Distance between cities › USA › Montana › Boulder, MT › Distance from Boulder to Custer Book Hotels

Distance from Boulder, MT to Custer, MT

Distance

279 mi

Time

5 hours 9 mins

Gas Cost

$26 - $50

There are 218.52 miles from Boulder to Custer in east direction and 279 miles (449.01 kilometers) by car, following the I-90 route.

Boulder and Custer are 5 hours 9 mins far apart, if you drive non-stop .

This is the fastest route from Boulder, MT to Custer, MT. The halfway point is Big Timber, MT.

Boulder, MT and Custer, MT are in the same time zone (MDT). Current time in both locations is 1:31 am.

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Lowest Price Rental Cars in Boulder, MT

Planning on renting a car to go from Boulder, MT to Custer, MT? Here there are some offers to rent a car in Boulder, MT

Small

From $14

Intermediate

From $18

Full-size

From $24

SUVs

From $28

Vans

From $40

Compare rental car prices in Boulder »

Gas Consumption and Emissions

A car with a fuel efficiency of MPG will need 11.21 gallons of gas to cover the route between Boulder, MT and Custer, MT.

The estimated cost of gas to go from Boulder to Custer is $36.15.

During the route, an average car will release 219.64 pounds of CO₂ to the atmosphere. The carbon footprint would be 0.79 pounds of CO₂ per mile.

Average USA gas price used for calculation is $3.23 per gallon of regular gas. Price last updated on March 13, 2026.
Read more about our CO₂ calculation.

Halfway Point Between Boulder, MT and Custer, MT

If you want to meet halfway between Boulder, MT and Custer, MT or just make a stop in the middle of your trip, the exact coordinates of the halfway point of this route are 45.814365 and -109.996201, or 45º 48' 51.714" N, 109º 59' 46.3236" W. This location is 139.57 miles away from Boulder, MT and Custer, MT and it would take approximately 2 hours 34 mins to reach the halfway point from both locations.

Closest City or Town to Halfway Point

The closest town to the halfway point is Big Timber, MT, situated 145 miles from Boulder, MT and 135 miles from Custer, MT. It would take 2 hours 26 mins to go from Boulder to Big Timber and 2 hours 15 mins to go from Custer to Big Timber.