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平均速度 電卓

速度、距離、時間を正確に計算する最速の方法。

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Average Speed Definition

Average speed equals the total distance traveled divided by the total time taken to cover that distance. The Average Speed Calculator computes this value in miles per hour (mph), kilometers per hour (km/h), meters per second (m/s), and feet per second (ft/s).

Average speed is a scalar quantity — it has magnitude but no direction. A car that drives 200 miles (321.9 km) in 4 hours has an average speed of 50 mph (80.5 km/h), regardless of the route taken or direction changes during the trip.

The Speed Distance Time Calculator uses 3 variables: speed, distance, and time. Knowing any 2 of these values lets you calculate the third using the average speed formula.

Build the Definition

Click the correct terms to complete the formula

Average Speed =
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Average Speed Formula

The Average Speed formula is Speed = Distance / Time (s = d/t)。この式には、unkn独自の変数を解決する 3 つの再配置があります。

  1. s = d / t — speed equals distance divided by time
  2. d = s × t — distance equals speed times time
  3. t = d / s — time equals distance divided by speed

The output unit depends on the input units. Distance in miles and time in hours produces miles per hour (mph). Distance in kilometers and time in hours gives kilometers per hour (km/h). Distance in meters and time in seconds yields meters per second (m/s).

Formula Triangle

Click any variable to see its formula

D S T DISTANCE SPEED TIME
Click a variable above

How to Calculate Average Speed

To calculate the average speed, follow these 3 steps:

  • Step 1: Measure the total distance traveled in miles, kilometers, or meters. Use a car's odometer, Google Maps, or a GPS device to record the distance.
  • Step 2: Record the total time taken in hours, minutes, or seconds. Subtract any rest stops from the total trip duration to get actual travel time.
  • Step 3: Divide distance by time 次の式を使用します。 速度 = 距離 / 時間 (s = d/t) .

Example: A car covers 250 miles (402.3 km) in 5 hours. Average speed = 250 / 5 = 50 mph (80.5 km/h).

For trips with stops, subtract idle time. A bus travels 180 miles (289.7 km) in 4 hours with 30 minutes of stops. Travel time = 3.5 hours. Average speed = 180 / 3.5 = 51.4 mph (82.8 km/h).

Step-by-Step Walkthrough

Click each step to complete it

1
Measure distance: 250 miles (402.3 km)
2
Record time: 5 hours (no stops)
3
Calculate: 250 ÷ 5 = 50 mph (80.5 km/h)

How to Use this Average Speed Calculator

To use this Average Speed Calculator, follow 3 steps:

  • Step 1: Select the calculation mode — choose Speed, Distance, or Time from the mode selector at the top of the calculator.
  • Step 2: Enter known values into the distance input and time input fields. Select the measurement units from the dropdown menus (miles, kilometers, meters, hours, minutes, seconds).
  • Step 3: Click the calculate button to view results in the result display area. The calculator shows the answer with a step-by-step formula breakdown and automatic unit conversions.

The Average Speed Calculator supports input in hh:mm:ss format and converts between mph, km/h, m/s, and ft/s automatically.

Calculator Guide

Click each step to walk through the process

1
Select mode: Speed / Distance / Time
2
Enter values: Distance = 120 mi, Time = 2 hr
3
Result: 60 mph (96.6 km/h)

Average Speed Calculator With Distance and Time

距離と時間を含む平均速度を計算するには、合計移動距離と移動時間を速度距離時間計算ツールに入力します。式 速度 = 距離 / 時間 (s = d/t) 結果が生まれます。

Example 1: A cyclist rides 30 miles (48.3 km) in 2 hours. Average speed = 30 / 2 = 15 mph (24.1 km/h).

Example 2: A train covers 200 kilometers (124.3 miles) in 2.5 hours. Average speed = 200 / 2.5 = 80 km/h (49.7 mph).

The Average Speed Calculator accepts distance in miles, kilometers, or meters and time in hours, minutes, or seconds. The formula engine handles all unit conversions automatically.

Quick Speed Calculator

Enter distance and time to calculate speed

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Average Speed Calculator Without Time

To find travel time without knowing time directly, rearrange the average speed formula to 時間 = 距離 / 速度 (t = d/s) . Enter the known distance and speed values to compute travel time.

To find distance when distance is unknown, use distance = speed × time (d = s × t) .

Example: A bus travels 120 miles (193.1 km) at an average speed of 40 mph (64.4 km/h). Time = 120 / 40 = 3 hours.

This rearrangement is useful for trip planning — enter the distance from Google Maps and the expected average speed to estimate the total trip duration before departure.

Time Finder

Adjust distance and speed to compute travel time

Time = 2.50 hours (2h 30m)

Average Speed Calculator for Multiple Speeds

The correct method to calculate average speed for equal distances at different speeds is the harmonic mean, not the arithmetic mean. The arithmetic mean gives an incorrect result because the object spends more time at the slower speed.

Average Speed = 2 × (S₁ × S₂) / (S₁ + S₂)

Example: A car drives 60 mph (96.6 km/h) for the first half and 40 mph (64.4 km/h) for the second half of an equal-distance trip. The arithmetic mean = 50 mph (wrong). The harmonic mean = 2 × (60 × 40) / (60 + 40) = 48 mph (77.2 km/h) (correct).

The harmonic mean produces a lower value than the arithmetic mean because the vehicle spends more time traveling at the slower speed, which pulls the average speed calculation down.

Harmonic Mean Calculator

Enter 2 speeds for equal distances — see correct vs incorrect average

✗ Arithmetic Mean (Wrong)
50.00 mph
✓ Harmonic Mean (Correct)
48.00 mph

Average Speed Calculator with Hours and Minutes

Convert time in hours, minutes, and seconds (hh:mm:ss) to decimal hours before applying the Average Speed formula. The conversion formula:

Decimal Hours = Hours + (Minutes / 60) + (Seconds / 3600)

Example: 2 hours 30 minutes 45 seconds = 2 + (30/60) + (45/3600) = 2 + 0.5 + 0.0125 = 2.5125 hours.

A trip of 150 miles (241.4 km) in 2 hours 30 minutes 45 seconds = 150 / 2.5125 = 59.7 mph (96.1 km/h).

The Average Speed Calculator accepts time in hh:mm:ss format directly and converts to decimal hours automatically.

Time Format Converter

Enter hours, minutes, seconds to get decimal hours

Decimal Hours 2.5125 hours

Average Speed Calculator for Multiple Legs

For trips with multiple legs, add the total distance traveled across all segments and divide by the total time taken. Each leg may have a different speed and distance across varying terrain types.

Example: A delivery van completes 3 legs:

  • 区間 1: 2 時間で 120 マイル (193.1 km) = 60 mph
  • 区間 2: 1.5 時間で 90 マイル (144.8 km) = 60 mph
  • 区間 3: 1 時間で 60 マイル (96.6 km) = 60 mph

Total distance = 270 miles (434.5 km). Total time = 4.5 hours. Average speed = 270 / 4.5 = 60 mph (96.6 km/h).

This method applies for last-mile delivery vans, bicycle courier routes, and any multi-segment journey with stops.

Multi-Leg Calculator

Enter distance and time per leg — totals update live

Leg Distance (mi) Time (hrs) Speed (mph)
Leg 1 60.0
Leg 2 60.0
Leg 3 60.0
Total 270.0 4.50 60.00

Units of Average Speed

Average speed uses distance-per-time units. The 4 most common units are:

  • 1. Miles per hour (mph) — used in the United States and United Kingdom for road speed
  • 2. Kilometers per hour (km/h) — used in most countries worldwide for automotive speed
  • 3. Meters per second (m/s) — the SI base unit for speed, used in scientific contexts
  • 4. Feet per second (ft/s) — used in engineering and some physics applications

Conversion factors: 1 mph = 1.60934 km/h = 0.44704 m/s = 1.46667 ft/s. The metric unit of speed in the International System of Units (SI) is meters per second (m/s).

Live Unit Converter

Enter a speed value and select the input unit

60.000 mph
96.561 km/h
26.822 m/s
88.000 ft/s

Average Speed vs. Average Velocity

Average speed is a scalar quantity — it equals total distance traveled divided by total time taken and has no direction. Average velocity is a vector quantity — it equals total displacement divided by total time and includes direction.

For a round trip with the same start and end point, average speed is greater than zero because total distance traveled is always positive. Average velocity for a round trip equals zero because displacement (net change in position) equals zero.

Example: A car drives 100 miles (160.9 km) east and returns 100 miles west in 4 hours total. Total distance = 200 miles (321.9 km). Displacement = 0 miles. Average speed = 200 / 4 = 50 mph. Average velocity = 0 / 4 = 0 mph. Use the Displacement Calculator to find displacement for specific paths.

Average Speed

Scalar quantity (magnitude only)

= Total Distance / Time

Always ≥ 0

Round trip: 50 mph

VS
Average Velocity

Vector quantity (magnitude + direction)

= Displacement / Time

Can be zero or negative

Round trip: 0 mph

往復パス

ドットが往復するのを観察してください。距離が増加し、変位がゼロに戻ります。

開始/終了 折り返し点

Average Speed vs Instantaneous Speed

Average speed covers the entire trip — total distance traveled divided by total time taken. Instantaneous speed is the speed at one specific moment, displayed on a speedometer or GPS device.

A car's speedometer shows instantaneous speed, which changes constantly during a trip. Average speed smooths all these speed variations into a single value for the entire journey.

Example: A car trip shows speedometer readings between 30 mph (48.3 km/h) and 70 mph (112.7 km/h) at various moments during peak congestion periods and highway stretches. The average speed for the entire 120-mile (193.1 km) trip over 2 hours = 60 mph (96.6 km/h).

Speedometer Comparison

Average stays constant while instantaneous fluctuates

0102030405060708090100
平均: 安定
0102030405060708090100
瞬時: 変動

Average Speed Vs Constant Speed

Constant speed means an object covers equal distances in equal time intervals throughout the journey. Average speed equals total distance traveled divided by total time taken over the entire trip.

When an object moves at constant speed, average speed equals that constant speed. When speed varies — due to acceleration, deceleration, or stops — average speed differs from the speed at any given moment.

Example 1: A car using cruise control at 60 mph (96.6 km/h) on a highway has both a constant speed and an average speed of 60 mph.

Example 2: A car in city traffic varies between 0 mph and 45 mph (72.4 km/h) during school zone hours and peak congestion periods, with an average speed of 25 mph (40.2 km/h).

Constant vs Varying Speed

Both dots finish at the same time — same average speed, different patterns

Constant
Varying

Average Speed from Speed-Time Graph

The area under a speed-time graph represents total distance traveled. To find average speed from a speed-time graph, follow 3 steps:

  1. Calculate the total area under the speed curve using geometric shapes (rectangles, triangles, trapezoids).
  2. Read the total time from the horizontal axis (start to end).
  3. Divide total area by total time: Average Speed = Total Area / Total Time.

For a rectangular region at constant speed, area = speed × time. For a triangular region with uniform acceleration from zero, area = ½ × base × height.

Speed-Time Graph

The shaded area equals total distance traveled

Average Speed from Velocity-Time Graph

A velocity-time graph shows velocity (speed with direction) over time. The area under the curve represents displacement, not total distance.

  1. Areas above the time axis indicate positive displacement (forward movement).
  2. Areas below the time axis indicate negative displacement (backward movement).

To find total distance from a velocity-time graph, sum the absolute values of all areas. Average speed = total distance / total time. Average velocity = net displacement / total time.

Velocity-Time Graph

Blue area = forward distance, Red area = backward distance

Common Mistakes When Calculating Average Speed

There are 5 common mistakes when calculating average speed. Click each card below to see the explanation and how to avoid the error.

Common Error
Using Arithmetic Mean Instead of Harmonic Mean
等しい距離で異なる速度の平均速度を計算する場合、算術平均では誤った結果が得られます。調和平均を使用します。 平均速度 = 2 x (S1 x S2) / (S1 + S2) 。車両は低速でより多くの時間を費やすため、真の平均は単純平均を下回ります。
クリックして表示 ->
Common Error
Forgetting to Subtract Rest Stops
Average speed uses actual travel time, not total elapsed time. Subtract rest stops, refueling breaks, and idle time from the total trip duration before dividing. A 5-hour trip with 1 hour of stops has 4 hours of travel time.
クリックして表示 ->
Common Error
Mixing Units Without Converting
Distance in miles with time in minutes produces an incorrect result unless converted. Convert minutes to hours (divide by 60), or kilometers to miles (multiply by 0.621371), before applying the formula speed = distance / time.
クリックして表示 ->
Common Error
Confusing Speed with Velocity
平均速度は合計距離 (スカラー、常に正) を使用します。平均速度は変位 (ベクトル、往復の場合はゼロになる可能性があります) を使用します。往路を 160 マイル、復路を 160 マイル走行する車の平均速度は > 0 ですが、平均速度 = 0 になります。
クリックして表示 ->
Common Error
Using Instantaneous Readings for Average
A speedometer or GPS shows instantaneous speed at one moment, not average speed. Average speed requires total distance traveled divided by total time taken. Instantaneous speed readings during peak congestion periods or highway stretches do not represent the overall average.
クリックして表示 ->

Average Speed Examples and Practice Questions

Practice these 5 average speed calculation problems. Click "Show Solution" to see the step-by-step answer for each question.

Q1: A runner covers 10 km (6.21 miles) in 50 minutes. Calculate the runner's average speed in km/h and mph.

Step 1: Convert time: 50 minutes = 50 / 60 = 0.833 hours.

Step 2: Apply formula: Speed = Distance / Time = 10 / 0.833 = 12.0 km/h.

Step 3: Convert: 12.0 km/h × 0.621371 = 7.46 mph.

Q2: A car travels 180 miles (289.7 km) in 3 hours 15 minutes. Find the average speed in mph.

Step 1: Convert time: 3h 15m = 3 + (15/60) = 3.25 hours.

Step 2: Apply formula: Speed = 180 / 3.25 = 55.38 mph (89.13 km/h).

Q3: A cyclist rides 25 km (15.53 miles) at 20 km/h, then 25 km at 30 km/h. Calculate the average speed for the entire trip.

Step 1: Time for leg 1: 25 / 20 = 1.25 hours.

Step 2: Time for leg 2: 25 / 30 = 0.833 hours.

Step 3: Total distance = 50 km. Total time = 2.083 hours.

Step 4: Average speed = 50 / 2.083 = 24.0 km/h (14.91 mph). Note: the answer is NOT 25 km/h (the arithmetic mean).

Q4: A train departs at 9:00 AM and arrives at 11:45 AM, covering 330 km (205 miles). Find the average speed.

Step 1: Calculate time: 11:45 - 9:00 = 2 hours 45 minutes = 2.75 hours.

Step 2: Apply formula: Speed = 330 / 2.75 = 120 km/h (74.56 mph).

Q5: A car drives 60 km at 40 km/h and returns at 60 km/h. Find the average speed for the round trip.

Step 1: Time going: 60 / 40 = 1.5 hours.

Step 2: Time returning: 60 / 60 = 1.0 hours.

Step 3: Total distance = 120 km. Total time = 2.5 hours.

Step 4: Average speed = 120 / 2.5 = 48 km/h (29.83 mph). The harmonic mean gives the correct answer for equal-distance round trips.

その他の平均速度計算機

Average Speed Calculator シリーズは、サイクリングやハイキングから、気体分子物理学、軌道力学、ブロードバンド テスト、読書のペースに至るまで、遭遇する可能性のあるあらゆる速度の問題をカバーします。以下の各計算機は、独自の数式、入力、インタラクティブな視覚化を備え、シナリオ専用に構築されています。

よくある質問

総移動距離と総所要時間は、平均速度を計算するために必要な 2 つの測定値です。速度 = 距離 / 時間 (s = d/t) の公式は、これら 2 つの値を使用して、時速マイル (mph)、時速キロメートル (km/h)、または秒当たりメートル (m/s) で結果を生成します。

特定の時間間隔中に移動した距離を測定し、経過時間で割ります。インターバルの平均速度 = インターバル距離 / インターバル時間。これにより、そのセグメントのみの平均移動率が得られます。

いいえ、平均速度は常にゼロまたは正です。平均速度は、合計距離 (常に正) を合計時間 (常に正) で割ったスカラー量です。速度には方向が含まれるため、平均速度が負になる場合があります。

ランニングの適切な平均速度は、初心者の場合は 5 mph (8 km/h)、中級ランナーの場合は 6 ~ 8 mph (9.7 ~ 12.9 km/h) の範囲です。エリートマラソンランナーは 12-13 mph (19.3-20.9 km/h) を維持します。ランニング速度計算機または GPS デバイスを使用して、マラソンのペーシング戦略中にランニング ペースを追跡します。

サイクリングの適切な平均速度は、カジュアルライダーの場合は 12-15 mph (19.3-24.1 km/h)、通常のサイクリストの場合は 15-20 mph (24.1-32.2 km/h)、競技者の場合は 20-28 mph (32.2-45.1 km/h) です。サイクリスト。速度はギア比の調整、タイヤの空気圧、地形の種類によって異なります。

すべてのセグメントの合計移動距離を加算します。停車に費やした時間を除く、停車地間の合計移動時間を加算します。総距離を総移動時間で割ります: 平均速度 = 総距離 / 総移動時間。

はい、式を時間 = 距離 / 速度 (t = d/s) に並べ替えます。距離と平均速度を平均速度計算ツールに入力して、移動時間を時間、分、または hh:mm:ss 形式で計算します。

いいえ、平均速度と平均速度は別の量です。平均速度は総移動距離を使用します (スカラー、常に >= 0)。平均速度は変位 (方向を含むベクトル、往復の場合は 0 にすることができます) を使用します。速度ベースの計算には Displacement Calculator を使用します。

距離をキロメートル、時間を時間を時間で測定し、平均速度 (km/h) = 距離 (km) / 時間 (時間) で割ります。例: 2 時間で 150 km = 75 km/h (46.6 mph)。 1.60934 を乗算して mph を km/h に変換します。

距離をマイル、時間を時間で測定し、平均速度 (mph) = 距離 (マイル) / 時間 (時間) で割ります。例: 2 時間で 120 マイル = 60 mph (96.6 km/h)。 0.621371 を乗算して、km/h を mph に変換します。

はい、平均速度がゼロになるのは、移動距離の合計がゼロに等しい場合、つまりオブジェクトがまったく移動していない場合のみです。合計距離が正であるため、開始点に戻る場合でも、あらゆる動作の平均速度は 0 より大きくなります。

両方向の距離を加算して合計距離を取得します。両方向の時間を加算して合計時間を取得します。合計距離を合計時間で割ります。 2 つの速度を算術的に平均しないでください。等しい距離の調和平均を使用します: Average Speed = 2 x (S1 x S2) / (S1 + S2)。

式を並べ替えて他の既知の値から距離を導き出し、速度 = 距離 / 時間を適用します。距離や速度の基準がなければ、平均速度は計算できません。3 つの変数 (速度、距離、時間) のうち少なくとも 2 つがわかっていなければなりません。

距離と時間のグラフの傾きは速度を表します。全行程の平均速度 = グラフ上の開始点から終了点までの総上昇 (距離の変化) / 総走行 (時間の変化)。傾きが急であればあるほど、速度が速いことを示します。

時間軸の下の面積の絶対値を使用して、速度-時間曲線の下の合計面積を計算します。合計距離 = すべての絶対領域の合計。平均速度 = 合計距離 / 合計時間。平均速度 = 正味変位 (上の領域から下の領域を差し引く) / 合計時間。

平均速度はスカラー量です。大きさ (mph や km/h などの単位を持つ数値) はありますが、方向はありません。平均速度は、大きさと方向の両方を含むベクトルに相当します。速度や距離などのスカラー量は、速度や変位などのベクトル量とは異なります。