Numbers Math Money Snippets

Custom Code Snippets — Numbers, Math & Money

Copy-paste examples for arithmetic, rounding, currency formatting, percentages, and other numeric tasks inside a Custom Code workflow step. Reach for the Num helper for rounding, formatting, and clamping; standard Math is also available for trig / logs / square roots.

The Num helper covers round, floor, ceil, abs, min, max, random, randomInt, and format.

Compute a line total with tax

// Inputs: price (record_val), qty (record_val), tax_rate (custom_val 0.0875)
const price = Number(params["price"]) || 0;
const qty   = Number(params["qty"])   || 0;
const rate  = Number(params["tax_rate"]) || 0;

const subtotal = price * qty;
const total    = Num.round(subtotal * (1 + rate), 2);

returnData("subtotal", subtotal);
returnData("tax",      Num.round(subtotal * rate, 2));
returnData("total",    total);

Format currency for display

// 1234.5 -> "$1,234.50"
const amount    = Number(record.amount) || 0;
const formatted = `$${Num.format(amount, 2)}`;
returnData("amount_display", formatted);

Display amounts in any currency

// Inputs: amount (record_val), currency (custom_val "USD"/"EUR"/"GBP"/"ILS")
const amount   = Number(params["amount"]) || 0;
const currency = (params["currency"] || "USD").toUpperCase();

const symbols = { USD: "$", EUR: "€", GBP: "£", ILS: "₪", CAD: "$", AUD: "$" };
const symbol  = symbols[currency] || "";

returnData("display", `${symbol}${Num.format(amount, 2)} ${currency}`);

Clamp a value between min and max

const score = Number(params["score"]) || 0;
returnData("score_clamped", Num.min(100, Num.max(0, score)));

Percent change between two numbers

// Inputs: previous, current
const prev = Number(params["previous"]) || 0;
const curr = Number(params["current"])  || 0;

const change = prev === 0 ? null : Num.round(((curr - prev) / prev) * 100, 2);

returnData("pct_change", change);
returnData("trend", change == null
  ? "n/a"
  : change > 0 ? "up" : change < 0 ? "down" : "flat");

Convert cents to dollars (Stripe-style)

const cents = Number(params["amount_cents"]) || 0;
returnData("dollars", Num.round(cents / 100, 2));

Convert dollars to cents (for Stripe API calls)

// Stripe wants integer cents — never floats
const dollars = Number(params["amount"]) || 0;
returnData("amount_cents", Math.round(dollars * 100));

Calculate tip and split among diners

// Inputs: subtotal, tip_pct (e.g. 0.18), party_size
const subtotal  = Number(params["subtotal"]) || 0;
const tipPct    = Number(params["tip_pct"])  || 0.18;
const partySize = Math.max(1, Number(params["party_size"]) || 1);

const tip   = Num.round(subtotal * tipPct, 2);
const total = Num.round(subtotal + tip, 2);
const each  = Num.round(total / partySize, 2);

returnData("tip", tip);
returnData("total", total);
returnData("per_person", each);

Apply a percentage or flat-amount discount

// Inputs: subtotal, discount_type ("pct" or "flat"), discount_value
const subtotal = Number(params["subtotal"]) || 0;
const type     = params["discount_type"] || "pct";
const value    = Number(params["discount_value"]) || 0;

let discount;
if (type === "pct")  discount = subtotal * (value / 100);
else                 discount = value;

discount = Math.min(subtotal, Math.max(0, discount));   // never negative, never bigger than subtotal
const total = Num.round(subtotal - discount, 2);

returnData("discount", Num.round(discount, 2));
returnData("total",    total);

Weighted average of grades

// Inputs: grades (array of {score, weight})
const grades = Array.isArray(params["grades"]) ? params["grades"] : [];

let sum = 0, weight = 0;
for (const g of grades) {
  const s = Number(g.score)  || 0;
  const w = Number(g.weight) || 0;
  sum    += s * w;
  weight += w;
}

const avg = weight === 0 ? null : Num.round(sum / weight, 2);
returnData("weighted_average", avg);

Compound interest over N years

// Inputs: principal, rate (0.05 for 5%), years, periods_per_year (12 = monthly)
const p = Number(params["principal"]) || 0;
const r = Number(params["rate"])      || 0;
const t = Number(params["years"])     || 0;
const n = Number(params["periods_per_year"]) || 12;

const amount = p * Math.pow(1 + r / n, n * t);
returnData("future_value", Num.round(amount, 2));
returnData("interest_earned", Num.round(amount - p, 2));

Convert between currencies

// Inputs: amount_usd, eur_per_usd (e.g. 0.92)
const usd  = Number(params["amount_usd"])  || 0;
const rate = Number(params["eur_per_usd"]) || 0;

returnData("eur", Num.round(usd * rate, 2));

Progress percentage with safe divide

// Inputs: completed, total
const done  = Number(params["completed"]) || 0;
const total = Number(params["total"])     || 0;

const pct = total === 0 ? 0 : Num.round((done / total) * 100, 1);
returnData("pct_complete", pct);
returnData("status", pct >= 100 ? "done" : pct === 0 ? "not_started" : "in_progress");

Distance between two lat/lng points (miles)

// Inputs: lat1, lng1, lat2, lng2
function toRad(d) { return d * Math.PI / 180; }

const lat1 = Number(params["lat1"]) || 0;
const lng1 = Number(params["lng1"]) || 0;
const lat2 = Number(params["lat2"]) || 0;
const lng2 = Number(params["lng2"]) || 0;

const R    = 3958.8;   // Earth radius in miles
const dLat = toRad(lat2 - lat1);
const dLng = toRad(lng2 - lng1);
const a    = Math.sin(dLat / 2) ** 2 +
             Math.cos(toRad(lat1)) * Math.cos(toRad(lat2)) *
             Math.sin(dLng / 2) ** 2;
const c    = 2 * Math.atan2(Math.sqrt(a), Math.sqrt(1 - a));

returnData("miles", Num.round(R * c, 2));

Round to the nearest 0.05 / 0.25 / 5 / 100

// "Bankers" snap-to-step rounding
const value = Number(params["value"]) || 0;
const step  = Number(params["step"])  || 0.05;

const rounded = Math.round(value / step) * step;
returnData("rounded", Num.round(rounded, 2));