Compound Interest Calculator
Model compound interest with configurable principal, rate, compounding frequency, and additional contributions. Interactive growth chart with year-by-year breakdown.
You don't control software you don't possess
The Finance Knife is the answer
Terms change. Features disappear. Accounts get suspended. Servers go down. When you depend on someone else's infrastructure, you depend on their decisions. Sovereign tools. Single HTML files you own. No accounts, no terms, no kill switch.
The Finance Knife is a single-file knife with 10 tools that runs entirely in your browser. 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 solve the digital sovereignty problem?
The Finance Knife runs entirely in your browser. Terms change. Features disappear. Accounts get suspended. Servers go down. When you depend on someone else's infrastructure, you depend on their decisions. Sovereign tools. Single HTML files you own. No accounts, no terms, no kill switch. 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.
Is my data safe with The Finance Knife?
Yes. The Finance Knife is a single HTML file. It never connects to any server. Your data stays in your browser's local storage on your device.
What makes The Finance Knife different from cloud tools?
Cloud tools require internet, charge subscriptions, and store your data externally. The Finance Knife is a one-time purchase ($39), works offline, and never transmits data.
Is The Finance Knife really just one file?
Yes. The Finance Knife is a single HTML file containing 10 tools. Download it, open it in any browser, and start working. No installation, no dependencies, no accounts.
No cloud One fileOne-time purchase
Get The Finance Knife — $39Sovereignty as a Service