How far is Casper, WY from Boulder, CO?
The driving distance from Casper, WY to Boulder, CO is about 268.6 miles (432.3 km), with a travel time of about 04h 39m by car.
- The straight-line flight distance is about 204.3 miles (328.8 km).
- For a round trip, plan for roughly 09h 19m of driving time before adding stops, traffic, or weather delays.
- A comfortable departure window is usually 6:00 AM to 8:00 AM MDT.
Reverse, save, or send this route
This drive is better planned with a longer stop or an overnight stay. Copy the route link, send it to another device, or print a clean version before you head out.
This drive is better planned with a longer stop or an overnight stay.
Flight Distance
Driving Distance
Gas Cost Calculator
Leave and Arrive Planner
Pick a departure time to see your estimated arrival and same-day return window.
Drive time stays fixed at 04h 39m.
An early departure helps you fit a real stop into the day without turning the return into a late-night drive.
You are leaving earlier than the recommended window, which gives you extra margin for breaks and traffic.
Halfway Point
A useful midpoint for breaks, coffee, or meeting in the middle.
Town of the United States
Route Weather Snapshot
Check the forecast at both ends before you head out.
Chance Rain Showers
Chance Rain Showers
Driving Route Map
The map below follows the saved road route between Casper and Boulder.
Turn-by-Turn Driving Directions
Step-by-step road directions between Casper and Boulder.
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1
Start on North Sunlight Drive
1368 ft · 1 min · North Sunlight Drive
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2
Turn right
770 ft · 34 sec
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3
Turn right onto East Sunlight Drive
2655 ft · 2 min · East Sunlight Drive
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4
At the end of the road, turn right onto Bryan Stock Trail
1.1 mi · 2 min · Bryan Stock Trail
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5
Continue on North Beverly Street
1150 ft · 30 sec · North Beverly Street
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6
Turn left onto East Yellowstone Highway
1535 ft · 26 sec · East Yellowstone Highway
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7
Take the ramp straight toward I 25 South: Douglas
1542 ft · 38 sec
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8
Merge slight left
244.3 mi · 4 hr 1 min
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9
Take the exit slight right toward CO 119 West
1528 ft · 29 sec
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10
Turn right onto Highway 119
3 mi · 4 min · Highway 119
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11
Continue on East Ken Pratt Boulevard
5.4 mi · 8 min · East Ken Pratt Boulevard
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12
Continue on Diagonal Highway
9.3 mi · 12 min · Diagonal Highway
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13
Continue on Foothills Parkway
1.9 mi · 3 min · Foothills Parkway
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14
Turn right onto Arapahoe Avenue
1.6 mi · 4 min · Arapahoe Avenue
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15
Turn right onto 19th Street
44 m · 11 sec · 19th Street
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16
Turn left
27 m · 5 sec
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17
Arrive at your destination
0 m · 1 sec
Car Route Details
A richer read on the saved driving route between Casper and Boulder.
Highway-focused drive
Most of the mileage stays on named highways, so the important moments are ramps, exits, merges, and the final local approach.
I 25 South
Merge slight left
244 mi · 04h 01m
Route Summary
A quick read on whether this route feels easy, ambitious, or worth planning around.
A longer out-and-back drive
This is still possible in one day, but it becomes a long driving day. Leaving early and planning your stop window matters more here.
Chance Rain Showers leaving Casper and Chance Rain Showers near Boulder.
Trip Questions
Direct answers travelers usually want before committing to the drive.
How long does it take to drive from Casper to Boulder?
The road trip is about 268.6 miles (432.3 km) and usually takes 04h 39m in normal driving conditions.
Is this a same-day trip or an overnight route?
This is still possible in one day, but it becomes a long driving day. Leaving early and planning your stop window matters more here.
What is the halfway point on this route?
Chugwater is a useful midpoint, sitting about 134.3 miles from Casper and 134.3 miles from Boulder.
How much longer is the road route than the straight-line distance?
The direct path is about 204.3 miles (328.8 km), while the road route adds roughly 64.3 extra miles because roads do not follow the straight air line.
When is the best time to leave for this route?
A good departure window is usually 6:00 AM to 8:00 AM MDT. If you want a more comfortable same-day return, try to leave by 7:40 AM MDT.
How much will gas cost for this route?
Using about 28.3 MPG, regular gas is estimated at $42.56 one way or $85.11 round trip. Estimated CO2 is about 84.2 kg one way.
What should you check before leaving?
Before you leave, expect Chance Rain Showers around Casper and Chance Rain Showers near Boulder.
Stop Ideas Near Chugwater
Useful break, food, and waypoint ideas within about 15 miles of the route midpoint.
Transit and Meeting Points
Useful pickup, handoff, or rendezvous points close to Chugwater.
Wheatland, Wyoming
Cheyenne, Wyoming
Douglas, Wyoming
Flight Path Map
This map shows the direct air route between Casper and Boulder. Straight-line distance: 204.29 mi (328.77 km).
#1 Casper
The most populous city in Natrona County, Wyoming.
| Population | 58,498 |
| Coordinates | 42.8666300, -106.3130800 |
| Altitude | 1560 |
| Country | United States |
#2 Boulder
The most populous city in Boulder County, Colorado.
| Population | 107,645 |
| Coordinates | 40.0149900, -105.2705500 |
| Altitude | 1624 |
| Country | United States |
End: Boulder (-105.27055, 40.01499)
Estimated Travel Time
Distance: 432 km by road
| Speed | Time |
|---|---|
| 30 mph (48.3 km/h) | 08h 56m |
| 40 mph (64.37 km/h) | 06h 42m |
| 50 mph (80.47 km/h) | 05h 22m |
| 60 mph (96.56 km/h) | 04h 28m |
| 70 mph (112.65 km/h) | 03h 50m |
| 80 mph (129 km/h) | 03h 21m |
Fuel, Round Trip and CO2
Estimated fuel cost and emissions for this route.
| Fuel | $/gal | One way | Round trip |
|---|---|---|---|
| Regular gas | $4.49 | $42.56 | $85.11 |
| Mid-grade | $4.76 | $45.12 | $90.23 |
| Premium | $5.07 | $48.10 | $96.20 |
| Diesel | $6.18 | $58.59 | $117.17 |
Assumes 8.3 L/100 km (about 28.3 MPG). CO2 is an estimate and varies by vehicle, fuel blend, traffic, and terrain.
Prices in Wyoming · Oct 13, 2026