How far is Longmont, CO from Boulder, CO?
The driving distance from Longmont, CO to Boulder, CO is about 15.6 miles (25.1 km), with a travel time of about 00h 24m by car.
- The straight-line flight distance is about 13.8 miles (22.2 km).
- For a round trip, plan for roughly 00h 49m of driving time before adding stops, traffic, or weather delays.
- A comfortable departure window is usually 7:00 AM to 7:00 PM MDT.
Reverse, save, or send this route
This is an easy same-day return drive. Copy the route link, send it to another device, or print a clean version before you head out.
This is an easy same-day return drive.
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 00h 24m.
This is a short drive, so your comfort window is wide. Traffic and current weather matter more than the clock.
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.
Census designated place
Route Weather Snapshot
Check the forecast at both ends before you head out.
Mostly Sunny
Driving Route Map
The map below follows the saved road route between Longmont and Boulder.
Turn-by-Turn Driving Directions
Step-by-step road directions between Longmont and Boulder.
-
1
Start on the route
19 m · 10 sec
-
2
Turn left onto 5th Avenue
53 m · 10 sec · 5th Avenue
-
3
Turn left onto Main Street
1286 ft · 48 sec · Main Street
-
4
Turn right onto 3rd Avenue
738 ft · 24 sec · 3rd Avenue
-
5
Turn left onto Terry Street
749 ft · 17 sec · Terry Street
-
6
Continue on South Pratt Parkway
1.1 km · 1 min · South Pratt Parkway
-
7
Turn right onto Ken Pratt Boulevard
1.6 mi · 3 min · Ken Pratt Boulevard
-
8
Continue on Diagonal Highway
9.3 mi · 12 min · Diagonal Highway
-
9
Continue on Foothills Parkway
1.9 mi · 3 min · Foothills Parkway
-
10
Turn right onto Arapahoe Avenue
1.6 mi · 4 min · Arapahoe Avenue
-
11
Turn right onto 19th Street
44 m · 11 sec · 19th Street
-
12
Turn left
27 m · 5 sec
-
13
Arrive at your destination
0 m · 1 sec
Car Route Details
A richer read on the saved driving route between Longmont and Boulder.
Turn-heavy local drive
The route has frequent decision points for its length, so lane choice and turn timing will matter more than cruising speed.
Diagonal Highway
Continue on Diagonal Highway
9.27 mi · 00h 12m
Route Summary
A quick read on whether this route feels easy, ambitious, or worth planning around.
A short regional drive
This route is short enough to handle as a quick errand, commute, or easy same-day return without much planning overhead.
Sunny leaving Longmont and Mostly Sunny near Boulder.
Trip Questions
Direct answers travelers usually want before committing to the drive.
How long does it take to drive from Longmont to Boulder?
The road trip is about 15.6 miles (25.1 km) and usually takes 00h 24m in normal driving conditions.
Is this a same-day trip or an overnight route?
This route is short enough to handle as a quick errand, commute, or easy same-day return without much planning overhead.
What is the halfway point on this route?
Niwot is a useful midpoint, sitting about 7.8 miles from Longmont and 7.8 miles from Boulder.
How much longer is the road route than the straight-line distance?
The direct path is about 13.8 miles (22.2 km), while the road route adds roughly 1.8 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 7:00 AM to 7:00 PM MDT. If you want a more comfortable same-day return, try to leave by 7:40 PM MDT.
How much will gas cost for this route?
Using about 28.3 MPG, regular gas is estimated at $2.03 one way or $4.07 round trip. Estimated CO2 is about 4.9 kg one way.
What should you check before leaving?
Before you leave, expect Sunny around Longmont and Mostly Sunny near Boulder.
Stop Ideas Near Niwot
Useful break, food, and waypoint ideas within about 15 miles of the route midpoint.
Old Town Hall
Broomfield City Council
Lafayette City Hall
Transit and Meeting Points
Useful pickup, handoff, or rendezvous points close to Niwot.
Longmont, Colorado
Boulder, Colorado
Denver (Bus Station), Colorado
Union Station
Flight Path Map
This map shows the direct air route between Longmont and Boulder. Straight-line distance: 13.79 mi (22.19 km).
#1 Longmont
The most populous city in Boulder County, Colorado.
| Population | 98,445 |
| Coordinates | 40.1672100, -105.1019300 |
| Altitude | 1519 |
| 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: (-105.27055, 40.014996)
Estimated Travel Time
Distance: 25 km by road
| Speed | Time |
|---|---|
| 30 mph (48.3 km/h) | 00h 31m |
| 40 mph (64.37 km/h) | 00h 23m |
| 50 mph (80.47 km/h) | 00h 18m |
| 60 mph (96.56 km/h) | 00h 15m |
| 70 mph (112.65 km/h) | 00h 13m |
| 80 mph (129 km/h) | 00h 11m |
Fuel, Round Trip and CO2
Estimated fuel cost and emissions for this route.
| Fuel | $/gal | One way | Round trip |
|---|---|---|---|
| Regular gas | $3.70 | $2.03 | $4.07 |
| Mid-grade | $4.08 | $2.25 | $4.49 |
| Premium | $4.39 | $2.42 | $4.83 |
| Diesel | $4.74 | $2.61 | $5.21 |
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 · Apr 23, 2026
Distance to Other Cities
Planning a road trip? See the full trip guide on Trip.ovh — stops, fuel costs, weather, and departure timing.