Compound Interest Calculator
Model compound interest with configurable principal, rate, compounding frequency, and additional contributions. Interactive growth chart with year-by-year breakdown.
Manage Money with The Finance Knife
Money maths — no spreadsheet required
You need to manage money. Financial tools that never share your numbers. The Finance Knife delivers 10 purpose-built tools in a single HTML file.
The Finance Knife puts six essential financial calculators and a Scenario Studio into a single HTML file. Model compound interest with Oracle Mode (reverse-engineer your savings goal) and Monte Carlo simulation (see probability-weighted outcomes under volatility). Generate loan amortisation schedules with extra-payment analysis, calculate IRR and NPV, reference 20 currency exchange rates, split VAT inclusively or exclusively, and generate printable invoices — all locally in your browser. Global inflation adjustment lets you see every result in today's dollars. Your financial data never touches a server.
WHAT'S INSIDE
10 tools in a single HTML file
Oracle Mode
Reverse-engineer your financial goals — enter a target amount and get three paths (conservative, balanced, aggressive) showing the monthly contribution needed to reach it.
Monte Carlo Simulation
Run 1,000+ randomised simulations with configurable volatility to see probability-weighted outcome bands. Shows 10th/25th/50th/75th/90th percentiles and goal success probability.
Loan Amortiser
Generate full amortisation schedules for any loan — see principal vs interest breakdown for each payment, total interest paid, payoff date, and savings from extra payments.
HOW IT WORKS
Three steps. No setup.
1
Download the file
Purchase The Finance Knife and download a single HTML file. No installer, no account, no setup.
2
Open in any browser
Double-click to open in Chrome, Firefox, Safari, or Edge. Works on any operating system.
3
Start working
Your data stays in your browser's local storage. Nothing is uploaded. Ever.
COMPLIANCE & GEOGRAPHY
Global
Works in any country. No server dependency, no regional restrictions.
FAQ
Frequently Asked Questions
How does The Finance Knife help me manage money?
The Finance Knife provides 10 interconnected tools for financial tools that never share your numbers. Compound interest with Oracle Mode and Monte Carlo simulation, loan amortiser, IRR/NPV calculator, currency table, VAT/tax splitter, invoice generator, and Scenario Studio. Financial tools that never share your numbers.
Do I need an internet connection to manage money with The Finance Knife?
No. The Finance Knife runs entirely in your browser as a single HTML file. All 10 tools work offline.
What is the difference between The Finance Knife and cloud-based alternatives?
Cloud tools store your data on external servers, require subscriptions, and stop working without internet. The Finance Knife is a one-time purchase ($39) that runs locally. Your data never leaves your device.
Can I use The Finance Knife on multiple devices?
Yes. Once purchased, you can use The Finance Knife on any device with a web browser. Copy the HTML file to as many devices as you need.
No cloud One fileOne-time purchase
Get The Finance Knife — $39Sovereignty as a Service