Present Value and Future Value
Compounding, Discount Rates, and the Time Value of Money — A TLDR Primer
Compound interest, present value, discount rates, annuities — these concepts show up in precalculus, personal finance, economics, and standardized exams, and most students hit them without any real preparation. A single confusing lecture or a dense textbook chapter can leave you guessing on problems you should be solving cold.
**TLDR: Present Value and Future Value** cuts straight to what matters. It builds the time value of money from the ground up — starting with why a dollar today is worth more than a dollar tomorrow, then developing the future value and present value formulas step by step, with worked numerical examples at every stage. From there it covers compounding frequency, nominal versus effective rates, continuous compounding with *e*, and finally annuity formulas for loans and savings problems.
This guide is written for high school students in precalculus, personal finance, or introductory economics, and for college freshmen who need a clean foundation before a finance or accounting course. It is short by design — no filler, no detours, just the core ideas, the formulas, worked examples, and the pitfalls that most students trip over.
If you need to understand present value and future value for a test next week or a class starting Monday, this is the place to start. Pick it up and get oriented today.
- Explain why a dollar today is worth more than a dollar tomorrow
- Compute future value with simple and compound interest
- Compute present value by discounting future cash flows
- Handle multiple compounding periods per year, including continuous compounding
- Value streams of payments using annuity formulas
- Recognize and avoid common mistakes when comparing cash flows
- 1. The Time Value of MoneyIntroduces why timing matters for money and sets up the core variables: present value, future value, interest rate, and number of periods.
- 2. Future Value: Simple and Compound InterestDevelops the future value formula starting from simple interest, then builds up to compound interest with worked numerical examples.
- 3. Present Value: Discounting the FutureInverts the future value formula to value future cash flows today, introducing the discount rate and showing how it answers 'what is this worth now?'
- 4. Compounding Frequency and Continuous CompoundingExtends the formulas to multiple compounding periods per year, defines nominal vs effective rates, and derives the continuous compounding limit with e.
- 5. Annuities: Streams of PaymentsHandles repeated equal payments using ordinary annuity formulas for both PV and FV, with examples like loans and retirement savings.
- 6. Putting It Together: Decisions and PitfallsApplies PV/FV to real comparisons (lump sum vs payments, lottery payouts, mortgages) and flags the most common student mistakes.