Summatio

Summatio is a comprehensive collection of over 25 finance, real estate and tax calculators for Germany and international markets. From gross-to-net to mortgage to ETF savings plans, you will find the right calculator for every financial question.

All calculators are free to use, run entirely in the browser and do not store any personal data on servers. The calculations are optimized for the German market (tax brackets, social security contributions, real estate transfer tax by state) but also offer English versions for international users.

Summatio is aimed at everyone who wants to make informed financial decisions: employees, property buyers, landlords, savers, freelancers and parents.

Summatio offers calculators in six categories.

Salary calculators: The gross-to-net calculator computes your net salary considering tax bracket, church tax, solidarity surcharge and all social security contributions. The salary calculator converts between hourly wage, monthly salary and annual salary. The severance calculator computes the tax burden of a severance payment with the fifth rule.

Real estate calculators: The mortgage calculator computes monthly payments, total interest and remaining debt. The closing costs calculator computes real estate transfer tax (by state), notary, land registry and agent fees. The amortization schedule shows the monthly development of principal and interest over the entire term. The rent-or-buy comparison calculates whether buying or renting is financially better over 30 years.

Landlord calculators: The rental yield calculates gross and net yield of a property. The rent increase checks capping limits and rent control. The depreciation calculator computes depreciation and tax savings. The utility costs calculator calculates the annual utility bill. The property yield calculates four different yield metrics.

Savings calculators: Compound interest calculator, savings plan calculator and ETF savings plan calculator with TER, advance lump sum and partial exemption.

Tax calculators: Income tax, tax bracket comparison (3/5 vs 4/4), real estate transfer tax, inheritance tax with allowances and tax brackets.

Additional calculators: Loan calculator, debt repayment (snowball vs avalanche), inflation calculator, parental allowance calculator and hourly rate calculation for freelancers.

Each calculator offers export as PDF, image, CSV and Excel.

Summatio stands out from existing calculator portals through several features.

All calculators are interconnected. When you calculate closing costs, you can jump directly to the mortgage calculator and use the total costs as the loan amount. This linking saves time and prevents input errors.

The calculations for the German market are particularly detailed. The income tax calculator considers all tax brackets, allowances, church tax and solidarity surcharge. The closing costs calculator knows the real estate transfer tax rates of all 16 federal states.

Each calculator offers different solve modes. With the compound interest calculator you can choose to calculate end capital, duration, interest rate or starting capital, depending on which value you are looking for.

The export function creates professional documents. PDFs contain the complete result with input values, calculation details and charts. Excel exports are formatted and immediately usable.

Summatio helps in various life situations.

When buying property: Calculate closing costs, simulate financing, create amortization schedules and check whether buying is worthwhile with the rent-or-buy comparison.

For landlords: Calculate rental yield, determine depreciation tax savings, create utility bills and check rent increase margins.

In salary negotiations: Compare gross-to-net differences for various salary levels, calculate tax bracket changes and determine actual hourly wages.

For savers and investors: Calculate ETF savings plans with realistic costs (TER, taxes), visualize compound interest effects and calculate pension gaps.

For freelancers: Calculate hourly rates, estimate income tax in advance and calculate severance tax for termination agreements.

For families: Calculate parental allowance, plan inheritance tax with allowances and visualize inflation effects on savings.

Summatio is built with Next.js 15 and TypeScript as a static export. All calculations run entirely in the browser. There is no backend server.

The UI uses Tailwind CSS and shadcn/ui components. Each calculator has its own URL for SEO. The application supports German and English via next-intl.

For exports jsPDF (PDF), html2canvas (images), SheetJS (Excel) and native CSV generation are used.

The tax calculations are based on current German tax laws and are regularly updated. The Pro version is offered through LemonSqueezy with license key validation.

Summatio does not store any personal data on servers. All calculations take place exclusively in the browser. Entered salaries, property prices and other financial data never leave your computer.

Results can be saved locally. Saved calculations are stored in your browser's local IndexedDB and are only accessible to you.

In the Free Tier subtle ads are displayed via Google AdSense (after cookie consent). The Pro version is ad-free.