Solar & battery
Solar Job Cost Calculator
Builds total job cost, where the site-specific items separate jobs of the same size.
Result
Travel time is counted because it is paid and it occupies the day, whether or not the customer sees it on the invoice. Gross profit is what is left after the cost of doing the job. Overhead comes out of that: the building, the office wages, the vans, insurance, software and advertising. A healthy gross margin still loses money if overhead is larger.
Get a Free Business AuditHow the calculation works
Material at current pricing, labour at burdened rates by trade, permitting and interconnection fees, and the site-specific items the survey identified, totalled and expressed per watt. Two jobs of identical system size can differ substantially once the site items are included.
What moves the number
- Material and labour for the design.
- Permitting and interconnection fees by jurisdiction.
- Service panel, roof and structural work identified at survey.
- Access and travel.
Where this one goes wrong
Job cost per watt is only comparable between jobs of similar size, access and jurisdiction, so an installer tracking a single average figure cannot see which job types are losing money. Track it by category. The site-specific items are also where a job's cost actually differentiates, which means the survey quality determines whether the cost is known before the price is given or discovered afterwards.
Before you quote
- Track cost per watt by job type and jurisdiction, not blended.
- Include every site-specific item the survey identified.
- Compare actual job cost against estimate afterwards.
Questions
About this calculator
Why do identical system sizes cost different amounts?
Site-specific items: service panel work, roof condition, access, conductor run length and jurisdiction fees. Those are where job cost actually differentiates, and they are identified at survey or discovered after the price was given.
Is cost per watt comparable between jobs?
Only between jobs of similar size, access and jurisdiction. An installer tracking a single average figure cannot see which job types lose money, which is why the breakdown by category is where the useful information sits.
Should actual cost be compared against estimate?
On every job, because the variance is where the estimating error lives and it is systematic rather than random. Certain job types overrun consistently, and the estimate for them has been wrong every time until somebody measures it.
The formula
cost = (job hours + travel) x crew x wage x (1 + burden%) + materials + overhead per hour
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How to use this calculator
- Labour hours (h). Enter your own figure; the page starts at 32 h.
- People on the job. Enter your own figure; the page starts at 5.
- Hourly wage ($). Enter your own figure; the page starts at $29.
- Labour burden (%). Payroll tax, insurance, holiday, training. On top of the wage.
- Materials ($). Enter your own figure; the page starts at $12,500.
- Travel hours (h). Enter your own figure; the page starts at 0.75 h.
The result updates as you type, so you can try a figure, see what it does to true job cost, and change it back. Nothing you enter is sent anywhere or saved.
A worked example
These are the figures the calculator opens with. Every number in the results column below is produced by the same calculation the page runs, so you can follow it through before putting your own figures in.
What goes in
| Input | Value |
|---|---|
| Labour hours | 32 h |
| People on the job | 5 |
| Hourly wage | $29 |
| Labour burden | 28% |
| Materials | $12,500 |
| Travel hours | 0.75 h |
| Overhead per working hour | $22 |
What comes out
| Result | Value |
|---|---|
| True job cost main result | $22,181 |
| Labour including burden | $6,078 |
| Overhead absorbed | $3,603 |
| Cost per labour hour | $135.46 |
The job costs $22,181: $6,078 of burdened labour, $12,500 of materials and $3,603 of overhead. Anything you charge below that loses money.
How sensitive the answer is
Holding everything else steady and changing only hourly wage, this is what happens to true job cost. It is worth knowing which of your inputs the answer actually hinges on, and which barely move it.
| Hourly wage ($) | True job cost |
|---|---|
| $14.5 | $19,142 |
| $21.75 | $20,661 |
| $29 example above | $22,181 |
| $43.5 | $25,220 |
| $58 | $28,259 |
Every other input is held at the example value while this one changes, which is not how a real job behaves. Treat it as a guide to which number matters most, not as five separate quotes.
What each figure means
- Labour hours (h)
- Measured in h, starting at 32 h.
- People on the job
- A number, between 0 and 30, starting at 5.
- Hourly wage ($)
- A money amount, starting at $29.
- Labour burden (%)
- Payroll tax, insurance, holiday, training. On top of the wage.
- Materials ($)
- A money amount, starting at $12,500.
- Travel hours (h)
- Measured in h, starting at 0.75 h.
- Overhead per working hour ($)
- Annual overhead divided by billable hours.
What the results tell you
| Result | What it is |
|---|---|
| True job cost | The headline result. A money figure. |
| Labour including burden | A money figure. |
| Overhead absorbed | A money figure. |
| Cost per labour hour | A money figure. |
A design still needs a site visit
Output and sizing figures use the assumptions you enter, not measured irradiance, shading or roof orientation at your address. Real production depends on all three, plus inverter behaviour and local interconnection rules.
Estimating is the easy part
The jobs you never hear about cost more than the ones you mis-measure. BDEVY builds the marketing, systems and automation that bring them in.