Time, Speed, Distance and Running Costs

How long will it take, when should I leave, and what will it cost? The same three-part formula answers all of these, and it is useful whether you are planning a road trip, catching a train abroad or sharing fuel costs with friends.

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One formula, three versions

• MME's speed, distance and time guide gives: speed = distance / time, time = distance / speed, and distance = speed x time.
• Keep units consistent: km and hours give km/h. MME converts 30 minutes to 0.5 hours and 90 minutes to 1.5 hours.
• To turn a decimal of an hour into minutes, multiply by 60: MME converts 0.25 hours to 15 minutes.
• Example from MME: a bus that travels 36 miles in 30 minutes has a speed of 36 / 0.5 = 72 mph.

Journey times and the decimal trap

• Worked example: 140 km at an average of 100 km/h takes 140 / 100 = 1.4 hours.
• 1.4 hours is not 1 hour 40 minutes. It is 1 hour plus 0.4 x 60 = 24 minutes, so 1 hour 24 minutes.
• Average speed includes slow parts, traffic and stops, so it is usually well below the speed limit.
• Driving faster saves less time than people think: 140 km at 120 km/h takes 70 minutes, compared with 84 minutes at 100 km/h. That is 14 minutes, at higher risk.
• Going the other way: 45 km covered in 30 minutes is 45 / 0.5 = 90 km/h average.

Planning backwards from an arrival time

• Start with when you must arrive, then subtract each part of the journey.
• Worked example: to be seated for a 9:00 exam, allow 10 minutes to park and walk, 35 minutes of driving and 15 minutes of buffer for traffic. 9:00 minus 60 minutes means leaving at 8:00.
• For trains and buses, use the 24-hour clock carefully: 17:45 is 5:45 pm. Write down the platform, the departure time and the time of the next service in case you miss it.
• If a service runs every 12 minutes, the worst case is a 12-minute wait; add it to your plan.

Fuel and running costs

• CarsGuide explains fuel consumption in litres per 100 km: fill the tank, reset the trip meter, then at the next fill divide litres used by the number of 100 km travelled. Their example: 40 litres over 500 km is 8.0 L/100 km.
• Khaleej Times reports that UAE fuel prices are set monthly, approved by the Ministry of Energy. For October 2026, Special 95 was AED 4.28 a litre and Super 98 AED 4.40.
• Worked example: a car using 8 L/100 km on a 140 km trip uses 8 x 1.4 = 11.2 litres. At AED 4.28 a litre that is about AED 47.94 one way, or about AED 95.87 return.
• Shared between four friends, the return trip costs about AED 23.97 each.
• CarsGuide warns that real-world consumption is usually worse than official test figures: a car rated at 8 L/100 km may need nearer 10 L/100 km in everyday driving. At 10 L/100 km, the same one-way trip costs about AED 59.92.
• Cost per km is a useful number: 8 L/100 km at AED 4.28 is about AED 0.34 per km.

Tank size and range

• Khaleej Times gives a typical sedan tank of 62 litres, costing AED 265.36 to fill with Special 95 in October 2026.
• Range = tank size / consumption x 100. At 8 L/100 km, 62 litres gives about 775 km.
• Do not plan to use the whole tank: in UAE summer heat, being stranded without fuel is dangerous. Refuel well before the gauge is low.
• Prices change every month, so update the price per litre before you calculate.