Convert octal to decimal

Converts any number of octal to decimal with our online calculator. To do this, enter the number whose equivalence you want to know in decimal format and press the calculate button.

If you wish, we also have at your disposal a decimal to octal converter.

How to convert from octal to decimal

The octal system is called octal because it works in base 8 and has a total of eight symbols ranging from 0 to 7.

If we want to convert from octal to decimal, we must take into account the above to understand the process, although you will see that it is very easy.

For convert from octal to decimal you simply have to take the octal number from right to left and assign to each one the power in base eight that corresponds to it, being the first of all 80.

Powers can be easily calculated with our exponents calculator.The sum of all the terms will give you the result of the decimal number you are looking for. The sum of all the terms will give you the decimal number you are looking for.

If you are not very clear about how to convert from octal to decimal Based on this explanation, here are some practical examples that will help you understand it much better.

Examples of octal to decimal

Octal to decimal converter

Here are some examples that will help you to understand the calculations required for convert from octal to decimal:

Example 1: converting 37 from octal to decimal

378 = 3×81+7×80 = 24+7 = 31

Example 2: converting 7014 from octal decimal

70148 = 7×83+0×82+1×81+4×80= 3584+0+8+4 = 3596

If you have any questions, our octal to decimal calculator also shows you the calculations needed to arrive at the corresponding decimal number.

Conversion from octal to decimal with Excel

If you prefer to make your own calculator to convert from octal to decimal, you can go to Excel to get it. Microsoft's program incorporates a function to obtain the equivalence although it has some limitations.

For example, Excel is not able to convert a number that has more than 10 octal characters (30 bits). Of those 30 bits, the most significant is the sign bit while the remaining 29 are magnitude bits.

To make the octal to decimal conversion using Excel, we simply have to type the following formula in an empty cell:


In parentheses we can write the number octal or refer to another cell in which that number is written.

For example, if we want to convert octal number to decimal 3456, we write the formula in this form:


And Excel returns that the equivalent decimal number is 1838.

Octal to decimal equivalence table

Below you will find a table of equivalence of octal to decimal in which you can clearly see some of the concepts that we have seen in the previous points.

As you can see, the correspondence between octal and decimal up to the number 7 is the same. However, as the octal system has only 8 symbols (from 0 to 7), when exceeding seven we have to resort to using two symbols.


Octal to Decimal Calculator

Octal to decimal calculator

If you work with number systems such as octal, you probably have a scientific calculator in your possession. If it's relatively new, you can probably use it for convert from octal to decimal.

We will use a Casio scientific calculator to explain how the conversion is done step by step:

  1. Lo primero de todo es localizar la tecla que pone "MODE SETUP" ó "MENU CONFIG" en su parte superior. Lo habitual es que se encuentre en la parte superior derecha.
  2. Tras pulsarla, entrarás en el menú de la calculadora y saldrán varias opciones por la pantalla. Tienes que seleccionar la opción que pone "Base-N"
  3. A continuación le tenemos que decir a la calculadora que vamos a escribir un número en sistema octal. Para ello, pulsaremos la tecla que en tiene en su parte superior las letras "OCT". En la calculadora de la foto puedes ver dicha tecla en la última fila de botones.
  4. Type the octal number you want to convert to decimal
  5. Press the equal key (=).
  6. To make the conversion to octal to decimal, pulsa la tecla que tiene un "DEC" escrito en la parte superior. Dicha tecla se encuentra en la misma fila que el botón del paso 3.

If you've done it right, you'll have gone from octal to decimal with the calculator.

12 thoughts on “Pasar octal a decimal”

    • Hello William,

      If you want to convert from octal to decimal the number you are talking about, you only have to follow the process described in the web.


      43,25(8) = 4×81 + 3×80 + 2×8-1 + 5×8-2

      And what you get from that sum will be the fractional octal number converted to decimal.


    • Thanks for your comment Bated, if you need help to make the change from octal to decimal or any other numeric system let us know.


    • Hi Daniel, just that question was asked by William so we answered it a few comments above. If you still don't know how to pass that octal number with comma to decimal, tell us where you got stuck and we will help you.

    • Hello "Laura García Baidez" to convert the number 156 to decimal you must do the following:

      You must multiply each digit of the octal number by 8 and power it by the corresponding number. To know which is the corresponding number you have to do this: if the octal number has 3 digits you are going to start boosting by 2, then by 1 and then by 0 and so on, another example is that if an octal number has for example 5 digits you have to start boosting from a number less than the amount of digits that the number has, in this case the number less than 5 in an orderly way is 4 and from there you go down until you always reach 0.

      156= 1×8^2 + 5×8^1 + 6×8^0= 110

    • Hola Dayana, sólo tienes que introducir esas cifras en nuestro conversor y automáticamente obtendrás la equivalencia de octal a decimal.

      Si lo que quieres es el paso a paso, en el texto te explicamos cómo hacerlo. Cualquier duda o si te atascas en algún paso nos dices.

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