FREE TOOLS · BY TWELVE DIGITAL
Tools that just work.
Focused web utilities — for German tax & finance, PDFs, and solar yield. Each one does a single job, loads instantly, and runs right in your browser.
Featured tools
Rechenwerk
rechenwerk.twelve-tools.com
Free online calculators for German tax & finance.
Severance pay with Fünftelregelung, property transfer tax across all 16 federal states, garnishment limits per §850c ZPO, and tax progression from wage replacement. Four standalone calculators, each referencing the underlying §EStG / ZPO law.
Open Rechenwerk →PDF Tools
pdf-tools.twelve-tools.com
Merge and split PDFs in your browser.
Combine several PDFs into one document, or pull specific pages out of an existing file. Files are processed locally with the open-source pdf-lib engine — they never leave your laptop. Handles documents of hundreds of pages without breaking a sweat.
Open PDF Tools →Solar Simulator
solar.twelve-tools.com
Photovoltaic yield, powered by EU JRC PVGIS.
Configure your roof, tilt, azimuth, and location and see annual, monthly, and daily AC output instantly. Backed by the European Commission's reference irradiance dataset and useful for sizing a residential PV system before talking to an installer.
Open Solar Simulator →Why focused tools?
Every tool here does one job. We don't try to be a platform, a workspace, or an account-system. You arrive at a URL, the calculation or transformation happens, you leave with the result. No onboarding, no dashboard, no upsell.
That focus has consequences we like. The pages load fast because they ship almost nothing. They run in your browser so the data stays on your machine where the file processing makes that possible. They survive without our servers being up — open the page once, your laptop has the engine cached. And they age gracefully: a single-purpose tool gets sharper with each iteration instead of bloated with unrelated features.
Twelve Tools is the tools portal of Twelve Digital GmbH. We build small, focused web utilities from Munich — each one runs on its own subdomain with independent infrastructure.