Finance & Currencies

Currencies, VAT, compound interest — 100% local.

Exchange rates (indicative, editable — CHF base)

Indicative rates — update them yourself according to the day's rate (Google, your bank, etc.). This tool doesn't connect to any server, staying 100% local.

Conversion

Result
Net amount
VAT amount
Gross amount
Final amount
Total contributed
Interest earned

Capital growth

All calculations are performed entirely in your browser. These tools are indicative and do not replace professional accounting, tax or financial advice.

Converting currencies offline

An exchange rate is not a constant: it moves continuously and differs depending on whether you look at the interbank rate, your bank's rate or a bureau de change. This module connects to no service, to stay 100 % local — you enter the day's rate yourself (bank, search engine, app) and the tool applies the conversion. Useful for planning a travel budget or checking an invoice, keeping in mind that a 1 to 3 % gap between the displayed rate and the rate actually charged is common.

VAT: adding is not removing

Going from a price excluding tax (excl.) to a price including tax (incl.) is done by multiplying. The reverse operation is not subtracting the same percentage.

incl. = excl. × (1 + t)  ·  excl. = incl. ÷ (1 + t)

Example at the standard Swiss rate (8.1 %): 100 CHF excl. gives 108.10 CHF incl. But a price of 100 CHF incl. corresponds to 92.51 CHF excl., i.e. 7.49 CHF of VAT — not 8.10. The tool handles both directions and offers the Swiss rates (8.1 % / 2.6 % / 3.8 %) as well as the standard rates of several EU countries.

Compound interest: the effect of time

Invested capital produces interest which, reinvested, produces interest in turn. Growth is therefore not linear but exponential.

Vₙ = V₀ × (1 + r/m)^(m·n)

where V₀ is the initial capital, r the annual rate, m the number of compounding periods per year and n the number of years. The higher m (monthly rather than annually), the larger the result, but the gap stays modest. The "contribution per period" field adds a regular amount at each due date: that's what separates active saving from a dormant investment.

Rule of thumb: at 5 % a year, capital doubles in about 14 years; at 7 %, in 10. The "rule of 72" gives a good approximation: 72 ÷ rate ≈ number of years to double.

Frequently asked questions

Why aren't exchange rates automatic?

Fetching a live rate would mean querying a third-party server on every visit. The site's principle is that no data leaves the browser: you enter the rate, the tool calculates.

Does the interest simulator account for inflation or tax?

No. It shows gross nominal growth. Inflation and taxation (income tax, withholding tax) reduce the real return and depend on your situation.

Do these results count as financial advice?

No. They are educational orders of magnitude. An investment decision or a tax return must rely on a professional.