The Real Cost-of-Living Comparison: A Practical Framework for Anyone Moving Abroad

Why the salary headline lies

When recruiters quote a salary for a job abroad, they almost always quote the gross. When you actually live in the new city, what matters is the net, after-housing, after-tax, after-transport discretionary residual. Two cities that look identical on the salary line can produce wildly different lives once you account for what each city quietly takes from your paycheck before you've spent a single dollar on yourself.

A useful number to internalise: across the cities on this site, the median rent share of net pay ranges from 22% (Lisbon, Berlin) to 48% (Zurich, Hong Kong, San Francisco). A 25-percentage-point swing in housing cost can vaporise the most generous relocation package.

The four-line cost-of-living audit

Before you compare two cities seriously, build the following four-line audit. You can do this in a notebook in fifteen minutes per city.

1. Net monthly income

Take the gross salary the employer is offering. Apply the country's effective tax rate at your bracket. (Use the OECD "Taxing Wages" report or any local tax calculator — the headline marginal rate is rarely what you'll actually pay because of social contributions and credits.) Subtract employee social security, pension and health-insurance contributions. The remainder is what hits your account.

2. Target rent

Decide on a lifestyle: 1-bed, 2-bed, central, suburban. Pull median rents from a local site such as Idealista (Spain/Portugal), Immobilienscout (Germany), Rightmove (UK), Hemnet (Sweden), 99co (Singapore), or Numbeo's "Rent Index" for a rough cross-check. Use the median, not the cheapest listing — the cheapest listing is invariably an outlier and not somewhere you would actually live.

3. Recurring fixed costs

Add up the things that hit your account every month regardless of how disciplined you are: utilities (€100–€250 typical), internet (€30–€60), public transport pass (€50–€150), groceries for one person (€250–€450), health insurance top-up if relevant, gym, phone. For most single adults in a developed-economy city, this block lands between €500 and €900 a month.

4. Discretionary residual

Net income minus rent minus fixed costs equals the discretionary residual. This is the number you should compare across cities, not the gross salary, not even the net salary. The discretionary residual is what funds your travel, your savings, your meals out, and your sanity.

A worked example: Munich vs Berlin

Suppose you have an offer for €85,000 gross in Munich and another for €72,000 gross in Berlin. Salary alone says Munich wins easily. Let's run the audit:

• Net income. Both Germany; the effective tax + social rate for a single childless earner at these levels is roughly 39%. Munich net ≈ €4,320/month. Berlin net ≈ €3,660/month. Munich is +€660/month ahead so far.
• Rent. A median modern 2-bed in central Munich runs €1,950. The same in central Berlin runs €1,500. Munich is now only +€210/month ahead.
• Fixed costs. Roughly identical in both cities; €700/month either way.
• Discretionary residual. Munich €1,670/month vs Berlin €1,460/month.

A €13,000 gross salary advantage compresses to a €210/month real-life advantage. If you'd take Berlin's livelier night life or shorter commute to your friends seriously, the "obvious" Munich offer is in fact a coin flip — exactly the kind of judgment the four-line audit is built to surface.

Why purchasing-power indices help, but only as a sanity check

The Numbeo-style "Local Purchasing Power" index that you'll see in our compare tool divides the average net salary by the average local cost of a representative basket. It is a useful triangulation tool but not a substitute for your own audit, because:

• Your basket is not the average basket. Your rent is not the average rent.
• Purchasing power averages mask massive intra-city dispersion: central Paris and the Paris suburbs are nearly different countries on cost.
• The "salary" component is an average across all jobs. Your offer is for a specific role.

Use purchasing-power indices to rule cities out, not to rule them in. If the index says Lagos has 30% of New York's purchasing power, you can trust that as a directional signal that Lagos is meaningfully harder for the median worker. Whether it is harder for you, on your salary, in your preferred neighbourhood, requires the four-line audit above.

What to do with currency exposure

If you earn in one currency and have liabilities (a mortgage, family support, student loans) in another, you're carrying an unintentional FX position. A 10% move in the cross — historically common across any 12-month window — can shift your real income by enough to overwhelm a routine raise.

Three pragmatic rules:

1. Match liabilities to the currency of your income. If you earn in euros and owe pounds, you are short euros and long pounds without having chosen to be.
2. Keep an emergency fund in your spending currency, not your home currency. Six months of expenses in the wrong currency is six months of FX risk you didn't sign up for.
3. Re-baseline annually. Run the four-line audit again at 12-month intervals, in your current spending currency, with current rents. Cities drift; budgets drift faster.

The relocation contract negotiation

Once you have the audit numbers, you have leverage in the relocation negotiation. Concrete asks that are very rarely refused if you can defend them with arithmetic:

• A cost-of-living differential allowance for the first 1–3 years if the destination city's discretionary residual is materially lower.
• An FX hedge or annual currency review clause if your liabilities sit in a different currency.
• A housing search budget (typically €2,000–€5,000) to cover relocation agency fees, which the four-line audit will have priced in but the offer letter usually has not.

FAQ

Is a 30% raise enough to justify moving to a more expensive city? Not by itself. Apply the four-line audit. A 30% raise that funds an 80% increase in rent typically lowers your discretionary residual. A 30% raise that funds a 20% increase in rent typically more than doubles it. Same headline number, opposite outcomes.

How do I estimate effective tax rates without an accountant? The OECD's "Taxing Wages" annual report publishes effective average tax rates for a single person at 100% of average earnings in every member country. It is the cleanest single source. For non-OECD destinations, consult the local Big Four tax firm's annual personal-tax guide — most are published free as PDFs.

Are Numbeo / Expatistan numbers reliable? Directionally yes, precisely no. They are crowdsourced from voluntary contributions and can lag by 6–18 months in fast-moving rental markets. Use them to compare cities to each other; do not treat them as a quote for your own lifestyle.

Should I factor childcare and schooling in if I have children? Absolutely. In several European countries, public childcare is heavily subsidised; in the US, the UK and Singapore, it is one of the largest line items in a young family's budget. Childcare is often a six-figure annual swing item between cities. It belongs in "recurring fixed costs" in the audit if relevant to you.

How often should I re-run the audit? Annually, and any time you receive a counter-offer or a promotion. Cities change. Your numbers change. The audit takes 15 minutes per city; re-running it is the highest-leverage 30 minutes of personal-finance work you can do as a globally mobile professional.