Skip to content
Tool·Lifes /Compound & the power of time
Apps
Explore Guides Search
⌛ Foundations

Time value of money

A dollar today is not a dollar in ten years — discounting, present value and why waiting has a price.

Time value of money says cash flows must be dated: earlier money can be invested, so later money is worth less in present terms unless discounted.

Time value of money sits in the foundations family of this atlas: mechanisms first, products second, hype never.

Use the calculator for scenarios, then return to the section pages when you want the vocabulary behind the curve.

LensPresent value
ToolDiscount rate
SiblingOpportunity cost
UseCapital budgeting
TrapIgnoring inflation
ToneEducational

Profile

Time sensitivity
94
Rate sensitivity
90
Contribution leverage
48
Behaviour risk
40
Tax & fee drag
55
Horizon fit
85

Seven chapters

The idea

Time value of money says cash flows must be dated: earlier money can be invested, so later money is worth less in present terms unless discounted.

Read →

The math

Formulas, worked examples and rules of thumb for time value of money, with inflation and fees kept in view.

Read →

Levers

What you can actually pull when thinking about time value of money: contributions, time, costs, behaviour and wrappers.

Read →

History

A short history of ideas and institutions behind time value of money.

Read →

Pitfalls

Common traps and myths around time value of money, with practical fixes.

Read →

Practice

A practical sequence for applying time value of money without turning life into a spreadsheet cult.

Read →

Today

Modern context for time value of money: rates regimes, apps, FIRE debates and longevity.

Read →

Frequently asked questions

What is time value of money in one sentence?
Time value of money says cash flows must be dated: earlier money can be invested, so later money is worth less in present terms unless discounted.
Is this financial advice?
No. Tool-Lifes pages are educational atlases. Decisions need your goals, constraints and, when appropriate, a licensed adviser.
Do I need a high return for compounding to matter?
Higher net rates help, but time and contributions often dominate — especially early. Costs and behaviour can erase a “good” rate.
How should I use the calculator?
Treat outputs as scenario sketches. Vary contribution, rate, fees and inflation to see which lever moves your goal date.
What about inflation?
Always ask whether a figure is nominal or real. A high nominal path can still lose purchasing power.
Are past returns a promise?
No. Illustrations use round teaching numbers. Markets, inflation and taxes change.
Where do fees show up?
In the net rate that compounds. Expense ratios, advice charges and spreads all reduce terminal wealth.
What page should I read next?
From foundations, continue to contributions-vs-rate or fee-drag; for behaviour, open consistency-habit or panic-selling.

Open calculator →