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06 Numbers and Powers

CF Card vs SD: Which Should You Use?

Card No. 06·37823 · Updated · Standard formula, shown below

Average pace 5.00 min/km
Average speed
12.00 km/h
Result
Finish time
50 min
You entered
Distance
10 km
You entered
You enter
Finish time, Distance
You get
Average pace, Average speed
Rounding
2 dp

CF (CompactFlash) and SD (Secure Digital) cards are two different flash memory formats used to store photos, videos, and other data. CF cards are older, larger, and historically faster and more durable, while SD cards are smaller, more common, and now offer comparable speeds in many cases. Your choice depends on your device’s slot and the performance you need.

Formula

The calculator above works out your average running pace and speed. The formulas are:

  • Pace (min/km) = Finish time (minutes) ÷ Distance (km)
  • Speed (km/h) = Distance (km) ÷ (Finish time (minutes) ÷ 60)

Where:

  • Finish time is the total time taken, in minutes.
  • Distance is the distance covered, in kilometers.
  • Pace is the time per kilometer, in minutes and seconds.
  • Speed is the average speed, in kilometers per hour.

Worked Example

Using the default values: finish time = 50 minutes, distance = 10 km.

  1. Pace = 50 ÷ 10 = 5.00 min/km (which is 5:00 per km).
  2. Speed = 10 ÷ (50 ÷ 60) = 10 ÷ 0.8333 = 12.00 km/h.

The calculator shows a pace of 5.00 min/km and a speed of 12.00 km/h.

When to Use This Pace Calculator

Use this calculator when you want to know your average pace for a run, walk, or cycle. It is useful for training plans, race predictions, or simply tracking your fitness. Enter the total time and distance, and you get the two most common metrics: pace per kilometer and average speed. Many runners prefer pace, while cyclists often think in speed. The calculator gives both.

How to Read the Result

The pace result is shown in minutes per kilometer. For example, 5.00 min/km means you take 5 minutes to cover each kilometer. The speed result is in kilometers per hour. A pace of 5.00 min/km corresponds to 12 km/h. If you run on a treadmill or track, you can compare your outdoor pace to the treadmill speed setting. Note that the calculator assumes a constant speed; real runs have hills, stops, and changes in pace, so the result is an average.

Common Mistakes

  • Mixing units: If you measure distance in miles, convert to kilometers first (1 mile = 1.60934 km). The calculator only works with kilometers.
  • Using seconds instead of minutes: If your finish time is 50 minutes and 30 seconds, convert to 50.5 minutes before entering.
  • Forgetting to convert time: If you enter time in hours (e.g., 1.5 hours), multiply by 60 to get minutes (90 minutes).

Limitations of the Formula

This formula gives an average pace and speed. It does not account for elevation gain, terrain, weather, or stops. For a more accurate training analysis, use a GPS watch or app that records splits. The formula is also linear: it assumes you maintain the same pace throughout, which is rarely true in practice. For interval training, calculate each interval separately.

Frequently Asked Questions

What is a good running pace for a beginner?

A beginner might run at 7:00 to 9:00 min/km (about 6.7 to 8.6 km/h). This varies widely with age, fitness, and gender. The key is to run at a conversational pace – you can talk without gasping.

How do I convert my pace from min/km to min/mile?

Multiply the pace in min/km by 1.60934. For example, 5.00 min/km × 1.60934 = 8.05 min/mile. Conversely, divide min/mile by 1.60934 to get min/km.

Does the calculator work for walking?

Yes, it works for any activity where you cover a distance over time. A typical walking pace is 12 to 15 min/km (4 to 5 km/h).

Why is my speed in km/h not a round number?

Because speed = distance / time, and time is not always a neat fraction of an hour. For example, 10 km in 45 minutes gives 13.33 km/h. That is normal.

Should I use pace or speed for training?

Most runners use pace (min/km) because it directly relates to effort per distance. Speed (km/h) is more common in cycling. Use whichever you find intuitive.

Related

Formula used
in t | Finish time | min | 50 | 0
in d | Distance | km | 10 | 0 | 100000
out pace | Average pace | min/km | t / d | 2
out speed | Average speed | km/h | d / (t / 60) | 2

Each line is one input (in, sel, list) or one result (out: label, unit, formula, decimals). How the calculators work

Method: the standard formula for this calculation, rounded as each result states. See how the calculators work or report an error.

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