Plumber Flat-Rate Price Calculator · comparison
Short answer: time and materials bills the hours that happen; a flat rate bills the hours you promised. The calculator prices the flat rate from your true cost and shows the clock bill next to it, so you can see how far a job can run before the flat price stops paying.
Everything below is arithmetic on invented numbers and names no company or software product. Not business, tax, legal or licensing advice. No warranty.
You bill an hourly rate for the time worked, usually with travel, plus parts at cost and a markup. The customer does not know the total until the work is done, and you are paid for a slow job and a fast one in proportion to the clock. It is the simplest thing to explain on a call and the hardest for a customer to compare with another quote.
A price agreed before the work, from a price book: the same job, the same number. It moves the risk of a long job from the customer to you, and the reward of a fast job from the customer to you. Customers can compare it; you must know your cost to set it.
The default job is 2 hours on site, 0.75 hours of travel and $120.00 of parts, at a true cost of $100.00 an hour. The flat price is $595.00. On the clock at $135.00 an hour the bill is 2.75 x $135.00 + $198.00 of parts = $569.25. The two bills match at 2.94 hours.
| Hours worked | Clock bill | Your profit, clock | Flat price | Your profit, flat |
|---|---|---|---|---|
| 1.65 (60%) | $420.75 | $135.75 | $595.00 | $310.00 |
| 2.75 (plan) | $569.25 | $174.25 | $595.00 | $200.00 |
| 4.125 (150%) | $754.88 | $222.38 | $595.00 | $62.50 |
| 5.5 (200%) | $940.50 | $270.50 | $595.00 | -$75.00 |
Check your local licensing and written-estimate rules for how a price must be quoted.
Neither is better on its own; the difference is who carries the hours. On the default numbers the flat price is $595.00 and time and materials at $135.00 an hour bills $569.25 at the planned 2.75 hours, so the two bills match at 2.94 hours.
At 4.125 hours, 50 percent over plan, the flat price of $595.00 leaves $62.50 against $222.38 on the clock. At 5.5 hours it loses $75.00 while time and materials still earns $270.50.
When you finish faster than the book time. At 60 percent of the planned hours the flat price leaves $310.00 against $135.75 on the clock, and the customer pays more than the clock would have charged.
No. It is arithmetic on invented numbers; check every figure against your own records. Not business, tax, legal or licensing advice. No warranty.