--- title: "Calculate action for ActionClip" canonical_url: "https://actionclip.app/actions/calculate" document_type: "standalone_action" official: true action_count: 1 catalog_schema_version: 1 catalog_revision: "2026-08-21.1" catalog_published_at: "2026-08-20T18:50:00Z" --- # Calculate action for ActionClip Evaluate a selected mathematical expression locally. ## What it does Uses a purpose-built parser rather than eval. Supports arithmetic, parentheses, right-associative powers, implicit multiplication, percentages, constants, and common functions, with finite results rounded to 14 significant digits. A trailing equals sign appends the result. ## Action details | Field | Value | | --- | --- | | Category | Conversions & Utilities | | Action type | JavaScript | | Result | Replace or copy text | | Internet | Not required | ## Action and outcome | Action | Outcome | | --- | --- | | **Calculate** — Selected text: 100 / 4 = | 100 / 4 =25 | ## How to evaluate a selected mathematical expression locally with ActionClip 1. Select the text you want to use. 2. Choose **Calculate** from ActionClip. 3. Review the result, then replace the selection or copy the new text. ## Requirements No setup required. ## Privacy Runs locally in ActionClip’s JavaScript sandbox. Selected text does not leave your Mac. ## Action configuration ````javascript function run(selected_text) { const original = selected_text.trim(); if (!original) throw new Error("Enter a mathematical expression."); if (original.length > 1000) throw new Error("Expressions are limited to 1,000 characters."); const appendsResult = /=\s*$/.test(original); let expression = appendsResult ? original.replace(/=\s*$/, "").trim() : original; if (!expression) throw new Error("Enter an expression before the equals sign."); // Decimal commas are accepted for arithmetic-only input. Function argument // commas remain separators, so min(1, 2) is never rewritten as a decimal. if (!/[A-Za-z_]/.test(expression) && !expression.includes(".") && /\d,\d/.test(expression)) { expression = expression.replace(/(\d),(?=\d)/g, "$1."); } const tokens = []; let index = 0; while (index < expression.length) { const character = expression[index]; if (/\s/.test(character)) { index += 1; continue; } if (/\d/.test(character) || (character === "." && /\d/.test(expression[index + 1] || ""))) { const start = index; let sawDot = false; if (character === ".") { sawDot = true; index += 1; } while (/\d/.test(expression[index] || "")) index += 1; if (!sawDot && expression[index] === ".") { sawDot = true; index += 1; while (/\d/.test(expression[index] || "")) index += 1; } if (/[eE]/.test(expression[index] || "")) { const exponentStart = index; index += 1; if (/[+-]/.test(expression[index] || "")) index += 1; const digitsStart = index; while (/\d/.test(expression[index] || "")) index += 1; if (digitsStart === index) { throw new Error("Invalid exponent near position " + (exponentStart + 1) + "."); } } const rawNumber = expression.slice(start, index); const numeric = Number(rawNumber); if (!Number.isFinite(numeric)) throw new Error("Invalid number: " + rawNumber + "."); tokens.push({ type: "number", value: numeric }); continue; } if (/[A-Za-z_]/.test(character)) { const start = index; index += 1; while (/[A-Za-z0-9_]/.test(expression[index] || "")) index += 1; tokens.push({ type: "identifier", value: expression.slice(start, index).toLowerCase() }); continue; } if ("+-*/^(),%".includes(character)) { tokens.push({ type: character, value: character }); index += 1; continue; } throw new Error("Unsupported character “" + character + "” at position " + (index + 1) + "."); } tokens.push({ type: "end", value: "" }); let position = 0; const current = () => tokens[position]; const match = (type) => { if (current().type !== type) return false; position += 1; return true; }; const expect = (type, label) => { if (!match(type)) throw new Error("Expected " + label + "."); }; const finite = (value) => { if (!Number.isFinite(value)) throw new Error("The result is not a finite number."); return value; }; const constants = { pi: Math.PI, e: Math.E, tau: Math.PI * 2 }; const functions = { sqrt: (values) => values.length === 1 ? Math.sqrt(values[0]) : NaN, abs: (values) => values.length === 1 ? Math.abs(values[0]) : NaN, sin: (values) => values.length === 1 ? Math.sin(values[0]) : NaN, cos: (values) => values.length === 1 ? Math.cos(values[0]) : NaN, tan: (values) => values.length === 1 ? Math.tan(values[0]) : NaN, asin: (values) => values.length === 1 ? Math.asin(values[0]) : NaN, acos: (values) => values.length === 1 ? Math.acos(values[0]) : NaN, atan: (values) => values.length === 1 ? Math.atan(values[0]) : NaN, ln: (values) => values.length === 1 ? Math.log(values[0]) : NaN, log: (values) => values.length === 1 ? Math.log(values[0]) : NaN, log10: (values) => values.length === 1 ? Math.log(values[0]) / Math.LN10 : NaN, exp: (values) => values.length === 1 ? Math.exp(values[0]) : NaN, floor: (values) => values.length === 1 ? Math.floor(values[0]) : NaN, ceil: (values) => values.length === 1 ? Math.ceil(values[0]) : NaN, round: (values) => { if (values.length === 1) return Math.round(values[0]); if (values.length !== 2 || !Number.isInteger(values[1]) || Math.abs(values[1]) > 12) return NaN; const scale = Math.pow(10, values[1]); return Math.round((values[0] + Number.EPSILON) * scale) / scale; }, min: (values) => values.length ? Math.min(...values) : NaN, max: (values) => values.length ? Math.max(...values) : NaN, pow: (values) => values.length === 2 ? Math.pow(values[0], values[1]) : NaN, mod: (values) => values.length === 2 ? values[0] % values[1] : NaN }; let parseExpression; let parseUnary; const parsePrimary = () => { if (current().type === "number") { const value = current().value; position += 1; return value; } if (current().type === "identifier") { const name = current().value; position += 1; if (match("(")) { const values = []; if (!match(")")) { do { values.push(parseExpression()); } while (match(",")); expect(")", "a closing parenthesis"); } const callable = functions[name]; if (!callable) throw new Error("Unknown function: " + name + "."); return finite(callable(values)); } if (Object.prototype.hasOwnProperty.call(constants, name)) return constants[name]; throw new Error("Unknown constant: " + name + "."); } if (match("(")) { const value = parseExpression(); expect(")", "a closing parenthesis"); return value; } throw new Error("Expected a number, constant, function, or opening parenthesis."); }; const parsePostfix = () => { let value = parsePrimary(); while (match("%")) value /= 100; return value; }; const parsePower = () => { const left = parsePostfix(); if (match("^")) return finite(Math.pow(left, parseUnary())); return left; }; parseUnary = () => { if (match("+")) return parseUnary(); if (match("-")) return -parseUnary(); return parsePower(); }; const startsImplicitFactor = () => ["number", "identifier", "("].includes(current().type); const parseProduct = () => { let value = parseUnary(); while (true) { if (match("*")) value = finite(value * parseUnary()); else if (match("/")) { const divisor = parseUnary(); if (divisor === 0) throw new Error("Division by zero is not supported."); value = finite(value / divisor); } else if (startsImplicitFactor()) { value = finite(value * parseUnary()); } else break; } return value; }; parseExpression = () => { let value = parseProduct(); while (true) { if (match("+")) value = finite(value + parseProduct()); else if (match("-")) value = finite(value - parseProduct()); else break; } return value; }; const result = finite(parseExpression()); if (current().type !== "end") { throw new Error("Unexpected token “" + current().value + "”."); } const rounded = Number(result.toPrecision(14)); const formatted = Object.is(rounded, -0) ? "0" : String(rounded); return appendsResult ? original + formatted : formatted; } ```` ## Links - [HTML listing](https://actionclip.app/actions/calculate) - [Download action definition](https://actionclip.app/actions/calculate.actionclip) - [Browse Conversions & Utilities actions](https://actionclip.app/marketplace#marketplace-conversions) - [All Marketplace listings](https://actionclip.app/marketplace)