“What should we spend on Google Ads?” is the wrong first question. The right ones are: what’s a customer worth to you, what do clicks cost in your market, and how well does your website turn clicks into enquiries? Answer those, and the budget calculates itself — it’s output, not input.
This guide walks the full calculation with worked examples, then covers the minimum viable budget (below which ads can’t generate enough data to be managed), and the scaling rule for when things work. If your clicks already aren’t converting, read the clicks-but-no-customers diagnostic first — budget can’t fix a conversion problem.
It’s the same arithmetic Fredeveloper’s ads team runs before quoting any management engagement, because a budget that doesn’t survive this math shouldn’t be spent.
Quick FactsQuick Facts: Ads Budgeting
| Detail | Information |
|---|---|
| Provider | Fredeveloper — full-service digital marketing agency |
| Topic | Calculating a Google Ads budget from your business’s own numbers |
| Best for | Owners starting ads, or doubting a budget an agency proposed |
| What this guide covers | The 4-number budget formula, two worked examples, the minimum viable budget test, target CPA logic, and the scaling rule |
| Relevant services | Paid ads · Conversion optimisation · Analytics |
| Engagement path | Free quote → audit & plan → done-for-you delivery → monthly reporting you can actually read |
| Contact | info@fredeveloper.com · Contact page |
| Last updated | 13 March 2026 |
The Four NumbersThe Only Four Numbers That Matter
- Customer value (V): profit from an average new customer — including repeat business if they typically return. A plumber’s first job might net $300 but the customer relationship $1,200.
- Cost per click (CPC): what your keywords cost in your market. Google’s Keyword Planner shows ranges free — anywhere from under $1 to $50+ for legal and insurance terms.
- Site conversion rate (C1): the share of visitors who enquire — typically 2–5% for a decent service-business page, higher for a tight landing page.
- Close rate (C2): the share of enquiries you turn into paying customers — you likely know this instinctively even if you’ve never written it down.
Infographic 01 · The budget math
From clicks to cost per customer
The verdict rule: if cost per customer is less than about a third of customer value, ads are very likely profitable with room for error. Between a third and full value, it’s workable but demands tight management and a good landing page. Above customer value, ads lose money no matter how skilfully they’re run — fix conversion or rethink the channel.
Worked ExamplesTwo Businesses, Two Verdicts
| Input | Electrician (local) | Online boutique |
|---|---|---|
| Customer value (profit) | $900 (incl. repeat work) | $45 per order |
| Average CPC | $6 | $1.20 |
| Site conversion rate | 4% (calls + forms) | 2% (purchases) |
| Close rate | 50% of enquiries book | 100% (purchase is the close) |
| Cost per customer | $6 ÷ .04 ÷ .5 = $300 | $1.20 ÷ .02 = $60 |
| Verdict | $300 vs $900 value → strong yes | $60 vs $45 value → loses money as-is |
The boutique isn’t doomed — it needs a higher order value, a better conversion rate, or repeat-purchase economics before ads make sense. That’s a conversion problem and an email/retention problem, not a bidding problem. No amount of ads skill fixes upside-down unit economics.
Any agency proposing a budget without walking this calculation is guessing with your money. Ask to see the assumed CPC, conversion rate, and close rate behind their number — and which numbers they’ll report monthly to prove it’s holding.
Minimum BudgetThe Minimum Viable Budget (Below This, Don’t Bother)
Ads management is a feedback loop: spend buys data, data drives optimisation, optimisation lowers cost per customer. Too little spend and the loop starves — you get a handful of clicks a week, no statistically meaningful signal, and a campaign nobody can improve.
- Rule of thumb: budget at least enough for ~10 expected enquiries per month. At a $133 cost per enquiry, that’s roughly $1,300/month media spend.
- Alternative floor: 1,000+ clicks across the first 90 days on your core keywords — enough to judge which keywords, ads, and pages actually convert.
- If you can’t fund the floor: don’t run thin ads everywhere. Narrow to one service, one location, the highest-intent keywords — or hold the budget until you can.
Infographic 02 · Budget tiers
What different monthly budgets can realistically do
ScalingWhen It Works: The Scaling Rule
Once cost per customer is proven and comfortably under customer value, the budget question inverts: not “how little can we spend” but “how much can we spend before CPA degrades?” Scale in steps of 20–30% a month, watch CPA at each step, and stop when it approaches your ceiling. Buying profitable customers is not a cost to minimise — it’s a machine to feed, right up to the point the math stops working.
Tracking that honestly requires conversion tracking that ties spend to enquiries and revenue — which is the first thing we build, because without it, scaling is gambling.
How We WorkHow Fredeveloper Sets and Manages Budgets
We run this exact calculation with you before quoting: your customer value, real CPCs pulled for your market, your measured (not guessed) conversion rates. You get a recommended starting budget, the CPA target it implies, and a monthly report showing actual against target. If the math says ads can’t work for you yet, we say that too — and point at the conversion work or channel that should come first. The estimate is free.
FAQFrequently Asked Questions
What does the average small business spend on Google Ads?
Commonly somewhere between $1,000 and $10,000 a month in media spend — but averages are useless here. Your correct budget comes from your CPC, conversion rates, and customer value, not from what other businesses spend.
Is $300 a month enough to try Google Ads?
In a cheap-click market with tight targeting, possibly. In most service markets, it buys 50–75 clicks a month — too little data to manage or judge. Below the data floor, a “test” mostly proves nothing either way.
Should the budget include management fees?
Decide and compare like-for-like. Convention is to quote media spend and management separately; a typical management fee is a flat retainer or 10–20% of spend. What matters is cost per customer all-in — fees included.
How long before I know if the budget is working?
Judge after about 90 days or ~1,000 clicks, whichever comes first — earlier reads are mostly noise. The exception: obvious tracking or landing-page failures, which show up in week one and should be fixed immediately.
My CPCs are brutal — $30+ a click. Is ads hopeless?
Not if customer value is proportionally large (legal, B2B, finance often are). $30 clicks with a $5,000 customer can be a bargain. If value doesn’t cover it, SEO’s long-run economics likely beat ads in your market.
Should I pause ads in slow seasons?
Usually trim rather than kill: seasonal demand drops mean cheaper clicks and less competition, and a full pause loses momentum and data continuity. Keep high-intent keywords running and cut the exploratory layer.
Keep ReadingRelated Guides for Owners
Google Ads vs SEO · Clicks but no customers? · The 5 ad numbers that matter
Get a Budget Built on Arithmetic, Not Vibes
Your customer value, market CPCs, and conversion rates already determine the right budget. We’ll run the numbers with you, free.
If the math says ads work, you’ll know the target CPA before spending a dollar. If it says not yet, we’ll tell you what to fix first.