Octal to Decimal Converter 2026-27 — GlobalCalc

GlobalCalc

Inputs

Number

Results update as you type

Results

Converted

173

Decimal value—

Binary—

Octal—

Hexadecimal—

Bits needed—

Reviewed September 2026. Pure mathematics: the result does not depend on where you are. Terminology follows the national curriculum (maths, brackets, decimal point).

All calculations run 100% in your browser. The calculator code does not submit your figures to GlobalCalc to obtain a result.

About octal to decimal converter

Method

How the octal to decimal converter works

Multiply each digit by its place value and add: the places are 1, 8, 64, 512 and so on. 377 is 3×64 + 7×8 + 7 = 255.

It is the same positional arithmetic as decimal, with eight in place of ten.

Formula: value = Σ digitₖ × bᵏ

Data

Worked examples

Inputs	Converted	Note
377	255	255
755	493	493
10	8	8

FAQ

Frequently asked questions

How do I convert octal to decimal?

Multiply each digit by its power of eight and add them up.

What is 377 in decimal?

255.

What are the octal place values?

1, 8, 64, 512, 4096 — successive powers of eight.

Can octal contain an 8?

No. Octal digits run 0 to 7 only; an 8 or 9 means the number is not octal.

What is chmod 755 as a decimal?

493, though nobody uses it that way — the octal digits are the point.

Sources

Where these figures come from

NIST Digital Library of Mathematical Functions — reference definitions for elementary and special functions
Wolfram MathWorld — definitions and formulas for every topic on this page
NIST/SEMATECH e-Handbook of Statistical Methods — the statistical formulas (mean, variance, z, confidence intervals, sample size)
National curriculum in England — Mathematics — the terms and methods taught in UK schools

Last checked: September 2026. Formulas are fixed by mathematics and do not change with tax years or regulations.