Minimum useful test budget is $1,500-3,000 over 60-90 days. Below that, you don't generate enough data to optimize. The right ongoing budget depends on cost-per-acquisition economics, not a generic percentage.
**Why $1,500-3,000 is the realistic minimum to test Google Ads:**
Google Ads needs data volume to optimize. Smart Bidding (Maximize Conversions, Target CPA, Target ROAS) requires roughly 30+ conversions per month per campaign to optimize effectively. Below that, you're running on manual bids or watching the algorithm flail.
If your average cost per conversion is $50, you need $1,500 to generate 30 conversions. If it's $100, you need $3,000. Below that data threshold, you can't tell signal from noise.
**The test budget framework:**
**Phase 1: Audit feasibility (Week 0).** Use Google Keyword Planner to estimate competitive CPC for your top 10-20 keywords. If CPC × your conversion rate × your reasonable CPA target × 30 = under your test budget, proceed. If not, your category may be too expensive for your unit economics — investigate alternatives.
**Phase 2: Test campaign (Months 1-2, $1,500-3,000).** Single search campaign, 5-10 tightly themed ad groups, 3-5 keywords per ad group, 3+ ad variations per group. Conversion tracking properly set up. Manual or Maximize Conversions bidding initially. Goal: validate that paid search can generate qualified leads/sales at acceptable cost.
**Phase 3: Optimize (Month 3, $1,500-3,000).** Cut underperforming keywords/ad groups, double down on winners, refine ad copy based on quality score and CTR data. Begin understanding cost per qualified lead/sale.
**Phase 4: Scale (Months 4+).** Once unit economics are proven, scale spend systematically — 20-30% increases per month while watching CPA. Add new keyword themes, expand to ad extensions, layer in remarketing.
**The right ongoing budget — calculated from your unit economics, not from a percentage of revenue:**
The real budget question is: "How much can I profitably spend per customer acquisition?" Not "how much should I spend overall?"
**The math:** - Average customer LTV (lifetime value): $X - Gross margin %: Y% - Acceptable customer acquisition cost (CAC): typically 25-40% of LTV × gross margin - Conversion rate of paid traffic on landing page: Z%
**Example:** average HVAC customer LTV = $4,000. Gross margin = 35%. Contribution per customer = $1,400. Acceptable CAC = 30% of contribution = $420. If your landing page converts 5% of paid clicks to leads, and 30% of leads to customers, your effective conversion rate is 1.5%. Maximum profitable cost per click = $420 × 1.5% = $6.30/click.
If the going CPC for your category is $4/click, you have margin to scale. If it's $15/click, the math doesn't work and you need either better landing pages, better lead-to-customer conversion, or different keywords.
**The $5K/month "rule of thumb" you'll hear from agencies:**
Generally a reasonable starting point for small businesses where unit economics support it. Below $2K/month, you're not generating enough data for optimization. Above $5K/month for a single-channel small business is usually only justified once you've proven the channel works at lower spend.
**Common starting-budget mistakes:**
**1. Spreading $500/month across 5 campaigns.** Each campaign gets $100/month, generates 0-3 conversions, never has enough data to optimize. Go deep on 1-2 campaigns instead.
**2. Setting daily budget too low.** Below $20-30/day, Google's algorithm has too few clicks per day to learn from. Start at $50-100/day on a single campaign.
**3. Pausing too early.** Most accounts take 30-60 days to start showing optimization gains. Pausing in week 3 because "it's not working" abandons the learning investment.
**4. Pausing too late.** Conversely, throwing $10,000 at a campaign with no conversions for 90 days is just burning money. If you're at week 4-6 with no conversions, something is fundamentally wrong (wrong keywords, wrong landing page, wrong product-market fit) — diagnose, don't keep spending.
**5. Not tracking conversions properly.** The most common cause of "Google Ads doesn't work for me" is that conversion tracking is broken or measuring the wrong thing. Fix this before spending another dollar.
**The specific things to set up before launching:**
1. Conversion tracking (Google Tag Manager + GA4 + import to Google Ads) 2. Conversion value (revenue per conversion, even if approximate) 3. Negative keywords list (words you DON'T want to show for) 4. Geo targeting (if local) 5. Day-parting if relevant (most service businesses see different conversion rates by hour/day) 6. Audience signals + remarketing audiences 7. Account-level conversion goals identified
Without these, you're driving without a speedometer. Don't start a Google Ads campaign without them.
- **What's the difference between Google Ads and Facebook Ads?** — Google Ads = paid search (intent-driven, customer is actively looking). Facebook Ads (Meta Ads) = paid social (interruption-driven, customer wasn't looking but may be interested). Different mechanics, different best uses. - **What is Quality Score and how do I improve it?** — Google's 1-10 measure of how relevant your ads, keywords, and landing pages are to a query. Higher score = lower CPC + better positions. Improve via tighter ad groups, ad relevance to keyword, and landing page experience. - **Should I bid on my brand name in Google Ads?** — Usually yes — competitors will bid on your brand if you don't, brand keywords are typically very cheap, and brand campaigns often have the highest ROAS in the account. The "I already rank organically" objection misses the point. - **What is a good CTR for Google Ads?** — Industry average is 3-5% on Search Ads, 0.5-1% on Display. Above 6% on Search is good; above 10% is excellent. Brand campaigns commonly hit 15-30% CTR. Below 2% suggests your ads or targeting need work.