Where the numbers come from

The wage-tax formula

The Federal Finance Ministry's Programmablaufplan, translated into the calculation of income tax, the solidarity surcharge and the church-tax base.

Agreement with the tax office's calculator

A fixed set of test cases is sent to the Federal Finance Ministry's own online calculator and every result is compared with ours. This is run by hand whenever the formula changes, and once a year when the new formula is published.

Contribution rates and ceilings

What each branch of social insurance charges, and the earnings above which it stops charging.

Health fund rates

The Zusatzbeitrag each statutory fund sets for itself, which is the largest thing a reader can change about their own net pay.

Pension values

What one Entgeltpunkt pays and what the national average wage is, which together decide what a year of work is worth.

City prices and rents

Asking prices, rents, Hausgeld and local salaries per city. Each set carries the date it describes, so it is not necessarily today's value.

Grunderwerbsteuer

Set by each state, not by the municipality, and wide enough that getting it wrong moves the closing costs by thousands.

Mortgage rates

The effective rate on new housing loans, monthly since 2003.

Price and rent indices

Transaction-based indices for Germany and seven cities, quarterly since 2003. Different in kind from asking prices, and used for a different thing.

Fund returns and fees

Long-run return, volatility and ongoing charge for each fund, each with the window it was measured over.

Inflation

The planning assumption for a long projection: 2%, which is the German 25-year average and what the ECB targets. The consumer price index is checked every day, and a note appears if the average drifts far from 2%.

Tax on investment gains

Abgeltungsteuer plus the solidarity surcharge, less the Teilfreistellung an equity fund gets.