TOOLS / THE EVERYDAY WORKBENCH
A useful kind of curiosity.
Small, inspectable tools for a working day. Calculations stay in your browser. Inputs, assumptions and results are visible.
01 / + − × ÷
Calculator
Everyday arithmetic, with powers and square roots.
Controls and calculation rules
Type an expression or use the keys. Enter calculates; Escape clears.
% divides a value by 100. For example, 200 × 10% = 20. To add 10%, use 200 × (1 + 10%).
Results use up to 12 significant digits. Calculations stay in your browser.
02 / EUR
Loan planner
Follow a fixed-rate loan from the first payment to the last cent.
Repayment schedule
| Month | Payment | Total interest | Principal | Balance |
|---|
Monthly payments in arrears. Interest and payments round to cents each month; the final payment clears the balance. No fees, rate changes or early repayments. This is a model, not a lender’s quotation.
03 / DE · 2026
German income tax · 2026
Estimate the basic statutory tariff from taxable income, with the rounding made explicit.
2026 §32a EStG only. Taxable income is not gross salary. Excludes solidarity surcharge, church tax, social insurance, credits, progression proviso and special tariffs. Joint eligibility is assumed. Not tax advice.
Taxable income and the resulting tariff tax are rounded down to whole euros. Joint assessment is twice the rounded tariff tax on half the combined income.
Formula source / §32a EStG ↗04 / DC
Loaded voltage divider
See why a load changes the voltage you expected—and what resistor tolerance does to it.
Ideal DC resistors; independent R₁/R₂ tolerances, exact input voltage and load. No thermal or supply variation. Check real component ratings before building a circuit.
Focus timer
Focus
Uses an end timestamp to stay accurate in background tabs. A suspended browser cannot guarantee an alarm. The next session starts when you choose. Changing the paused current session’s duration resets that session; changing the other duration preserves your progress.