How far is Saint Peters, MO from Arnold, MO?

The driving distance from Saint Peters, MO to Arnold, MO is about 39.9 miles (64.2 km), with a travel time of about 00h 51m by car.

  • The straight-line flight distance is about 28.7 miles (46.2 km).
  • For a round trip, plan for roughly 01h 42m of driving time before adding stops, traffic, or weather delays.
  • A comfortable departure window is usually 8:00 AM to 10:00 AM CDT.
Trip Tools

Reverse, save, or send this route

This route works well as a day trip with time at the destination. Copy the route link, send it to another device, or print a clean version before you head out.

Reverse Route
Quick Snapshot
Road
39.9 mi
00h 51m
Flight
28.73 mi
46.23 km direct

This route works well as a day trip with time at the destination.

Learn Distance

Choose another destination from Saint Peters.

Flight Distance

Direct air line
28.73 mi
Kilometers
46.23 km
Flight Time
00h 03m

Driving Distance

Road route
39.9 mi
Kilometers
64.22 km
Drive Time
00h 51m

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 51m.

Arrival Snapshot
Arrive in Arnold
Thu, Apr 16, 2:44 AM CDT
Return by in Saint Peters
Thu, Apr 16, 3:35 AM CDT
Useful when you're deciding between a quick errand, a day trip, or a longer stop.
Leave Saint Peters
2026-04-16T01:53
Arrive Arnold
Thu, Apr 16, 2:44 AM CDT
Route Timing
00h 51m
One way by road
Best Departure Window
8:00 AM to 10:00 AM CDT
Aim for a morning departure
Arrive between
8:51 AM to 10:51 AM CDT

A morning start gives you useful time at the destination and keeps the return out of the late evening.

Leave by
4:48 PM CDT
Keeps a same-day return open with about 03h 00m at the destination.
Back in Saint Peters
9:30 PM CDT
Morning start is best

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.

Mid-route stop
Westwood
MO

Village in west St.

From Saint Peters
19.9 mi
00h 25m
To Arnold
19.9 mi
00h 25m

Route Weather Snapshot

Check the forecast at both ends before you head out.

Origin
82°F
Thursday

Chance Rain Showers

Starts
Thu, Apr 16 6:00 AM CDT
Wind
7 to 10 mph SW
Destination
82°F
Thursday

Chance Rain Showers then Chance Showers And Thunderstorms

Starts
Thu, Apr 16 6:00 AM CDT
Wind
8 mph SW

Driving Route Map

The map below follows the saved road route between Saint Peters and Arnold.

Turn-by-Turn Driving Directions

Step-by-step road directions between Saint Peters and Arnold.

  1. 1

    Start on the route

    1.2 mi · 1 min

  2. 2

    Take the exit slight right toward MO 79: Elsberry, Louisiana

    725 ft · 15 sec

  3. 3

    Keep slight left to continue on MO 79

    117 m · 15 sec

  4. 4

    Turn left

    652 ft · 11 sec

  5. 5

    Take the ramp slight right toward I 70 East

    1294 ft · 19 sec

  6. 6

    Merge slight left

    11.9 mi · 15 min

  7. 7

    Take the exit slight right toward I 270: Chicago, Memphis

    872 ft · 12 sec

  8. 8

    Keep slight right to continue on I 270 South: Memphis

    2339 ft · 33 sec

  9. 9

    Continue on I 270 South: Memphis

    723 ft · 10 sec

  10. 10

    Merge slight left

    19 mi · 24 min

  11. 11

    Take the exit slight right toward I 55, US 61, US 67: Saint Louis, Memphis, Lemay Ferry Road

    1911 ft · 27 sec

  12. 12

    Keep slight right to continue on I 55 South: Memphis

    2031 ft · 44 sec

  13. 13

    Merge slight left onto Rosa Parks Highway

    1.5 mi · 2 min · Rosa Parks Highway

  14. 14

    Continue on Officer Thomas G. Smith, Jr. Memorial Highway

    1.8 mi · 2 min · Officer Thomas G. Smith, Jr. Memorial Highway

  15. 15

    Continue on Police Officer Steven Jarvis Memorial Highway

    1.5 km · 1 min · Police Officer Steven Jarvis Memorial Highway

  16. 16

    Take the exit slight right toward MO 141: Arnold

    1143 ft · 28 sec

  17. 17

    Keep slight left to continue on MO 141 South: Arnold

    134 m · 13 sec

  18. 18

    Merge slight right

    893 ft · 14 sec

  19. 19

    Continue straight

    879 ft · 21 sec

  20. 20

    Turn right onto Jeffco Boulevard

    1.4 km · 2 min · Jeffco Boulevard

  21. 21

    Arrive at your destination

    0 m · 1 sec · Jeffco Boulevard

Car Route Details

A richer read on the saved driving route between Saint Peters and Arnold.

OSRM road route
Drive Character

Highway-focused drive

Most of the mileage stays on named highways, so the important moments are ramps, exits, merges, and the final local approach.

Directions
21 steps
2 turns on the saved route
Ramps & Exits
9
4 merges, 5 ramps or exits
Navigation Density
52.6 / 100 mi
Decision points by distance
Main Roads
I 270 South
19.6 mi · 49%
I 70 East
12.1 mi · 30%
Rosa Parks Highway
1.51 mi · 4%
Police Officer Steven Jarvis Memorial Highway
0.94 mi · 2%
Officer Thomas G. Smith, Jr. Memorial Highway
0.92 mi · 2%
Officer Thomas G. Smith
0.92 mi · 2%
Longest Stretch

I 270 South

Merge slight left

19 mi · 00h 24m

Route Summary

A quick read on whether this route feels easy, ambitious, or worth planning around.

Trip Read

A comfortable day-trip route

This route works well as a day trip. You can leave in the morning, spend meaningful time at the destination, and still return the same day.

Drive Time
00h 51m
Day trip friendly
Same-Day Return
01h 42m
Round-trip wheel time
Road vs Air
+11.2 mi
28.7 mi direct line
Halfway Stop
Westwood
00h 25m from Saint Peters
Leave By
4:48 PM CDT
Morning start is best
Weather Watch

Chance Rain Showers leaving Saint Peters and Chance Rain Showers then Chance Showers And Thunderstorms near Arnold.

Trip Questions

Direct answers travelers usually want before committing to the drive.

How long does it take to drive from Saint Peters to Arnold?

The road trip is about 39.9 miles (64.2 km) and usually takes 00h 51m in normal driving conditions.

Is this a same-day trip or an overnight route?

This route works well as a day trip. You can leave in the morning, spend meaningful time at the destination, and still return the same day.

What is the halfway point on this route?

Westwood is a useful midpoint, sitting about 19.9 miles from Saint Peters and 19.9 miles from Arnold.

How much longer is the road route than the straight-line distance?

The direct path is about 28.7 miles (46.2 km), while the road route adds roughly 11.2 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 8:00 AM to 10:00 AM CDT. If you want a more comfortable same-day return, try to leave by 4:48 PM CDT.

How much will gas cost for this route?

Using about 28.3 MPG, regular gas is estimated at $5.32 one way or $10.63 round trip. Estimated CO2 is about 12.5 kg one way.

What should you check before leaving?

Before you leave, expect Chance Rain Showers around Saint Peters and Chance Rain Showers then Chance Showers And Thunderstorms near Arnold.

Stop Ideas Near Westwood

Useful break, food, and waypoint ideas within about 15 miles of the route midpoint.

Mid-route Guidance
Local place coverage is thin around Westwood, so nearby transit and meeting points are shown instead.
Reviewed stop coverage is still thin around this midpoint, so practical transit waypoints are shown on the right.

Transit and Meeting Points

Useful pickup, handoff, or rendezvous points close to Westwood.

RAIL

Kirkwood

8 mi away
110 West Argonne Dr.
RAIL

Gateway Transportation Center

20 mi away
551 South 16th St.
RAIL

Alton

39 mi away
3400 College Ave.
RAIL

Washington

51 mi away
301 West Front St.

Flight Path Map

This map shows the direct air route between Saint Peters and Arnold. Straight-line distance: 28.73 mi (46.23 km).

Saint Peters

#1 Saint Peters

The most populous city in St.

Population58,043
Coordinates38.8003300, -90.6265100
Altitude134
CountryUnited States
Arnold

#2 Arnold

City in Missouri

Population21,145
Coordinates38.4328300, -90.3776200
Altitude184
CountryUnited States
Start: Saint Peters (-90.62651, 38.80033)
End: Arnold (-90.37762, 38.43283)

Estimated Travel Time

Distance: 64 km by road

SpeedTime
30 mph (48.3 km/h)01h 19m
40 mph (64.37 km/h)00h 59m
50 mph (80.47 km/h)00h 47m
60 mph (96.56 km/h)00h 39m
70 mph (112.65 km/h)00h 34m
80 mph (129 km/h)00h 29m

Fuel, Round Trip and CO2

Estimated fuel cost and emissions for this route.

One-way fuel
1.41 gal
5.33 L · about $5.32
Round trip
$10.63
2.82 gal · 10.66 L
Estimated CO2
12.5 kg one way
Round trip: 25.1 kg / 55 lb CO2, using regular gasoline.
Fuel$/galOne wayRound trip
Regular gas $3.77 $5.32 $10.63
Mid-grade $4.25 $6.00 $11.99
Premium $4.65 $6.56 $13.12
Diesel $5.30 $7.48 $14.96

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 Missouri · Apr 16, 2026

There is no time difference between Saint Peters and Arnold. The current time is 01:53:04.

Distance to Other Cities

Planning a road trip? See the full trip guide on Trip.ovh — stops, fuel costs, weather, and departure timing.

How did we calculate? Place names are translated into coordinates. The Haversine formula calculates straight-line distance; driving distance uses road network data.