How this calculator works
upfront = generator + transfer switch + gas line + pad + labor + permits
total = upfront + (yearly maintenance × years)What each input means
| Input | What it is actually asking |
|---|---|
| Generator | The unit at the size the dealer proposed. Check it against the sizing tool. |
| Transfer switch | The safety-critical part: it keeps the generator from backfeeding the utility line. |
| Gas line, pad, permits | Local lines. Placement clearances are set locally. |
| Maintenance and years | Scheduled service as quoted in writing. |
Worked examples
Including one where the naive answer misleads, which is the example most calculators leave out.
Two bids, different switches
One bid includes a whole-house switch, the other a managed-circuit switch with a smaller unit. Type both. The upfront gap may be mostly the unit size; ask which loads each one actually runs.
Ownership over ten years
Set years to 10 and type the quoted yearly service. A bid that looks lower upfront can close the gap if its service plan costs more.
What changes the result
Size moves everything else: a larger unit needs more fuel capacity and sometimes a bigger gas line. See how to compare two brand bids.
When not to use this
Not a quote and not a sizing study. Never run a portable generator indoors or in a garage, and never connect one through an outlet.
Questions this calculator answers
- What drives the cost of a standby generator?
- Size, the transfer switch type, gas line work, the pad and placement rules, labor and the permit. Size is set by the loads that must run, especially the largest motor that must start.
- Why no typical prices?
- We hold no sourced, dated set of generator quotes. Type what your bid says.
- Should I include maintenance?
- Yes, if you want the cost of ownership. Ask the dealer for the yearly service price in writing and type it.
- Is a portable generator a cheaper option?
- It can be, but it must run outdoors, at least 20 feet from the house, and it must connect through a transfer switch or interlock, never an outlet. See the CPSC guidance.
- Does fuel cost appear here?
- No. Fuel depends on outage hours and your gas or propane price. Use the outage cost tool to judge how often you need backup.
Sources and methodology
Figures dated 26 October 2026. Last reviewed .
- CPSC warns of generator, carbon monoxide and fire hazards (May 2026) (U.S. Consumer Product Safety Commission, retrieved Checked October 26, 2026. Operate generators outdoors only, at least 20 feet from homes and buildings.)
Related
- Generator sizing Watts first.
- Outage cost Whether backup is worth it.
- Generac vs Kohler How to compare two brand bids.
- Generator installation What the job involves.