Every article answering this question hands you someone else's number. None of those numbers survive contact with your market: the same search term costs $7 a click in one metro and $35 in another, so a budget that drowns one shop starves the next. This post will not hand you a number. It will hand you the arithmetic that computes yours.
Key takeaways
- Five inputs from your own account and CRM compute your real budget
- The same goal can honestly cost $3,700 in one market and $13,000 in another
- Close rate and contact rate are the levers that buy more jobs without new spend
The five numbers that set your budget
Your market's real cost per click. Pull your actual terms in your zip codes from Google's Keyword Planner. Emergency terms run $20 to $40 in competitive metros, single digits in small markets. This input alone can move the budget by a multiple of four.
Your click to lead conversion rate. Forms alone convert in the low single digits, which is why calls carry the weight in this industry: 60 percent of customers prefer to call, per CallRail's 2026 research.
Your contact rate. The share of leads you actually get on the phone. Businesses miss about 14 percent of calls, and reaching a lead within an hour is roughly 60× more effective than waiting a day, per Harvard Business Review.
Your close rate. Spoke with 50, booked 20: that is 40 percent, or 0.40. Pull it from your own CRM, never a benchmark.
Your average job value and mix. A $99 tune up and a $15,000 replacement ride the same click. Budget gets set against what a booked job returns, never against what a lead costs.
The math, run in two different markets
Same trade, same goal: 20 additional booked jobs a month at a 40 percent close rate and 80 percent contact rate. That requires about 63 leads. Watch what the market does to the budget.
| Dense metro shop | Small market shop |
|---|---|
| $25 average cost per click on its terms | $7 average cost per click on the same terms |
| 12 percent of clicks become a lead: about $208 per lead | 12 percent of clicks become a lead: about $58 per lead |
| 63 leads × $208 = roughly $13,000 per month | 63 leads × $58 = roughly $3,700 per month |
Identical business, identical goal, three and a half times the budget, and both numbers are right. That is why any article that opens with a monthly range is guessing about somebody.
Benchmarks are a floor, not a forecast
| $6.59 | average home services click across 3,211 US campaigns |
| $45–79 | average cost per lead, from HVAC through roofing |
| 69% | of advertisers saw cost per lead rise year over year, at an average of 10.51 percent |
Data: LocaliQ benchmark of 3,211 US home services campaigns. Those averages blend every market size and service mix; competitive metros run multiples higher. Below roughly $2,000 to $5,000 a month in an expensive market, the bidding system starves and Local Services Ads are usually the smarter entry.
Why two identical budgets produce different results
Budget only buys the auction entry. What the system learns decides what the dollars return: an account optimizing toward cheap form fills teaches Google to hunt form fillers, while an account feeding booked revenue back teaches it to hunt buyers, per Google's value based bidding guidance. Same spend, different definition of success, different business.
Timing compounds it. Per ServiceTitan's analysis of roughly 800 HVAC shops, weather events lift daily revenue 55 percent, and the first heat wave of the season lifts it roughly 90 percent.
The right spend is not a number. It is a number that breathes.
Questions owners ask about Google Ads budgets
What is the formula for a Google Ads budget?
Monthly budget = (booked jobs goal ÷ close rate ÷ contact rate) × (cost per click ÷ click to lead conversion rate). The first bracket computes the leads you need, the second computes what a lead costs in your market. All five inputs come from your own account and CRM, not from a benchmark table.
Is $1,000 a month enough?
It depends entirely on your market. In a small market with single digit clicks, $1,000 can buy meaningful lead flow. In a competitive metro where emergency terms run $20 to $40 a click, it buys 25 to 50 clicks a month, which starves the bidding system and produces noise. Below the data threshold for your market, Local Services Ads are usually the better entry.
How long before I can judge the results?
A new account needs 90 days minimum before conclusions mean anything. The first 60 days are paid data collection while the bidding system learns which clicks become customers. An existing account with history can improve within 30 days.
Why does my cost per lead keep rising?
You are not alone: cost per lead rose for 69 percent of advertisers year over year, at an average of 10.51 percent. Rising competition explains part of it. The controllable part is what your account tells Google to optimize toward, because a system aimed at cheap form fills gets exactly that.
Should the budget change through the year?
Yes. Weather events lift daily HVAC revenue by 55 percent and the first heat wave of the season lifts it roughly 90 percent. A flat budget underspends those windows and overspends the quiet ones.
Deciding between the auction and the Verified box is its own decision: Local Services Ads vs Google Ads: Which One Books More Jobs? And for what a lead truly costs after the click, start with Cost Per Lead Is Lying to You.
Sources: Google Keyword Planner · LocaliQ 2025 Home Services Benchmarks · Google Value Based Bidding Guide · Harvard Business Review · CallRail 2026 Research · ServiceTitan