not directly validate bedroom-specific outside-centre or asking-rent assumptions. Use an actual quote in the calculator’s rent override. |
| Other country tax models | Mixed reference years | Some parameters predate 2026. An annual page title does not mean every tax rule is current. |
| Rent, costs and city medians | Legacy CushyIndex model inputs | Exact original source rows and observation dates unavailable. Sensitivity analysis is more useful than apparent precision. |
| Income percentiles | Modeled distribution | Not a measured population percentile. Do not mix household income, taxpayer income and employee wages. |
| Exchange rates | Static scenario assumptions | For the research report, £1 = €1.17. This is not an observed rate for the publication date. |
Downloads and reproducibility
The five-city relocation report publishes every budget component, scenario and exchange-rate assumption in JSON and CSV. These are derived model outputs, not republished third-party datasets.
See the methodology and corrections and review policy.