HP 35S Review – Is This Scientific Calculator Worth It?

There are plenty of brands of scientific calculator that are present in the market. Some are programmable and some can plot graphs like a graphing calculator. With this reason, finding the right option that suits your needs seems to be an overwhelming task. Right now, it seems like you heard about HP 35S and you try to figure out if this scientific calculator is worth it. So, I decided to come up with this HP 35S review in order to share my opinion and thoughts about this device.


Product Overview

  • Product: HP 35S Scientific Calculator
  • Price: $59
  • Cheapest Place to Buy: Amazon.com
  • My Rating: 9.6 out of 10

Product Overview

Hewlett-Packard (HP) 35S is one of the most flexible scientific calculator. Unlike other brands, you can choose between RPN or Algebraic system. It offers a large screen that displays the numbers and symbols clearly. If you prefer a device that can provide plenty of programmable scientific functions, this can be a good option.

HP 35S Review

This model is the latest version after HP 33s and aims to provide a better appearance and quality. It is slimmer compared to the old models but is wider and longer. It also offers a modern and more professional looking appearance. The only power source that you can use is battery and it doesn't have a solar option.

Like any other scientific calculator, you can use this device on various engineering and math related courses.

Functions & Operations

Built-in Conversions

On other brands, you have to look at the conversion table at the back of the calculator cover but in HP 35s there are built-in conversions that are readily available.

Some of these are Fahrenheit to Celsius, miles to km, pounds to kg and so many more. You can also use the ENG⇒ function to change the exponent of your digits by three every time you press it. For example, 1.399 x 10^-3 can be interpreted as 1,399 x 10^-6 once you press the key.

Stores More Intermediate Values

Typical calculator can store at least one memory but HP 35s can store 26 named memories. One good thing about this is that it can be retained on your calculator even if you turn it off. In order to store a value, first press blue-shift STO, then press the key of your desired letter. To retrieve the value, just use RCL and the letter that you have chosen.

By the way, all memories that you input can hold single real number, complex number or vector of real numbers.

Solve for Unknown Values

HP 35s has functions that can solve an equation to find an unknown variable. If there are more than one variable to be solved, you can define the variable that you want to find. If you are not fond of writing programs, this is helpful when you are dealing with complicated equations with more than one variable missing.

Reverse Polar Notation (RPN) System

Most calculators uses the standard algebraic notation. However, HP 35s is unique in the sense that it uses Reverse Polar Notation (RPN) system. To give you an overview, here is the major difference between the two systems.

Standard Algebraic Notation

In standard method, you should input the first digit, followed by the operation (add, subtract, multiply, divide) then the second digit and hit the ENTER key. This will give the answer. For example, " 2 + 2 ENTER " will generate the answer which is 4.

Reverse Polar Notation

In the RPN method, input the first digit, followed by ENTER then the second digit and hit the operation key. This will give your desired result. For example, you should press " 2 ENTER 2 + " in order to get the answer.

I must say that this is different from the usual calculator so it may take some time before you learn its process. But it can be a great help when you are dealing with complex operations. You don't need to input parentheses that somehow makes the equations on the screen confusing. Aside from that, you can also revise the equations that you previously inputted.

Fast and Accurate

It may be confusing at first but if you learn the process, RPN system can save you some time when solving problems.

Let me show an example by solving 2*(3+1):

RPN : 3 enter 1 +, 3, x (This gives 6 strokes)

Algebraic : 2 + 2 =, x 3 = (This gives 7 strokes)

It may not be too much but if you solve plenty of equations, this saved strokes will give you more time.

HP 35s also allows you to input complex expressions without using any parenthesis or brackets. You just have to simply perform the calculation in the order that is needed. And you don't have to press the enter key every time you want the operation to occur.

Aside from that, it also prevents mistakes from happening when you forgot or added more parenthesis in your equation. You can also easily evaluate expressions because of the automatic storage of results that you have input earlier.

Programming Calculator

The downside of HP 35s is that it can't act as a graphing calculator. However, you can fill up this weakness by taking advantage of its programming ability. This function is helpful when you encounter problems that require the same sequence of solution.

This means that it can execute repetitive operations, come up a decision and perform calculations that are needed to answer the problem. You just have to program it in your calculator.

There are also 30,000 bytes of program memory that is more than enough to provide you the needed program steps. It can hold more than one program at a time. And you can assign it to a single letter key and perform it by inputting XEQ "LETTER KEY" ENTER.

Personally, I am not quite familiar with the programming function because I am used to using the Casio fx-115ES PLUS. It uses the traditional algebraic system so I can't share that much information about the programming section.

However, if you are interested with programming, you can use its user manual that can guide you throughout the process.

Good Option for People Who are Willing to Learn

HP 35s is definitely one of those scientific calculator that offers top-notch functionality and good aesthetic appearance. Since it is a programmable, you can definitely use it just like any other ordinary calculator but can deal with complex equation and do repetitive tasks without any additional work.

On the other hand, I must say that learning the RPN system is not that easy most especially if you are already used to the algebraic system. However, once you get used to it, it will surely make you faster and more efficient when solving complex problems. Honestly, I am still having a hard time in mastering the RPN process but I also know some people who are benefiting from it. So it is just a matter of personal preference.

Nevertheless, the main goal in here is to give you a better option when choosing the scientific calculator that you can use on your test and exams.

If you have more questions and concerns, please comment down on the comment box below. Also, please let me know if you have hacks, tips or personal experience that you want to share about the HP 35s calculator.

John Rico

John Rico is an Engineer-in-Training Professional that works his way up to become a Licensed Professional Engineer.

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