# HP-12C financial calculator online

> On an HP-12C financial calculator, you store four values in the n, i, PV, PMT, and FV keys and press the fifth key to solve. Money you receive is positive and money you pay out is negative (the CHS key flips the sign). Entering 12 n, 1 i, and 10,000 PV, then PMT, shows −888.49. The page runs the same math in the browser.

Source: https://www.calterix.com/en-us/calculator/financial/hp-12c/ · Updated 11/06/2026 · en-US

## The financial keys and the fields

A handheld financial calculator solves the same equation as the [financial calculator](https://www.calterix.com/en-us/calculator/financial/) here, but it asks for signs. Each key stores one number, and the fifth comes out of the math.

| Key | Field | What to enter |
| --- | --- | --- |
| n | n | Number of periods (months, for a monthly rate) |
| i | i | Rate per period, in percent (1 for 1%) |
| PV | PV | Present value, with a sign |
| PMT | PMT | Payment each period, with a sign |
| FV | FV | Future value, with a sign |
| CHS | Sign | Flips positive and negative |
| g BEG, g END | Mode | Payment at the start or the end of the period |

On the real calculator, the n and i keys have a second function that saves typing: g 12× on the n key turns years into months, and g 12÷ on the i key turns a yearly rate into a monthly one.

> HP is a trademark of its owner. This page is not affiliated with HP and only reproduces the calculation, which is standard financial math.

## Step by step: a $10,000 loan

1. Type 12 and press n.
2. Type 1 and press i.
3. Type 10,000 and press PV. You receive the money, so it stays positive.
4. Keep FV at 0, since the loan is paid off at the end.
5. Press PMT. The display shows −888.49, the payment, which is money going out.

On this page, leave "Key to solve" on PMT and use the default values. Switch the mode to BEG, and the payment becomes −879.69.

Mortgage-style example: a $300,000 loan at 6.5% a year for 30 years. Press 30 g n (360), 6.5 g i (0.5417), 300,000 PV, then PMT. The display shows −1,896.20. The rate is only an example.

## Signs and the most common errors

- Sign error: PV and PMT with the same sign (both positive) have no solution, because money never goes both in and out. This is the most common cause of an error on a financial calculator.
- Rate as a fraction: type 1 for 1%, not 0.01.
- Wrong mode: a regular loan uses END. Rent paid in advance uses BEG. A leftover BEG from an earlier problem is a classic mistake.
- Yearly rate with monthly payments: divide the yearly rate by 12 first, or use g 12÷.

| Situation | PV | PMT | FV |
| --- | --- | --- | --- |
| Loan | + (you receive) | − (you pay) | 0 |
| Savings with deposits | − (you put in) | − (you deposit) | + (you withdraw) |
| One lump sum | − (you put in) | 0 | + (you withdraw) |

## Frequently asked questions

### How do I calculate a loan payment on an HP-12C?

Enter the number of payments in n, the rate per period in i, and the loan in PV, then press PMT. For $10,000, 12 months, and 1% a month, the display shows −888.49.

### Why does the HP-12C show a negative payment?

The payment is money going out. The calculator uses positive for cash in and negative for cash out.

### How do I put the HP-12C in BEG mode?

Press g, then the 7 key (BEG). The display shows BEGIN. To go back to END, press g and the 8 key.

### What does Error 5 mean on a financial calculator?

Error 5 means the values cannot be solved, usually because of the signs on PV, PMT, and FV. Use CHS to flip one of them so there is both a cash in and a cash out.

### Is there a free online HP-12C style calculator?

Yes. This page works in your browser and needs no download. For a version without signs, with Loan and Savings tabs, see the [financial calculator](https://www.calterix.com/en-us/calculator/financial/).