Open the TVM Solver
On a TI-84 Plus or TI-84 Plus CE
- Press APPS and choose 1: Finance.
- Choose 1: TVM Solver.
- Move the cursor to the unknown and press ALPHA, then ENTER, to solve.
| Field | What to enter |
|---|---|
| N | The number of payments or periods, not the number of years |
| I% | The annual interest rate as a percent, such as 6 for 6% |
| PV | The amount today. A loan you receive is positive |
| PMT | The payment each period. Payments you make are negative |
| FV | The amount at the end, such as a balance you reach or a balloon payment |
| P/Y and C/Y | Payments per year and compounding periods per year, both 12 for monthly |
| PMT: END or BEGIN | END if payments come at the end of each period, BEGIN if at the start |
Example 1: a car loan payment
You borrow $20,000 at 6% a year for 5 years, with monthly payments at the end of each month. What is the payment?
| Field | Entry |
|---|---|
| N | 60 |
| I% | 6 |
| PV | 20000 |
| PMT | Solve for this |
| FV | 0 |
| P/Y and C/Y | 12 and 12 |
| PMT mode | END |
The solver returns PMT = -386.66. The negative sign means you pay it out each month. Over 60 payments you pay about $23,199, so about $3,199 of that is interest. If your payments came at the start of each month, switching the mode to BEGIN changes the payment to $384.73.
Example 2: saving for the future
You deposit $300 at the end of every month for 20 years and earn 7% a year, compounded monthly. How much do you have at the end?
| Field | Entry |
|---|---|
| N | 240 |
| I% | 7 |
| PV | 0 |
| PMT | -300 |
| FV | Solve for this |
| P/Y and C/Y | 12 and 12 |
| PMT mode | END |
The solver returns FV = 156,278.00, so you end up with about $156,278. You put in $72,000 of your own money, and the rest is interest.
The traps that give wrong answers
- Signs. You need one cash flow going out and one coming in. If PV and PMT have the same sign when you solve for the rate, the calculator cannot find an answer.
- N counts payments. A 5-year monthly loan is N = 60, not 5.
- Leftover numbers from the last problem. Reset the fields you are not using to 0 before you start.
- P/Y and C/Y. If they do not match the problem, the interest is wrong. Check both every time.
- END versus BEGIN. An annuity due, where payments start right away, needs BEGIN.