Cost-of-Living Equivalency — Methodology

Primary source: Numbeo, a crowd-sourced cost-of-living database with user-submitted prices for housing, groceries, transportation, utilities, dining, and more. Each city record on our site links to its Numbeo city page as the original source URL.

Cross-checking: Our editorial team validates each city record against additional public sources, including local government statistics, rental listing aggregators (Idealista, Rightmove, Zillow), and expat community reports. We do not scrape Numbeo automatically — each record is hand-curated and manually verified.

FX rates: Currency conversion uses mid-market rates from Frankfurter (ECB) and ExchangeRate-API, cached for 6 hours via Cloudflare KV. The FX source and timestamp are visible on the tool page.

Data status: Every city record carries a dataStatus field ('seed' or 'verified') and a lastVerified date. 'Seed' means the data has been submitted but not yet independently verified. 'Verified' means an editor has cross-checked the figures against official or authoritative sources.

Cost-of-living data is inherently variable. Within a single city:

• A 1-bedroom apartment in central Lisbon might range from €900/month to €2,000/month depending on building age, amenities, and exact location.
• Grocery costs vary based on shopping habits (supermarket vs. specialty stores, organic vs. conventional, cooking at home vs. eating out).
• Public transport costs are relatively fixed, but usage patterns vary widely.

Presenting a single "average" number implies a false precision that real life does not support. By showing bands (min–max), we communicate the actual range of costs that people report and observe. This is more honest and more useful for planning.

Implication for equivalency calculations: When the tool computes an equivalent income, it uses the midpoint of each city's cost band as the reference point. The result is therefore itself an estimate with inherent uncertainty — not a precise figure.

The equivalency calculation follows these steps:

1. Convert to common currency: If the two cities use different currencies, the tool converts the origin city's costs to the destination city's currency using mid-market FX rates from the current rate cache.
2. Compute per-category ratio: For each cost category (housing, food, transport, etc.), the ratio is computed as: avg(destination_band) / avg(origin_band). A ratio of 0.7 means the category is ~30% cheaper in the destination; 1.4 means ~40% more expensive.
3. Apply ratio to income: The user's income is converted to the destination currency and then adjusted by the overall cost ratio (weighted average across all essential categories) to produce the equivalent income range.
4. Display with context: Each category shows its own ratio and band comparison so users can see which costs are similar, cheaper, or more expensive — not just the overall figure.

What's included: Housing (1BR central and room shared), groceries, public transport, internet, gym membership, and health insurance estimate. These are essential categories for a basic quality of life in any city.

What's NOT included: Personal discretionary spending (entertainment, travel, shopping), one-time relocation costs (deposits, flights, visas), healthcare beyond basic insurance estimates, or lifestyle-specific costs (premium housing, international school fees, etc.).