Finance
Browse 6 professional tools
Compound Interest Calculator
Inflation Calculator
Invoice Generator
Loan Calculator
Precious Metals Prices
Tip Calculator
Finance tools cover the math behind common personal finance decisions — loan amortization, compound interest, currency conversion, tax-aware invoicing. The opinionated take: model in real (inflation-adjusted) terms, not nominal; understand the difference between mid-market and consumer exchange rates; tip according to local convention not global average. These are calculation tools, not financial advice.
Investments & savings
Compound interest with periodic contributions, inflation index choice (CPI-U vs Core vs Chained vs PCE — each gives a different answer), precious metals pricing by troy ounce. The rule of 72 estimates doubling time: 72 / annual rate ≈ years to double.
Calculate compound interest with visual growth chart. Compare simple vs compound interest. Monthly contributions support. Free online investment calculator
Calculate how inflation affects purchasing power over time. Historical inflation impact calculator. Free inflation rate calculator
Track gold, silver, platinum, and palladium prices. Calculate metal value by weight. Free precious metals price tracker
Debt & loans
Amortization schedule with extra-payment simulation. The surprise for most people: at the midpoint of a 30-year mortgage you still owe 78% of the principal. Early extra payments have outsize impact on total interest.
Business & invoicing
Tax-compliant invoice generation for EU (reverse charge for intra-EU B2B services), Poland (NIP/JPK_V7), US (state-specific). Currency conversion at mid-market (the wholesale reference) with explicit notes on the consumer-rate spread that banks charge.
Create professional PDF invoices with logo, line items, taxes, and totals. Free online invoice maker, no registration required. Export to PDF instantly
Real-time currency converter with live exchange rates. Convert USD, EUR, GBP, PLN, JPY and 150+ world currencies. Free forex calculator online
Everyday math
Tip calculation with country conventions (US 18-22%, Japan refused, France service-compris), percentage operations including the percent-of-percent edge cases. For "what is X% of Y" and "what % is X of Y", which trip people up surprisingly often.
Frequently asked questions
Should I plan retirement in nominal or real terms?
Real (inflation-adjusted). A $1M nominal balance in 2055 has the purchasing power of ~$550k today at 2% inflation. Long-horizon projections in nominal dollars look impressive but cannot be compared to today's cost of living. Use the Inflation Calculator to convert.
Is the gap between bank rate and mid-market significant?
Yes. Big-bank wire transfer: 2-5% off mid-market plus a flat fee. Card transactions abroad: 1-3% plus foreign-transaction fees. Wise / Revolut / Western Union: 0.4-1%. On a $1000 transfer the spread alone can be $20-50. For frequent transfers, choose a low-spread provider.
Is gold a good inflation hedge?
Over 30+ year periods, gold roughly tracks inflation. Over 5-10 year periods, it can dramatically over- or underperform. As one component of a diversified portfolio: useful. As a sole inflation hedge: insufficient. The Gold Price Tracker shows spot prices in your chosen currency.
Should I make extra mortgage payments or invest the difference?
Pure math: only make extra mortgage payments if the rate exceeds your expected after-tax investment return. At a 6.5% mortgage, extra principal is a guaranteed 6.5% return — hard to beat reliably. At 3%, the market historically beats that. Behavioral factors (sleep-at-night) often outweigh the math.
Last updated · E-Utils editorial team