LawnBiz Tools

Mower Payback Calculator

A faster machine saves hours. Hours are only worth money if you sell them — so this asks how many you would actually re-sell, and answers honestly when the answer is "never".

Time to pay for itself —

Enter your numbers below.

The machine, and the work it would do

Pre-filled with the worked example below. Change every field to your own numbers.

Total turf across the route.
From the hourly rate calculator.
Wage, fuel and wear for an hour of work. Not overhead.
Be honest. 0 means you just finish earlier.

These are your numbers, not market rates. This calculator works from the costs you enter. It does not tell you what your area pays — that varies by region, season and year, and any site quoting you a single national figure is guessing. Use this to find the price that covers your costs and target profit, then sanity-check it against what you can actually win locally.

The formula and a worked example Show the arithmetic 
acres/hour   = (mph x deck / 99) x efficiency
hours        = weekly acres / acres per hour
hours saved  = old hours - new hours

contribution = charge-out rate - variable cost per hour
hours sold   = hours saved x share you re-sell
revenue gain = hours sold x contribution

running delta = new hours x new $/hr - old hours x old $/hr
gain per week = revenue gain - running delta

weeks to payback = (price - trade-in) / gain per week

Two things in there are easy to get wrong. A re-sold hour is worth its contribution, not the full rate — working it costs money too. And the running-cost comparison has to use hours as well as rates, because the faster machine runs fewer of them.

Worked example

$11,000 mower, $2,000 trade-in, 12 acres a week
48in at 5 mph now, 60in at 8 mph new, 80% efficiency
$62.54/hr charge-out, $8/hr variable, 50% of saved time re-sold
$4/hr running now, $6/hr running new, 30-week season

acres/hour   old (5 x 48 / 99) x 0.8   = 1.9394 ac/hr
             new (8 x 60 / 99) x 0.8   = 3.8788 ac/hr

hours/week   old 12 / 1.9394           = 6.1875 hr
             new 12 / 3.8788           = 3.0938 hr
hours saved                            = 3.0938 hr

contribution 62.54 - 8.00              = $54.54
hours sold   3.0938 x 0.50             = 1.5469 hr
revenue gain 1.5469 x 54.54            = $84.37

running      old 6.1875 x 4            = $24.75
             new 3.0938 x 6            = $18.56
running delta                          = -$6.19   (a saving)

gain/week    84.37 + 6.19              = $90.55
payback      9,000 / 90.55             = 99.4 weeks
                                       = 3.3 seasons

The running-cost line is the one that surprises people. The new machine burns 50% more per hour and still costs $6.19 a week less to run, because it does the same work in half the time.

Set the re-sell share to 0% and the answer collapses. With no extra work sold, the only gain left is the $6.19 of running cost, and $9,000 at $6.19 a week takes 1,455 mowing weeks — about 48 seasons. The machine will be scrap long before it pays for itself on fuel alone.

That is the number an equipment brochure will not show you, and it is the whole point of the re-sell input. Everything that makes this purchase work comes from selling the time, not from saving the fuel.

Three and a bit seasons is not a bad answer

A commercial mower that pays for itself in three seasons and then keeps running is a good purchase, and the resale value at the end is not counted here at all. The point of the calculation is not to talk you out of the machine — it is to make sure the case rests on work you will genuinely sell rather than on hours you will simply not be working.

If your honest re-sell share is low, the machine may still be worth buying for reasons this calculator cannot price: less fatigue, a better cut, one less breakdown in August. Those are real. They are just not payback.

Common questions

Is a zero-turn worth it?

Only if you sell the time it saves. That is the whole answer, and it is the part equipment sales material leaves out.

A faster machine converts hours into free hours. Free hours are worth money only when you fill them with work someone pays for. If you finish at three instead of five and go home, the machine bought you an earlier finish — which may be exactly what you want, but it will not make the payment.

The calculator asks what share of the saved time you would actually re-sell. Set it to zero and the payback stretches to decades, because the only gain left is a little fuel - which is the honest answer, and not the one on the sales floor.

Why is the value of a saved hour less than my hourly rate?

Because working that hour costs money too. Fuel, blades, wear and the wage for the hour all come out of the rate before anything is left over.

What a re-sold hour is worth is its contribution: your charge-out rate minus the variable cost of working it. On a $62.54 rate with $8 of variable cost, an extra hour is worth $54.54, not $62.54. Using the full rate overstates payback by about 15%.

A bigger machine burns more fuel. Does that not cancel the gain?

Usually not, and the arithmetic is less obvious than it looks. Running cost depends on the rate AND the hours, and the faster machine runs far fewer hours.

In the worked example the new mower burns $6 an hour against the old one's $4 — 50% more per hour — but it does the same work in half the time. Weekly running cost falls from $24.75 to $18.56. The thirstier machine is $6.19 a week cheaper to run.

Enter both rates and the calculator does that comparison properly rather than assuming.

Should I include the finance payment?

Not in this calculation. This answers "how long until the machine has earned back what it cost", which is a question about the asset, not about how you paid for it.

If you are financing, put the monthly payment in your fixed costs in the overhead calculator instead. That is where it belongs, and it will flow through to your hourly rate on its own.

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