Most small business owners spend too little on Google Ads to see any results. Others blow their budget in the first week and give up. Neither approach works.
The good news: there’s a logical way to set a Google Ads budget based on your actual business goals, not guesswork. Here’s how we do it with our clients at Phoenix Marketing.
Start With What a Customer Is Worth to You
Before you pick a number, you need to know what a new customer is actually worth to your business.
Let’s say you run a plumbing business. An average job is worth $400. If one in five leads turns into a job, you need five leads to win one customer. Now ask: how much are you willing to pay for a single lead? For a $400 job, $50-$80 per lead is perfectly reasonable. For a $10,000 kitchen renovation, you could justify spending $300 or more per lead.
This number, your maximum cost per lead (CPL), is the foundation of your entire Google Ads budget. Get this wrong and no amount of campaign optimisation will save you.
Work Backwards From Your Goals
Once you know your target CPL, the maths is straightforward.
If you want 20 leads per month and your target CPL is $60, you need a budget of $1,200/month. That’s your starting point. It won’t be perfect on day one, because Google Ads needs time to optimise. What it gives you is a rational baseline instead of a number picked out of thin air.
Too many businesses set their budget based on what they feel comfortable spending, then judge the campaign against results it was never funded to achieve. Set the budget based on the outcome you want, not what feels safe.
Why $300/Month Usually Doesn’t Work
We regularly speak to business owners who’ve “tried Google Ads” with $10 a day, seen little return, and written it off. The problem usually isn’t Google Ads. It’s the budget.
In most competitive Australian metro markets, trades, legal, finance, health, clicks cost between $5 and $20 each. At $10/day, you might get one or two clicks before your budget runs out by 9am. That’s not enough data to make decisions, and it’s certainly not enough volume to generate consistent leads.
There’s also a technical reason small budgets fail. Google’s Smart Bidding algorithm needs at least 30-50 conversions per month to optimise effectively. With a tiny budget, your campaign never exits the learning phase. You’re essentially paying Google to figure things out, without giving it enough runway to do so.
If $300/month is genuinely all you have, SEO or organic social may be a better use of those dollars. Come back to Google Ads once you can scale up.
What a Realistic Budget Looks Like in 2026
Here’s a rough benchmark for small businesses, broken down by industry. Industry benchmarks vary significantly, these are starting points, and your market, competition level, and conversion rate all affect what you’ll pay.
- Trades (plumbing, electrical, HVAC): $1,500-$3,000/month
- Legal and professional services: $2,500-$5,000/month
- Healthcare and allied health: $1,000-$2,500/month
- eCommerce: Start at 10-15% of your monthly revenue target from ads
- Local retail and hospitality: $500-$1,500/month
If your industry isn’t listed, think about the average click cost in your category and how many clicks you’d realistically need to generate one lead. That will get you to a workable number quickly.
Budget Alone Won’t Save a Poorly Built Campaign
Here’s the part most budget guides leave out: more money won’t fix a campaign that’s set up wrong.
We’ve audited accounts where businesses were spending $5,000/month on Google Ads and getting almost nothing back. Their keywords were too broad, their landing pages were slow and unconvincing, or their conversion tracking was broken. Google was spending the budget, alright. Just not on the right people. Weak creative does the same thing on Meta, which we cover in our guide to the ad creative formula.
Before you increase your spend, make sure these fundamentals are in place:
- Keyword targeting: Specific, intent-driven searches, not generic terms that attract browsers instead of buyers
- Landing page quality: Fast, mobile-friendly, with a clear headline and a single call to action
- Conversion tracking: Google needs to know what a “win” looks like, phone call, form submission, purchase
- Negative keywords: Filter out irrelevant searches so your budget isn’t wasted on people who’ll never buy
Get those foundations right first. Then scale the budget.
How to Know If Your Budget Is Working
Once your campaign is running, review these metrics monthly to judge whether your budget is being put to good use. Our post on real-time reporting and trend analysis covers what to look for.
- Cost per lead (CPL): What you’re paying for each enquiry. Compare this directly to your target CPL and adjust accordingly.
- Conversion rate: How many clicks turn into leads. Under 2% usually means the landing page needs work, not the ads.
- Impression share: The percentage of relevant searches where your ad appeared. If this is consistently below 40%, you may need a higher budget or tighter targeting.
- Return on ad spend (ROAS): For eCommerce, every $1 spent, how much comes back in revenue? Most businesses need a ROAS of at least 3x to be profitable after margins.
If your CPL is within range and leads are converting into paying customers, that’s your signal to scale. If not, fix the campaign before throwing more money at it.
The Right Google Ads Budget Is the One That Makes Commercial Sense
There’s no single right answer to how much you should spend on Google Ads. A solo tradie and a national eCommerce brand will have completely different numbers. What matters is that your budget is grounded in your cost per lead target, your volume goals, and the competitive reality of your market.
Start with the maths, build the campaign right, and scale once you see the numbers working. That’s how Google Ads becomes a predictable growth channel, not an expensive experiment. Not sure Google should get the first dollar at all? See how it compares with Meta and LinkedIn.
If you’re not sure whether your current Google Ads spend is doing its job, or you want to get set up properly from the start, book a free strategy call with Phoenix Marketing. We’ll walk you through exactly what a profitable setup looks like for your business.
If you would like a sanity check on your budget before you commit it, get in touch and we will run the numbers with you.
Frequently asked questions
Work backwards: decide how many leads you want, estimate how many clicks it takes to produce one lead, and multiply by your industry cost per click. That gives a realistic monthly figure rather than a guess.
Enough to buy roughly ten clicks a day in your industry. Below that, data arrives so slowly that the campaign never gets enough signal to optimise.
Yes, but weight it towards the campaigns closest to buying intent, usually exact match search on your core service terms, before spending on broader awareness.
When cost per lead has been stable for a month or more and lead quality is holding. Scale in steps of around 20 percent so the algorithm adjusts without a performance dip.