How Nostos scores a city
Dataset 2026.09.4, published 2026-09-26.
Every city gets nine factor scores from 0 to 100. The ranker combines them with your weights; city and compare pages use equal ("balanced") weights. Nothing is hand-tuned per city: the same formulas run over the same open dataset for every city.
Why "Nostos"
*Nostos* (νόστος) is the ancient Greek word for homecoming: the journey back to the place where you belong, the root of "nostalgia". For a nomad that place is not fixed, so this tool turns the question around. Instead of ranking cities by someone else's idea of "best", it asks what matters to you and scores every city against that, so the top of your list is the home that fits you.
Normalization
- Min–max:
(value − min) / (max − min) × 100, clamped to 0–100, where min and max are the dataset's own extremes. - Log min–max: the same on
ln(value), for right-skewed metrics (cost, speed, airport destinations) so a few very large values do not flatten everyone else. - Inverted where lower is better (cost, homicide rate, PM2.5).
- Fixed scale for air quality: 5 µg/m³ (the WHO guideline) scores 100 and 50 µg/m³ or worse scores 0, so one extreme city cannot distort the rest.
- Sub-metrics inside a factor are blended with the weights below. If a sub-metric is missing, the others are re-weighted. If every sub-metric is missing, the factor is null and the page shows a "missing data" badge.
The nine factors
| Factor | Formula | Level |
|---|---|---|
| Cost of living | inverted log min–max of monthly cost for one person (rent included) | city for most cities, else country estimate |
| Safety | 50% political stability (WGI, min–max) + 50% inverted log1p min–max of homicide rate | country |
| Healthcare | 60% WHO UHC service-coverage index + 40% min–max life expectancy | country |
| Internet | 80% log min–max median download + 20% log min–max median upload (M-Lab measured) | city |
| Visa ease | Entry ease for your passport (0–65): home country or 180+ visa-free days 65, 90 days 46, 30 days 33, eTA 42, visa on arrival 34, e-visa 32, consular visa 6, not admitted 0. Plus a long-stay path (0–35): a nomad visa gives 15 + 20 × affordability (inverted min–max of its income threshold; 25 in total if unknown); without one, 180+ visa-free days give 25. A passport that is not admitted scores 0 regardless, and its own country scores 100. Until a passport is chosen in the ranker, the average of the US, German and British visa-free day counts stands in for the entry rule. | country |
| Getting there & around | 60% log min–max of non-stop airport destinations + 20% walkability + 20% transit (editorial 1–5) | city / editorial |
| Climate | share of months that are comfortable: mean 15–28 °C, at most 150 mm precipitation, at most 85% relative humidity (NASA POWER 2001–2020 normals) | city |
| Air quality | inverted fixed scale of annual mean PM2.5 (5 → 100, 50 → 0) | city |
| Quality of life | 70% min–max Human Development Index + 30% English band (native 100, very high 95, high 80, moderate 60, low 35, very low 15) | country |
Units
Prices are shown in US dollars. Temperatures default to Fahrenheit and rain to inches, with a toggle for °C and mm. The visa factor uses a US passport until you choose your own in the ranker, where every passport is scored the same way. The dataset itself stores Celsius and millimetres.
Composite score
score = Σ (weight × factor) / Σ weight over factors that have data and a weight above 0. Coverage is the share of your total weight that had data behind it. Cities with coverage under 50% are shown muted and sorted after fully covered ones. Ties break on coverage, then name.
Presets
- Balanced: every factor 5.
- Budget first: cost 10, visa 6, internet 6, safety 5, climate 4, others 3.
- Safety first: safety 10, healthcare 8, air 6, quality of life 6, cost 4, internet 4, others 3.
- Fast internet: internet 10, mobility 6, cost 5, visa 5, others 4.
Similar cities
Root-mean-square distance across the factor scores both cities have, requiring at least six shared factors. Each city page lists its five nearest, and those pairs are the prebuilt comparison pages.
What the data can and cannot say
- Country-level metrics (safety, healthcare, HDI, English) apply to every city in a country, so Lisbon and Porto tie on them. They are labeled on every page.
- Cost is a single-person monthly figure including rent, taken in this priority: (1) WhereToEmigrate city rows; (2) for US cities, the national estimate scaled by the metro's Bureau of Economic Analysis Regional Price Parity (2024), so Honolulu and New Orleans differ; (3) WhereNext's per-city estimate, multiplied by 1.12, the median ratio between the two sources on the 45 cities both cover, so the baskets are comparable; (4) WhereNext's country estimate, labeled country-level. Every city page names the source used.
- Internet is measured by users running M-Lab tests, which run below advertised plan speeds everywhere. Compare cities; do not read the number as your future plan speed.
- Air quality is the latest annual PM2.5 from the WHO Ambient Air Quality Database where a monitor exists (247 cities), a cited local source for a handful more, and otherwise the Washington University SatPM2.5 satellite estimate for the city-centre grid cell (2023), scaled to same-country WHO monitors where there are any. Satellite values track the WHO measurements closely (log-correlation 0.88, median difference 2 µg/m³) but can run high over desert dust.
- Monthly cost for most cities is a single-person budget that assumes a one-bedroom outside the centre; city pages also show the centre and outskirts rents and the budget with a central one-bedroom.
- Visa-free stays with no stated length count as unlimited only inside free-movement areas (EU/EEA and Switzerland, UK–Ireland, ECOWAS, the Gulf states, Australia–New Zealand, the East African Community, India–Nepal–Bhutan, the US Compact states); elsewhere the destination's typical stay is used (90 days, or 30 for the Dominican Republic) and labelled as approximate.
- Airport destinations are counted from the "Airlines and destinations" table on each airport's Wikipedia article (seasonal routes included, charters and not-yet-started routes excluded), with destination countries resolved through Wikidata; the OpenFlights 2014 snapshot is the fallback where an airport has no article. Treat them as hub size, not current schedules.
- Visa rules come from the Passport Index dataset (compiled from passportindex.org) and change often; verify with the issuing government. Walkability and transit are curated by Navoy, not measured, and are marked editorial.
- Climate comfort thresholds are a judgment call, documented above, applied identically everywhere.
- Taiwan is absent from WHO, World Bank and UNDP data; Taipei uses official Taiwan statistics, cited on its page.
Sources, licenses and the downloadable dataset are on the data page.