How far is Boulder, CO from Casper, WY?
The driving distance from Boulder, CO to Casper, WY is about 268.6 miles (432.2 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 18m 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.
Rain Showers Likely
Chance Rain And Snow Showers then Partly Sunny
Driving Route Map
The map below follows the saved road route between Boulder and Casper.
Turn-by-Turn Driving Directions
Step-by-step road directions between Boulder and Casper.
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1
Start on the route
27 m · 7 sec
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2
Turn right onto 19th Street
44 m · 14 sec · 19th Street
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3
Turn left onto Arapahoe Avenue
1.6 mi · 4 min · Arapahoe Avenue
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4
Turn left onto Foothills Parkway
2.5 mi · 4 min · Foothills Parkway
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5
Continue on Diagonal Highway
8.6 mi · 11 min · Diagonal Highway
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6
Continue on Ken Pratt Boulevard
5.4 mi · 8 min · Ken Pratt Boulevard
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7
Continue on Highway 119
3.1 mi · 4 min · Highway 119
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8
Turn left onto I 25 North
1400 ft · 34 sec
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9
Merge slight left onto Dwight D. Eisenhower Highway
244.8 mi · 4 hr 1 min · Dwight D. Eisenhower Highway
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10
Take the exit slight right toward I 25 Business, US 20, US 26, US 87: North Beverly Street, Bryan Stock Trail
670 ft · 16 sec
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11
Turn straight onto East F Street
99 m · 10 sec · East F Street
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12
Turn right onto Bryan Stock Trail
1.1 mi · 2 min · Bryan Stock Trail
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13
Turn left onto East Sunlight Drive
1.5 km · 4 min · East Sunlight Drive
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14
Arrive at your destination
0 m · 1 sec · North Sunlight Drive
Car Route Details
A richer read on the saved driving route between Boulder and Casper.
Highway-focused drive
Most of the mileage stays on named highways, so the important moments are ramps, exits, merges, and the final local approach.
Dwight D. Eisenhower Highway
Merge slight left onto Dwight D. Eisenhower Highway
245 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.
Rain Showers Likely leaving Boulder and Chance Rain And Snow Showers then Partly Sunny near Casper.
Trip Questions
Direct answers travelers usually want before committing to the drive.
How long does it take to drive from Boulder to Casper?
The road trip is about 268.6 miles (432.2 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 Boulder and 134.3 miles from Casper.
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 7:42 AM MDT.
How much will gas cost for this route?
Using about 28.3 MPG, regular gas is estimated at $41.00 one way or $82.00 round trip. Estimated CO2 is about 84.2 kg one way.
What should you check before leaving?
Before you leave, expect Rain Showers Likely around Boulder and Chance Rain And Snow Showers then Partly Sunny near Casper.
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.
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Flight Path Map
This map shows the direct air route between Boulder and Casper. Straight-line distance: 204.29 mi (328.77 km).
#1 Boulder
The most populous city in Boulder County, Colorado.
| Population | 107,645 |
| Coordinates | 40.0149900, -105.2705500 |
| Altitude | 1624 |
| Country | United States |
#2 Casper
The most populous city in Natrona County, Wyoming.
| Population | 58,498 |
| Coordinates | 42.8666300, -106.3130800 |
| Altitude | 1560 |
| Country | United States |
End: Casper (-106.31308, 42.86663)
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 | $4.33 | $41.00 | $82.00 |
| Mid-grade | $4.72 | $44.74 | $89.47 |
| Premium | $5.06 | $48.00 | $95.99 |
| Diesel | $6.52 | $61.78 | $123.56 |
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 Colorado · Oct 15, 2026