Customer Acquisition Cost (CAC) Calculator

A transparent, offline tool for founders, growth teams, and finance professionals to calculate and understand the true cost of acquiring a customer. All calculations run instantly in your browser.

Estimates only. Verify with your own data.

Total Acquisition Spend (Period)

Sum of all marketing & sales costs for a period (ads, salaries, tools).

New Customers Acquired (Same Period)

Number of paying customers gained in that period.

Reporting Period

Scenario Adjustment

Adjusts spend for planning scenarios.

Decimal Places

CAC Result

Customer Acquisition Cost

$50.00

per customer (quarterly)

Adjusted Spend: $12,500.00

Customers Acquired: 250

Period: Quarter

Assumptions Used

Spend includes all marketing & sales costs.
Customer count is for new paying customers only.
No payback period or LTV calculated here.

Understanding Customer Acquisition Cost (CAC)

Why CAC Matters

CAC measures the total cost to acquire one paying customer. It's a fundamental growth and unit‑economics metric. A sustainable business model requires your Customer Lifetime Value (LTV) to be significantly higher than your CAC (common rule of thumb: LTV:CAC > 3:1). Tracking CAC helps you evaluate channel efficiency, set marketing budgets, and forecast profitability.

What Each Input Means

Input	What It Represents	Where to Find It
Total Acquisition Spend	All expenses directly tied to acquiring customers in a period: advertising costs, salaries of marketing/sales teams, software/tools, agency fees, content production, and events.	Marketing & Sales line items in your P&L; ad platform reports; payroll system.
New Customers Acquired	Count of net new paying customers who started paying within the same period. Excludes trials, leads, or free users.	Billing system (Stripe, Chargebee), CRM (HubSpot, Salesforce) with "closed‑won" status.
Reporting Period	The timeframe over which you're measuring spend and acquisitions. Consistency is critical for trend analysis.	Align with your financial reporting (monthly, quarterly).

Step‑by‑Step Guide

Gather all marketing and sales expenses for a chosen period (e.g., last quarter).
Count the number of new paying customers who started in that same period.
Enter both numbers into the calculator. Select the matching period.
Review the CAC result. Use the scenario selector to model "what‑if" planning.
Compare your CAC to your average revenue per customer and estimated LTV.

Realistic Examples

Example 1: SaaS Startup

Spend: $8,000 (monthly) on Google Ads + 1 marketer salary. New Customers: 40. CAC = $200. If average monthly subscription is $50, payback is 4 months.

Example 2: E‑commerce Brand

Spend: $45,000 (quarterly) on Instagram/Facebook ads. New Customers: 900. CAC = $50. If average order value is $75 with 40% gross margin, the first‑order profit is negative, requiring repeat purchases.

Common Mistakes Checklist

Including non‑acquisition costs (like R&D or customer support). Counting leads or trial users instead of paying customers. Mismatched time periods (e.g., monthly spend vs. quarterly customers). Forgetting to prorate annual contracts or one‑time setup fees.

Interpretation Guide

If your CAC is rising: Marketing channels may be饱和, competition increasing, or targeting too broad. Review channel‑level CAC.

If your CAC is very low: Ensure you're capturing all costs (especially salaries). Low CAC can indicate strong product‑market fit or untapped scale potential.

Before acting: Double‑check expense categorization, customer attribution window, and compare CAC to LTV (not just revenue).

Target CAC Solver

Determine the required spend or customers to hit a specific CAC target.

Target CAC

I Know My

Fixed Value

Frequently Asked Questions

What costs should I include in CAC?

Include all expenses directly tied to acquiring customers: advertising spend, salaries of marketing/sales teams, commissions, software (CRM, marketing automation), agency fees, and content production. Do not include overhead like office rent, product development, or customer support.

Should I use gross or net new customers?

For pure CAC, use gross new customers (customers who started paying in the period). For cohort‑based LTV:CAC analysis, you may want to offset churn, but that's a separate metric (Net CAC). This calculator uses gross for simplicity.

Monthly vs. annual CAC—which is better?

Consistency is key. Monthly CAC is more sensitive and useful for fast‑moving teams. Annual CAC smooths seasonal spikes. Choose one and stick with it for trend analysis. The calculator lets you select your period.

How accurate is this calculator?

It provides a straightforward mathematical estimate based on your inputs. Real‑world accuracy depends entirely on correctly categorizing expenses and attributing customers. Always cross‑check with your finance team.

When should I involve a finance specialist?

When making material budget decisions, setting long‑term growth targets, preparing investor reports, or if your expense allocation is complex (e.g., blended roles, capitalized software).

Formulas & Assumptions

Primary Formula

CAC = Total Acquisition Spend ÷ New Customers Acquired

Scenario Adjustment

Adjusted Spend = Input Spend × Scenario Multiplier (Conservative: ×1.2, Base: ×1.0, Aggressive: ×0.8).

Rounding

Results are rounded to the selected decimal places. Intermediate calculations use full precision.

Target Solver Logic

If solving for spend: Required Spend = Target CAC × Fixed Customer Count.
If solving for customers: Required Customers = Fixed Spend ÷ Target CAC.

For informational and educational purposes only. Estimates depend on your inputs and simplifying assumptions. This tool does not replace professional financial, accounting, or operational advice.

Sources: Basic business math for margins, pricing, and break‑even; General SaaS metrics definitions (MRR, churn, LTV, CAC).

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Customer Acquisition Cost CAC Calculator

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