Pricing rental car excess as a tiny data problem (with real Tasmanian numbers)

Rental car excess is one of those decisions people make tired, at a counter, after a flight. It's also a very small data problem: a daily price, the excess you still owe, and the number of days. You can reason about it in ten lines of Python.

The hard part isn't the maths. It's getting numbers you can trust. Most hire companies in Tasmania don't publish their counter cover prices at all; they quote them when you book. One that does is Bargain Car Rentals, so I'll use its published terms as the worked example.

The inputs

For a standard car, Bargain publishes:

For context, the standard excess at other Hobart and Launceston companies that publish it sits in the same band: A$5,200 at Redspot, A$5,400 at YesDrive, A$5,500 at East Coast Car Rentals (A$6,600 for its larger vehicles).

The model

Two numbers per option: what you pay for the cover, and your worst case if the car comes back damaged (cover plus remaining excess).

from dataclasses import dataclass @dataclass class Option: name: str per_day: float # A$ a day, 0 if you keep the standard excess excess: float # A$ you still owe after damage def trip_cost(opt: Option, days: int) -> tuple[float, float]: """(what you pay for cover, worst case if the car comes back damaged)""" cover = round(opt.per_day * days, 2) return cover, round(cover + opt.excess, 2) bargain = [ Option("Standard excess", 0, 5500), Option("Gold Package", 34.99, 2500), Option("Platinum Package", 44.99, 0), ] for days in (5, 10): for o in bargain: cover, worst = trip_cost(o, days) print(f"{days:>2} days {o.name:<17} cover A${cover:>8,.2f} worst case A${worst:>9,.2f}") 

Output:

 5 days Standard excess cover A$ 0.00 worst case A$ 5,500.00 5 days Gold Package cover A$ 174.95 worst case A$ 2,674.95 5 days Platinum Package cover A$ 224.95 worst case A$ 224.95 10 days Standard excess cover A$ 0.00 worst case A$ 5,500.00 10 days Gold Package cover A$ 349.90 worst case A$ 2,849.90 10 days Platinum Package cover A$ 449.90 worst case A$ 449.90 

The interesting line isn't the cheapest one. It's the gap between the two packages: A$10 a day buys A$2,500 less exposure. Over ten days that's A$100 for A$2,500. Whether that's worth it is a personal call, but now it's a visible one.

The field the model is missing

Excess is only half the story. The other half is what the top cover still leaves out, and that doesn't fit in a float.

Reading the terms of 11 companies with a Hobart or Launceston depot: 10 of 11 still charge you for roof and underbody damage even with their top cover. Bargain's Platinum Package is the exception. Tyres and windscreens are sold as separate daily add-ons at some companies (Redspot lists a tyre waiver at A$6.21 a day and a windscreen waiver at A$17.60 a day).

Then there are road rules, which matter a lot in Tasmania:

• East Coast Car Rentals, Hertz and Thrifty don't allow unsealed roads.
• Bargain allows graded, well-maintained gravel, never the Western Explorer Road.
• Redspot allows gravel but raises your liability on it.

So the honest data model is closer to this:

@dataclass class Option: name: str per_day: float excess: float still_yours: list[str] # e.g. ["roof", "underbody"] gravel: str # "no", "graded only", "allowed, higher excess" 

The first two fields you can optimise. The last two you have to read.

Separate excess policies

The other branch is a standalone policy instead of counter cover. Two things change the maths:

1. You pay the hire company first, up to the excess, and claim it back later. Five of the companies above say so in their terms.
2. The bond still goes on your card. A separate policy doesn't remove it.

Also check the policy limit against the excess, and whether it covers roof and underbody. Some travel insurance and credit cards already include hire car excess cover, as the ACCC points out, so you may not need to buy anything.

Where the numbers come from

All figures above are from each company's own terms, read on 10 November 2026. The full table for 15 companies, with a calculator that does the comparison for your dates, is on Larkmile.

Factual information, not financial advice. Read the rental terms and the policy's PDS before you decide.