This is a guide on how to use HP12C calculator. If you’re using Texas Instruments BA II Plus calculator, check out our how-to guide here.
The HP12C calculator is Hewlett Packard’s longest and best-selling product, in continual production since its introduction in 1981. Due to its simple operation for key financial calculations, the calculator long ago became the de facto standard among financial professionals.
If you’re keen to use the HP12C as your financial exam calculator, this guide should help. It covers:
- a list of several fundamental HP12C uses,
- followed by 2 basic examples of how the calculator’s financial operators work,
- along with some useful tips for operating the HP12C calculator.
What Is the Reverse Polish Notation (RPN)?
Reverse Polish notation (RPN), also known as Polish postfix notation or postfix notation, is a mathematical notation in which operators follow their operands, in contrast to Polish notation (PN), in which operators precede their operands.
A simple example: if you used the HP12C to add 6 and 7, you would input “6 7 +” rather than the ‘usual’ “6 + 7”.
Although Reverse Polish Notation (RPN) – the HP12C’s mathematical notation – may initially take some getting used to, it offers some advantages over non-RPN devices.
Once you’ve developed basic knowledge of RPN, you may find its format more practical particularly for TVM problems on the exams. Research has also shown that the HP 12C could be faster and more accurate for candidates to use.
Pros and Cons of RPN
Advantages of the HP12C and RPN for the CFA exams
- Faster input. Because RPN does not need the user to input parentheses, calculations have been shown to take less time to input with RPN.
- More accurate use. Research also shows that users tend to make less input mistakes with RPN.
- Good for TVM calculations. RPN can be more practical for time value of money (TVM) calculations.
- It’s cool. The HP12C is a legendary calculator, so some candidates do like to use and appreciate it beyond its use for the CFA exams.
Disadvantages of the HP12C and RPN for the CFA exams
- May take some getting used to. Anecdotally, the RPN can take some extra time to learn.
- Less exam-based support. Because the BA II Plus calculator is much more widely-used among CFA candidates, this can mean that you may not, for example, get HP12C-specific calculator examples with your provider. You may also find that there are less candidates to ask and discuss any keystroke-related issues you may have.
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How To Use HP12C: Basic Functions You Should Know
1) Setting Decimal Places
By default, the HP12C will show only two decimals places. To modify the number of places displayed, hit the yellow [f] prefix key followed by the number of places you wish to display. For example, to display five decimal places, you would key:
The yellow [f] as well as the blue [g] key will be used quite often as they allow you to access many of the important functions available on the HP12C.
2) Arithmetic Functions
Reverse Polish Notation requires that when performing arithmetic functions, you separate the first two numbers by hitting the [Enter] key. For example, to sum 5 and 5, you would key:
To add subsequent numbers (or use any other arithmetic operator), it is not necessary to use [Enter]. For example, performing the above operation will display 10 on the calculator. To continue adding 5 you would key:
3) Clearing the Display
There are six Clear keys on the HP12C – their specific functions are listed below.
Clears contents of display
Clears statistics registers R1 – R6 and the stack registers
Clears contents of financial registers
Clears all storage registers, financial registers, stack (X,Y,Z AND T) and statistics registers but does not clear program memory
Clears any prefix you’ve entered including f, g, STO and RCL
Clears any programs stored by the user
4) Parentheses (Or Brackets)
To perform a calculation requiring parenthesis such as: (3 + 4) x (5 + 6), you would key the following:
Begin with the first parenthesis’ calculation:
Then key the second parenthesis’ calculation:
Then key [x]. The HP12C will display 77 (which is the first result, 7, multiplied by the second result, 11):
5) Percentage Differential
The HP12C has a key for calculating percent change between two numbers.
For example – let’s calculate by what percent is 5 greater than 4:
6) Storing Numbers
The HP12C allows you to store numbers using the following key strokes:
Key in the value that you wish to store (unless the value is already displayed on the screen). We will use 1,234 in the example below. Key [STO] followed by the storage register (0 – 9) that you wish to store your value in:
To recall a stored value, press [RCL] followed by the register (0 – 9) where your value was stored:
Note: Hitting [f] REG will clear the storage registers. You may also overwrite a single stored register by storing a new value in the register.
7) Change Sign
To indicate a negative number, or change a negative number to a positive one, we use the [CHS] key:
8) Resetting to Factory Settings
If you wish to reset your HP12C to factory settings, you may do so by keying the following:
- Turn the calculator off.
- Hold the subtract button while simultaneously turning the calculator back on. The HP12C will display PR ERROR – this is normal.
- Release the subtract button and then turn the calculator off.
- Upon turning the calculator back on, the HP12C should now be reset to factory settings.
HP12C Examples: Using Key Financial Functions
A strength of the HP12C is its intuitiveness for completing TVM calculations.
The five keys in the top left corner (including their [f] and [g] functions) are all used for these types of problems.
1) Future Value of an Ordinary Annuity
Example: You open a savings account with an initial $775 deposit. The savings account will pay 2% compounded monthly. Beginning next month, you intend to make monthly deposits of $50 for the next five years. What will your deposit account be worth in five years?
First, press [CLx] followed by [f] FIN to clear the screen and financial registers.
Enter the annual interest rate, 2, followed by [g]12÷ to convert to the monthly rate and automatically store the value.
Enter the initial deposit: 775 [CHS] [PV]
Enter your monthly payments: 50 [CHS] [PMT]
Enter the number of years, 5, followed by [g] 12x to convert to monthly periods and automatically store the value
To calculate the future value of the savings account, hit [FV]. The HP12C will display 4,008.80:
Notes about the above example:
- You can input these values in any order – it’s irrelevant what order you enter the above inputs prior to calculating FV.
- If a TVM problem uses monthly compounding as was the case in the above example, the HP12C has keys which make the calculation more convenient:
- To calculate and store the number of periods with monthly compounding, key the number of years followed by [g] 12x.
- To calculate and store the interest rate with monthly compounding, key in the annual interest rate followed by [g] 12÷. Note that the HP12C automatically converts the interest rate to a decimal.
- If a problem uses annual compounding, all that is necessary is to key in the number of years or annual interest rate followed by [n] or [i], respectively.
2) Present Value of Uneven Cash Flows
Example: You will receive $150 in Year 1, $80 in Year 2, $90 in Year 3, $100 in Year 4 and $110 in Year 5. The required rate of return is 10%. The initial investment will be $400. What is the NPV of these cash flows?
First, press [CLx] followed by [f] FIN to clear the screen and financial registers.
Enter the initial investment, 400 [CHS] followed by [g] CF0:
Enter the yearly cash flows, followed by [g] CFj each time:
Enter the required rate of return, 10, followed by [i]
Enter [f] NPV which will display 6.70.
In the above example, if you wished to find the IRR, you would key [f] IRR instead of [f] NPV after entering all cash flows. Remember to use correct cash flow sign conventions be used (use opposing signs when cash is flowing in vs out), otherwise your answer will not make sense!
How To Use HP12C: General Tips & Advice
- Always ensure that you’ve correctly set your calculator to either beginning or end of period based on when cash flows occur. Beginning will be identified on the screen, end will not. To switch to beginning mode, use the following keystrokes [g] BEG
- If you accidentally key the [f] or [g] prefix, you may cancel it by pressing [CLx].
- Be aware, unless you’re using the Platinum edition HP12C, there is no Backspace key.
- It’s helpful to draw up a cash flow timeline when using your HP12C for Time Value of Money calculations.
- Once you have solved a TVM problem using the HP12C, as with any type of calculator or Excel, it’s helpful to perform a quick sanity check by giving the answer a second look to be certain it makes sense.
Hope these set of tips will get you to a flying start with your HP12C calculator. If you’d like to see more, let us know in the comments below!
Which HP12C calculator function did you find particularly useful? Do you have further tips to share? Let us know your comments below!
P.S. – Meanwhile, here are some related articles that you may find useful:
- Still unsure which calculator to choose? Check out our BA II Plus vs HP12C calculator guide →
- Decided on BA II Plus calculator? Remember to refer to our BA II Plus Calculator Guide for CFA, FRM and CAIA Exams →
Great article! Always pleased to see articles that show people the merits of RPN. It’s such an underappreciated input notation. I always tell the interns, if they are pressed for time for the exams, just get a TI. There is no time to learn RPN proficiently. Last thing you want is a candidate messing up a simple operation because of RPN. But if they are not going for an exam in the near future and are interested in calculators and doing calculations, RPN is well worth overcoming the initial barrier.
This thing is a dinosaur and should be killed. Other than RPN and some modest programmability it has less capability than the HP10Bii, and unlike the HP10 and HP17, it’s unintuitive. Likewise, its never been updated, and perplexingly, if you solve for n – the number of periods in time value of money calculations – it rounds upward, giving an incorrect answer. I am telling my students to toss it in the trash and buy the 10 or 17.
The calculator is used in a lot of professional exams. Unless those exam authorities change their calculator policy, the HP12C will continue its production. Personally, I love the form factor of the HP12C as it is so easy to hold in the hand, and the design is timeless. Although the build quality has declined over the years, it is still made to last, unlike the newer models of other brands. Although some of your points are justified, I am glad the HP12C is still alive and well.
You don’t need to use RPN as it is very confusing vs traditional calculators , If you have HP 12 C Platinum you can change RPN to ALG (algebra) after doing that it will start working like normal traditional calculator.
I own TI BA ii plus , TI BAII plus professional and have HP12C Platinum and chances of error are minimal in HP 12 C Platinum whereas chances of error in TI BAII Plus professional are very high , TI BA II Plus cheap version is good as button gives a feedback where as professional version is too rigid , also good thing about HP12C is that it has a backup batter ( not saying you should not have a backup in CFA exam).
If anyone will use HP12 C platinum he/she will not be disappointed whereas TI BA II plus professional will disappoint you a lot ( I mean a lot).
I agree that the effort to learn RPN may not be worthwhile to most people, but for those who are proficient in it, it is far easier and intuitive to use compared to the conventional way. “A+B=C” is easier for layman doing simple operations, but the power of thinking in terms of “SUM(A,B)” is apparent for long and complex calculations. (My gripe is that there are not enough stack registers for such calculations, which defeats the purpose of RPN. They really should double it from 4 to 8, or better yet, 16, for those need such insane complexity.) The whole reason I stick with HP is because of RPN.
What do you mean by chances of error? All these calculators are largely accurate for general purposes.
I agree that the build quality of HP calculators in general are much higher than TIs, though it has declined in recent decades. I have several of them, from my dad’s one to recent ones (I keep buying anniversary models), and the quality of the newer ones is noticeably worse.