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Formula Calculator

Formula calculator works out Result and Unrounded result from Expression, Arithmetic and Variables (optional). The default figures on this page give result of 38; change any entry and the result, the working and the sources update together.

Result

Basic Arithmetic Calculator

Unrounded result

Expression evaluated

2 * (l + w)

Result with separators

Result as a fraction

Operation

Expression

Arithmetic used

Binary floating point (IEEE-754 double)

Worked out from ISO 80000-2, Quantities and units — Part 2: Mathematics (operator symbols and precedence) and 3 other sources.

Your figures

Updates as you type

ExpressionUse + - * / ^ ( ) and % for remainder. Multiplication and division are done before addition and subtraction. In "words" mode, type the sum in plain English instead.

ArithmeticExact mode reads every decimal you type as a fraction and works in whole-number numerators and denominators. It cannot use pi, e or functions such as sqrt.

Variables (optional)Name a value the expression may use, e.g. "l = 12, w = 7" with an expression of 2 * (l + w).

Number displayChanges how the answer is written out. It never changes the arithmetic.

Working shown

Round result to (decimal places)

How this is worked out

3 steps

Evaluate 2 × (l + w) using standard operator precedence.
12 + 7 = 19 → 2 × 19
2 × 19 = 38 → 38

Step-by-step workingtable

12 + 7 = 19 → 2 × 19, 2 × 19 = 38 → 38

Its 12 worked examples are re-run on every release, last on 15 September 2026. What changed

Sources and references

4 sources

ISO 80000-2, Quantities and units — Part 2: Mathematics (operator symbols and precedence)

2019

NIST Digital Library of Mathematical Functions, §1.1 Notation

IEEE 754-2019, Standard for Floating-Point Arithmetic

2019 · Why 0.1 + 0.2 is not 0.3 in the default mode, and what exact mode avoids.

Unicode CLDR number formatting patterns (es-ES decimal comma, en-IN lakh/crore grouping)

What the formula calculator calculates

Adds, subtracts, multiplies, divides and exponentiates numbers, either as a free-form expression evaluated with correct operator precedence, as two named operands, as a list folded left to right, or as a sum written out in words — in binary floating point or in exact fraction arithmetic.

How to use this formula calculator

Enter Expression, Arithmetic, Variables (optional) and Number display. Result updates as you type. Change one figure at a time to see what drives the result.

How the result is worked out

Open “How this is worked out” beside the result for the step-by-step calculation behind Result, Unrounded result and Expression evaluated.

The method follows ISO 80000-2, Quantities and units — Part 2: Mathematics (operator symbols and precedence), NIST Digital Library of Mathematical Functions, §1.1 Notation, IEEE 754-2019, Standard for Floating-Point Arithmetic and Unicode CLDR number formatting patterns (es-ES decimal comma, en-IN lakh/crore grouping).

What you can compare

Change one input at a time to see how it affects Result, Unrounded result and Expression evaluated. The inputs you can vary are Expression, Arithmetic, Variables (optional), Number display and Working shown.

Results are general information, not financial, tax, legal, medical or engineering advice. Check any decision that matters with a qualified professional.

Embed this calculator on your website

Copy this code into any page. The calculator appears with the figures currently entered, sizes itself to fit, and a small credit line links back here. Free, no account, no ads inside it, no tracking of your readers. Set your own figures and fixed fields; Personal removes the credit line, sets your colour and shows you which sites use it.

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<script src="https://calculatorfox.org/assets/js/embed-host.js" async></script>

Preview

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Frequently asked questions

What information do I need for the formula calculator?

You need Expression, Arithmetic, Variables (optional), Number display and Working shown. The page opens with default figures that give result of 38, so you can see the scale before entering your own.

What does this formula calculator show?

It shows Result, Unrounded result, Expression evaluated, Result with separators, Result as a fraction, Whole-number quotient, Remainder and Operation, with the working and any warnings for your entries.

Can I check how the formula calculator result was calculated?

Yes. The “How this is worked out” section shows the calculation steps, and the sources section identifies the references used for the method.

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