The new Decision Engine: how Obolus turns tools into one financial flow

Obolus started as a set of strong standalone tools. That was useful, but it also created friction: users often got a result and then had to decide on their own what to do next.

The new Decision Engine changes that. Instead of showing isolated tools, each relevant page now follows the same product logic:

1. State: your current scenario stays visible.
2. Interpretation: the page tells you what the result actually means.
3. Action: one recommended next step moves the journey forward.

That turns separate calculators into one guided financial system.

Why we introduced it

Most people do not want more dashboards. They want clarity.

If you calculate your net income, the real question is not just "What is my net pay?" The real question is:

• How well does that income hold up in everyday life?
• How much disappears into rent?
• Would the same offer work better in another country?
• What plan can I actually build from it?

The Decision Engine is designed to answer exactly those questions in sequence.

The new flow across the product

The system now follows one clearer path:

Net pay -> Cost of living -> Housing pressure -> Tax comparison -> Budget -> Cockpit -> Invest

Each step has a distinct job:

• TaxApp sets your net baseline.
• Cost of Living shows what remains after rent and everyday costs.
• Rent vs Income isolates housing pressure.
• TaxCompare separates tax effects from day-to-day affordability.
• Budget turns the scenario into a monthly plan.
• Cockpit turns that plan into a living system.

From there, the final step is Invest, where free monthly cash can be tested as a long-term wealth path.

What changed in the interface

The biggest change is not a new feature. It is a new structure.

1. Scenario Bar

The compact scenario bar keeps the current case visible across the flow.

Examples:

• DE · EUR 53,000 -> EUR 33,928 net
• EUR 260 free / month

This makes the active scenario feel continuous instead of reset on every page.

2. Decision Layer

Above the fold, pages now focus on one key takeaway.

Instead of long tool intros or too many competing options, the page shows:

• your result
• what it means
• why it matters now

For example, a cost-of-living page should not just say that one country ranks higher. It should tell you which country gives you the stronger day-to-day buffer and by roughly how much.

3. One Recommended Next Step

This is the core of the new system.

Each step now tries to show one obvious next action instead of a broad menu.

Examples:

• after net pay: check cost of living
• after cost of living: build a financial plan
• after budget: save the plan in the cockpit
• after cockpit: start invest

That makes the product feel guided instead of scattered.

Why this matters

The Decision Engine is a UX change, but it is also a product identity change.

Before, Obolus could feel like:

• a tax calculator
• a comparison tool
• a budgeting app
• an invest simulator

Now it is much closer to one connected system for real financial decisions around work, location, and long-term planning.

That matters especially for:

• relocation decisions
• expat planning
• salary negotiations
• housing trade-offs
• savings and investing follow-through

The product principle behind it

The underlying principle is simple:

State -> interpretation -> next state

That means each page should do more than display data. It should help users decide what to do with that data.

We believe this is the more useful direction for modern finance products. Fewer menus. Fewer dead ends. More momentum.

What comes next

The current rollout introduced the system across the main journey pages. The next steps are about refinement:

• sharper copy per step
• better decision summaries
• more consistent handoff of scenario values
• stronger account-saving moments in Cockpit
• tighter links between Budget and Invest

Conclusion

The new Decision Engine is not a cosmetic layer. It is the connective tissue of the product.

Instead of asking users to navigate a collection of tools, Obolus now does more of the sequencing itself:

calculate the result, interpret it, and move to the next meaningful step.

That is the direction we want to keep building.

Tax Return 2026: deadlines, documents, and a 7-step checklist

People searching for "tax return deadline 2026" usually want a practical plan, not abstract tax theory. This article gives a simple sequence you can follow.

1) Put your deadline in the calendar

Even if you submit later, setting an early planning date helps you avoid last-minute stress.

2) Sort paperwork into three buckets

Use a minimal structure:

• Income (salary statements, side income)
• Expenses (work-related costs, special expenses, extraordinary burdens)
• Household/family (childcare, household services, craftsman invoices)

3) Review work-related expenses in detail

Many filers stop at the lump sum even when they could claim more:

• commuting
• equipment
• training
• home-office days

4) Double-check special expenses and insurance

Insurance and pension-related items are easy to underreport. A quick check against annual statements can improve results.

5) Include family-related tax items

Family costs are often spread across the year. Keeping one dedicated folder makes year-end filing faster.

6) Prepare digital filing

ELSTER lets you submit online and reuse parts of previous filings.

7) Compare the final tax notice

After submission, verify the tax notice:

• Were all positions recognized?
• Are there major differences?
• Is an objection worth considering?

Conclusion

A clear workflow beats last-minute filing: organize, file, verify. That is usually the fastest path to less stress and better refund outcomes.

New feature: spousal splitting as a simulation

Some time ago, we published the article Spousal Splitting in International Comparison to explain where the German splitting model comes from, why it remains controversial, and why tax class choices for married couples often create the wrong incentives. The next step was not another theory piece. It was a tool.

With the new Joint Tax Filing Simulation, you can now see directly how the German splitting model compares with a more individualized tax treatment.

What the new feature does

This page is not just another static explainer and not a classic payroll form. It is a simulation layer for one of the most debated parts of German income tax policy:

• How large is the tax advantage created by the splitting system?
• How does the burden change when incomes are very uneven?
• What happens if the model is reduced, changed or removed?

That is exactly where simulation is more useful than a single example. Instead of one number, you get a clearer view of the pattern behind the policy.

Why this matters

Debates around spousal splitting often jump straight into ideology: does it support families, does it freeze old role models, does it weaken incentives for secondary earners? Those questions matter, but for most households the first question is simpler:

What does this mean for our actual income?

That is the gap this new page closes. It turns an abstract tax-law debate into something easier to read financially.

How this connects to the older blog post

The earlier article focused on three things:

1. the legal and historical background of the splitting system
2. the criticism around labor-market and second-earner incentives
3. the practical differences between tax class 3/5 and 4/4 with factor

The new simulation adds the missing layer. It no longer only asks how the system works. It asks how strong the effect really is under different income distributions.

So the older post still matters. It now works as the conceptual background, while the simulation becomes the practical front end.

Who should use it

This feature is useful well beyond pure tax specialists. It is especially relevant for:

• married couples with a large income gap
• households planning a return to part-time or full-time work
• users following reform debates who want to understand the real financial magnitude
• journalists, advisors and policy-interested readers who need a better intuition for the size of the effect

The more uneven the income split inside the household, the more revealing the simulation becomes.

What to test first

When you open the Joint Tax Filing Simulation, it helps to compare more than one setup:

• a strongly asymmetric income pair
• two similar salaries
• middle-income and higher-income scenarios

That is the fastest way to see where the splitting effect is large, where it almost disappears, and where reform proposals become economically meaningful.

Why we built it

Obolus should not only provide calculators. It should also provide explanation tools that help people reason through policy and household choices. Spousal splitting is exactly the kind of topic where users need more than one static article.

That is why this feature is visual first. It is meant to create orientation before users dive into technical detail.

Conclusion

If you already know the older article, the new Joint Tax Filing Simulation is the natural continuation. If you are new to the topic, you can start with the simulation and then read the background article here.

That combination is the real upgrade:

• first see the effect
• then understand the system
• then judge your own household case more clearly

Federal Budget 2026: Understand Public Finance Visually

At first glance, the federal budget looks like an endless table. With our interactive view at Federal Budget 2026, you can read revenue and spending as flows and jump directly into detail.

What you see in the chart

• Left: Revenue
• Center: Total revenue and total spending
• Right: Spending

You can switch between a compact 1-level view and a 2-level view. In 2-level mode, you only open level 3 when needed by clicking a node.

Drilldown without number overload

Instead of showing everything at once, you move step by step through the hierarchy:

1. Plan
2. Chapter
3. Title

This makes it easier to spot the largest budget blocks and separate major streams from minor details.

Compact value formatting

Values are shown in a compact way:

• Above 1 billion: Billion Euro
• Above 1 million: Million Euro

So you can compare magnitudes instantly without scanning long number strings.

Why this matters

The federal budget is not abstract policy only. It directly affects taxes, transfers, infrastructure, and social systems. If you understand the structure, you can evaluate political priorities much more clearly.

If you want a quick start, begin in the 1-level view, zoom into the largest nodes, then switch to 2 levels for deeper analysis.

Master Your Net Worth

Financial planning used to be about looking in the rearview mirror. With our latest update, we’re transforming your dashboard into a true Financial Cockpit that doesn't just show where you are, but where you're headed.

What’s New?

We’ve overhauled three core areas to provide the depth of insight usually reserved for professional portfolio managers.

1. Income Waterfall Analysis

Finally understand where your money goes. Our new IncomeOverview widget visualizes the journey from gross income to disposable cash.

• Transparency: Automatic calculation of taxes and social contributions.
• Disposable Focus: Real-time view of your monthly "fun money" after fixed expenses.

2. Asset Performance 2.0 (CAGR & Total Return)

An asset is only as good as its return. In the new overview, we now track:

• Total Return: Your absolute performance since inception.
• CAGR (Compound Annual Growth Rate): The annualized growth rate to finally make Crypto, ETFs, and Real Estate comparable.

3. Smart Savings Tracking

Your savings rate is the most important lever for wealth creation. Our new widget doesn't just show your current rate—it provides 5 and 10-year projections instantly.

Technical Deep Dive: Database Support

Thanks to our new database integration, your profiles and scenarios are now securely stored. This enables:

• Historical Comparisons: See how your savings rate has improved over the last year.
• Multi-Asset Support: From stock tickers to manual real estate entries, everything stays in sync.

Borderless Financial Planning

Obolus has evolved. What started as a dedicated tool for German wage tax has now transformed into a comprehensive Global Finance Suite. In an era of global mobility, your financial tools should be as flexible as your career.

Full Support for 8 Key Jurisdictions

We have integrated deep tax logic for the most sought-after international locations:

• Europe: 🇩🇪 Germany (2026 Update), 🇦🇹 Austria, 🇨🇭 Switzerland, 🇮🇪 Ireland
• Global: 🇺🇸 USA, 🇬🇧 UK, 🇨🇦 Canada, 🇦🇺 Australia

Introducing TaxCompare

The highlight of this shift is our new /taxcompare page. It allows you to visualize the tax burden across all 8 supported countries at a single glance. It’s the perfect dashboard for expats and nomads to optimize their take-home pay.

The Financial Ecosystem

This update connects the dots of your financial journey:

1. TaxApp: Calculate your accurate net income worldwide.
2. Budgeting: Seamlessly import your income into your personal budget.
3. Investing: Project your wealth based on actual, tax-adjusted savings.

The future of Obolus is global. Welcome to borderless finance.

Furthermore, this new functionality also offers new statistical possibilities.

Here, for example, are the tax rates of a single person without children in international comparison:

A frequent claim in tax debates is that only a small high-income group carries a disproportionately large share of financing. A look at wage and income tax statistics supports that the burden is highly concentrated.

The distribution chart (“tax segments & shares”) highlights the asymmetry:

• Broad base: lower income groups contribute comparatively little income tax because of the basic allowance and progressive entry zones.
• Top segments: burden concentration rises sharply toward the top of the income ladder.

The income-millionaire segment (gross income above €1 million) represents only about 0.1% of taxpayers but contributes roughly 9.9% of total income tax.

Adding the next segment (€500k to €1 million) brings another 0.2% of taxpayers and around 5.5% of revenue.

If the top three segments are combined (roughly incomes above €250k), they represent about 1.0% of taxpayers and contribute around 25.2% of total income tax revenue.

This concentration has two sides:

• It reflects redistribution through a progressive tariff (“strong shoulders carry more”).
• It also creates concentration risk for public budgets if this small tax base weakens cyclically or migrates.

Planning with a view to 2026

You can now calculate the 2026 tax year in our tax calculator. The calculation uses the currently legally valid 2026 tax logic.

This update helps you simulate how current tax and contribution changes may affect your personal net income.

Legally valid tax logic for 2026

The 2026 adjustments are mainly designed to compensate for “cold progression”. This effect occurs when tax burdens rise even though real purchasing power stagnates or falls.

The core measures are:

• Higher basic tax-free allowance: from €12,096 to €12,348 (approx. +2%)
• Shifted tax brackets: marginal rates apply at higher income levels

These changes are intended to prevent inflation-only wage increases from creating a disproportionate tax burden.

Example: Relief for single taxpayers

The effects are often especially visible for single households. With a higher allowance and shifted brackets, a larger share of income remains untaxed or taxed at lower rates.

At the same time, higher incomes are affected by increased social contribution ceilings from 2026:

• Health and long-term care ceiling: €66,150 → €69,750 (approx. +5.4%)
• Pension and unemployment ceiling: €96,600 → €101,400 (approx. +4.9%)

Our updated 2026 calculator shows how these effects can look in individual cases for singles, married households and single parents.

Conclusion

If you want forward-looking tax and financial planning, you can already model scenarios with currently valid 2026 rules.

Try it now: https://www.obolusfinanz.de/en/taxapp

Introduction

The so-called spousal splitting (Ehegattensplitting) is a central component of German income tax law. It regulates how married couples or registered partners can be taxed jointly. At its core, the splitting procedure means that the total taxable income of both partners is added together, then halved, and taxed according to the progressive tax rate. The tax for the halved income is then doubled. This method "smooths" the tax progression and provides tax relief for households with significantly different income levels.

Historical Background

Spousal splitting was introduced in 1958 after the Federal Constitutional Court declared the previous "household taxation" system unconstitutional. The judges argued that tax law must recognize marriage as an equal partnership. With splitting, the legislature aimed to ensure that married couples would not be in a worse tax position than single individuals.

Over the decades, the splitting procedure has become a permanent part of German tax law, yet it has faced increasing controversy. Critics see it as favoring traditional role models where one partner earns the main income and the other works little or not at all. For secondary earners, often women, the model can bring financial disadvantages and make employment less attractive.

International Comparisons

A look abroad shows that Germany is rather an exception with its splitting procedure.

France: Here, the "Quotient Familial" is used, which considers not only the income of spouses but also children. The income is divided by "family shares" and then taxed, which particularly benefits large families.

USA: Married couples can choose between joint filing and separate filing. Under the joint filing option, they benefit from more favorable tax brackets, though to a lesser extent than in Germany.

Austria & Scandinavia: These countries follow the principle of individual taxation. Each spouse is taxed independently of the other; only child and family allowances provide tax relief.

Germany is therefore one of the few countries that practice joint taxation with significant benefits for couples with income disparities.

Criticism and Discussion

Proponents see splitting as an important recognition of marriage and a relief for families. Opponents criticize that it benefits households without children just as much as families with children. Furthermore, it reinforces the "sole earner + secondary earner" model and hinders equality in the labor market.

Choosing Tax Classes for Married Couples

In addition to the splitting procedure, the choice of tax classes also plays a role in Germany. Married couples can choose between the combinations IV/IV and III/V:

Combination IV/IV: Both partners are treated equally. This is particularly useful when incomes are similar. A factor must be specified. How this is calculated is often intimidating, but later in this article, we will show you how to calculate this value comprehensibly.

Combination III/V: The higher-earning partner benefits from lower monthly deductions (Class III), while the lower-earning partner is more heavily burdened (Class V). This often leads to a higher monthly household net income but can result in tax payments at the annual tax return.

The final tax liability is calculated anyway within the annual income tax return using the splitting procedure. Which model is more beneficial in practice depends on the income ratio—this is where a calculation example comes in handy to illustrate the differences. We use our gross-to-net calculator to compare two typical income scenarios for a married couple:

Partner 1 Income: €60,000 - Partner 2 Income: €20,000

Tax Result Tax Class 3+5

Tax liability prepaid: €7,333. Tax liability at settlement: €9,036. A supplementary payment of €1,703 is to be expected. (Normally, a prepayment for the next tax settlement is set by the tax office from a supplementary payment of €400.)

Tax Result Tax Class 4+4 Factor 1

Tax liability prepaid: €9,997. Tax liability at settlement: €9,036. A tax refund of €961 is to be expected.

If we now look at the factor field in the app, we see a calculated value:

Here we can read the value that allows us to achieve a payroll deduction adjusted to the expected tax liability.

The result then looks like this:

Tax liability prepaid: €9,037. Tax liability at settlement: €9,036. A tax refund of €1 is to be expected.

You can register the calculated factor with your tax office to achieve a more suitable adjustment.

Conclusion

It must be stated that spousal splitting with tax classes 3/5 provides some relief for certain family constellations. However, this relief is often only a pleasant effect on the monthly payroll deduction, while the annual tax settlement often results in unpleasant supplementary payments and subsequent prepayments. The proposed solution, tax class 4/4 with a factor, is a viable one. However, setting a static factor is initially complex and opaque. Afterward, it is a secure solution as the tax prepayment aligns with the tax liability. However, problems arise when the income ratio between the spouses changes. In that case, the factor needs to be adjusted regularly.

This is particularly common for spouses with young children and resulting childcare responsibilities.