Many financial decisions look small.
The long term effects are not.

The Long Math is an independent website providing tools and explanations that make the long-term arithmetic of personal financial decisions visible.

No opinions. No hidden assumptions. Just arithmetic.

One small percentage. One very large difference.

See how fees affect $500,000 invested for 30 years at 7%

No advisory fee $3,806,122
1% advisory fee $2,871,745
Difference $934,377

A small annual percentage becomes a very large number when compounded over decades.

See the full calculation →

Adjust the fee

Management fee
No fee (7% annual return) $3,806,122
With selected fee $2,871,745
Cost of fee $934,377

Illustrative annual compounding over 30 years. Slider adjusts the fee in the model only.

Explore the Long Math

Calculators

Interactive models that show how fees, taxes, inflation, and time interact over decades.

  • Cost of a Financial Advisor
  • Pay Off Mortgage vs Invest
  • Inflation Time Machine
  • TFSA Contribution Room
  • Lots more calculators covering Canadian taxes and payroll, amortization with semi-annual mortgage rate conversion, registered-account combos, withdrawals, incorporation, capital gains, student debt, inflation-adjusted growth, behavioural fee scenarios...
Explore Calculators →

Understanding

Clear explanations of the concepts behind investing and long-term financial arithmetic.

  • Compound Interest
  • Inflation
  • What Is Investing
  • What Is a Stock
  • What Is the Stock Market
  • Asset Classes
  • Lots more explanatory articles covering registered-account rules, ETFs, diversification, behavioural biases, sequencing risk near retirement, mortgage mechanics, leveraged strategies, and RESP basics among other topics.
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Beyond the Numbers

Essays on careers, training pipelines, long-horizon trade-offs, and the financial arithmetic behind building a professional life.

The early essays focus on medicine — the author's professional world — but the section will expand into other career structures, training pipelines, and major life decisions where long-horizon arithmetic shapes the outcome.

Read Essays →

Questions the Long Math Can Answer

Examples of questions this site addresses using explicit assumptions and inspectable arithmetic:

Inspectable Arithmetic

Financial conclusions are often presented without the math behind them. The Long Math focuses on the arithmetic itself.

Every model on this site shows:

  • the formulas used
  • the assumptions used
  • the inputs used

Nothing is hidden.

Start Here

If you are new to investing, begin with these ideas:

Browse Understanding →

More Models Over Time

Future tools will explore long-term financial arithmetic in areas such as:

  • taxes
  • corporate vs personal investing
  • investment fee structures
  • long-term financial scenarios

The goal remains the same: make the arithmetic visible.

Start with the math.

Explore the arithmetic behind financial decisions.