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Speed Distance Time Calculator
Calculate any of the three variables — speed, distance, or time — when you know the other two. Essential for travel planning, physics problems, running pace calculation, and estimating arrival times for driving, cycling, or walking trips.
The speed-distance-time relationship is one of the most fundamental calculations in everyday life — from estimating arrival times on road trips to calculating running pace to solving physics problems. Enter any two values to instantly find the third.
Speed, Distance and Time in Travel
The SDT triangle is a fundamental tool for travel planning. Knowing any two variables allows you to calculate the third. This applies to all forms of transportation — from walking (3-4 mph) to cycling (10-20 mph) to driving (30-70 mph) to flying (500-600 mph) to high-speed rail (180-220 mph).
Mode
Typical Speed
Per Mile
Reference
Walking
3-4 mph (4.8-6.4 km/h)
1 mile = 15-20 min
5K = 45-60 min
Cycling (casual)
10-15 mph (16-24 km/h)
1 mile = 4-6 min
5K = 8-12 min
Cycling (sport)
18-25 mph (29-40 km/h)
1 mile = 2.5-3.5 min
5K = 6-8 min
City driving
20-30 mph avg
1 mile = 2-3 min
Traffic dependent
Highway driving
60-70 mph
1 mile = 51-60 sec
100 miles = 1.5 hr
Commercial flight
500-575 mph
1 mile = ~7 sec
NYC-LA = 5.5 hr
Average Speed vs Constant Speed
This calculator uses average speed for the entire trip. In reality, speed varies — you stop at traffic lights, slow in construction zones, speed on open highway. Average speed = Total Distance / Total Time including all stops. If you drive 120 miles in 2.5 hours including a 20-minute food stop, your average speed = 120/2.5 = 48 mph, but your driving speed was higher.
Time Zone Considerations for Flight Time
Flight times are typically reported in local times at destination. A 5-hour flight from New York (EST) to Los Angeles (PST) departing at 8am arrives at 11am PST — a 3-hour clock time difference due to crossing 3 time zones, despite 5 hours of actual flight time. Always calculate arrival time in destination time zone.
Frequently Asked Questions
Time = Distance / Speed. For 250 miles at 65 mph: 250/65 = 3.846 hours = 3 hours 51 minutes. For km/h: 400 km at 100 km/h = 4 hours. Remember to account for stops — add 15-30 minutes per 2-3 hours of driving for rest stops.
At 60 mph: 100/60 = 1.667 hours = 1 hour 40 minutes. At 70 mph: 1 hour 26 minutes. At 55 mph: 1 hour 49 minutes. At 30 mph (city): 3 hours 20 minutes. These are driving-only times — add time for stops, traffic, and navigation errors in trip planning.
Average door-to-door speed (including stops) on US interstate highway road trips: 50-55 mph. Even at 70 mph driving speed, stops for gas, food, and rest reduce the effective average. Plan on 500-600 miles per day as a comfortable maximum for long road trips with standard rest stops.
Distance = Speed × Time. At 65 mph for 3 hours: 65 × 3 = 195 miles. At 100 km/h for 4 hours: 400 km. For cycling: 15 mph × 2 hours = 30 miles. For walking: 3.5 mph × 4 hours = 14 miles.
Speed = Distance / Time. If you have 200 miles to cover in 3 hours: 200/3 = 66.7 mph required average speed. Remember average speed includes all stops — if you need 66.7 mph average with a 30-minute food stop, your actual driving speed needs to be higher to compensate.
The speed of light is approximately 186,282 miles per second (299,792 km/s). At this speed: it takes light about 1.3 seconds to travel from the Moon to Earth, 8 minutes from the Sun to Earth, and 4.24 years from the nearest star (Proxima Centauri) to Earth.