When is it cheaper to rent a Cummins P4500i Portable Inverter Generator by the week than by the day?

From day 4. 4 days at the $89 day rate would be $356, but the weekly rate caps it at $350.

When is it cheaper to rent a Cummins P4500i Portable Inverter Generator on the 28-day rate?

From day 17. At that point the week-and-day composition reaches the $940 28-day rate, and the price stops climbing for the rest of the cycle.

Break-even duration

Equipment rents on three rates — a day rate, a week rate and a 28-day rate — and the cheapest one changes as the job runs long. This finds the two days where it changes, on a real listing’s real published rates.

Cummins P4500i Portable Inverter Generator

See the listing →

MICHAEL PENKOFF · Generators - Gas

Day: $89
Week: $350
28 days: $940

Daily stops winning on

day 4

4 days at the day rate would be $356. On the week rate it is $350.

Weekly stops winning on

day 17

17 days at the day rate would be $1,513. On the 28-day rate it is $940.

The working

Whole weeks bill at the week rate; the leftover days bill at the day rate but never add up to more than one extra week; and a whole 28-day cycle never costs more than the 28-day rate. That is the rule, applied one day at a time.

Rental price by duration for Cummins P4500i Portable Inverter Generator, days 1 to 35
Days	At the day rate	On the ladder	Difference	Rate in play
1	$89	$89	—	day
2	$178	$178	—	day
3	$267	$267	—	day
4	$356	$350	you save $6	week
5	$445	$350	you save $95	week
6	$534	$350	you save $184	week
7	$623	$350	you save $273	week
8	$712	$439	you save $273	week
9	$801	$528	you save $273	week
10	$890	$617	you save $273	week
11	$979	$700	you save $279	week
12	$1,068	$700	you save $368	week
13	$1,157	$700	you save $457	week
14	$1,246	$700	you save $546	week
15	$1,335	$789	you save $546	week
16	$1,424	$878	you save $546	week
17	$1,513	$940	you save $573	28-day
18	$1,602	$940	you save $662	28-day
19	$1,691	$940	you save $751	28-day
20	$1,780	$940	you save $840	28-day
21	$1,869	$940	you save $929	28-day
22	$1,958	$940	you save $1,018	28-day
23	$2,047	$940	you save $1,107	28-day
24	$2,136	$940	you save $1,196	28-day
25	$2,225	$940	you save $1,285	28-day
26	$2,314	$940	you save $1,374	28-day
27	$2,403	$940	you save $1,463	28-day
28	$2,492	$940	you save $1,552	28-day
29	$2,581	$1,029	you save $1,552	day
30	$2,670	$1,118	you save $1,552	day
31	$2,759	$1,207	you save $1,552	day
32	$2,848	$1,290	you save $1,558	week
33	$2,937	$1,290	you save $1,647	week
34	$3,026	$1,290	you save $1,736	week
35	$3,115	$1,290	you save $1,825	week

Rental rates only. Protection and the marketplace service fee are added on top — see the checkout figure below.

What checkout will quote you

Rental · 17 days: $940
Rental protection (RPP): $141
Service fee: $94
Estimated total: $1,175

Pick a listing

The numbers come from one operator’s published rates, so the tool needs to know whose.

Where these numbers come from

The rates are the operator’s own, read live from their listing. The arithmetic is the same best-price billing engine that produces 2Quip invoices — not a second copy written for this page — run on the industry-standard terms: a 28-day cycle, whole weeks at the week rate, leftover days at the day rate capped at one more week.

An operator can agree different terms on an individual rental, and a long rental bills per 28-day cycle rather than in one lump. So treat this as what the rate card says, and the operator’s quote as what you are agreeing to.