Travel Time Calculator

Distance {{ summaryDistance }} Stops {{ summaryStops }} Allowance {{ resultsReady ? `${computation.normalizedInputs.allowance_percent}%` : '—' }}

Departure date and time:

Date

Time

The calculator rejects local times skipped by a daylight-saving transition.

Departure time zone:

Examples: UTC, Asia/Kuala_Lumpur, Europe/London, or America/New_York.

Segment units:

The dense segment ledger uses one shared unit pair; mixed rows are intentionally avoided.

Travel segments:

Use expected average speed, not the speed limit. The final row's stop delays plan completion.

Segment	Distance ({{ profile.distanceUnit }})	Average speed ({{ profile.speedUnit }})	Stop after (min)	Remove
Label	Distance	Speed	Stop

Planning allowance:

Exact percentage

Tune from 0% to 200%, then compare the result with current route and operating conditions.

Repeated clock time:

The neutral default is earlier; this choice matters only during a repeated local clock hour.

Travel plan

{{ row.label }}{{ row.display }}

Departure: {{ departureLocal }}
Base arrival: {{ arrivalLocal }}
Planned arrival: {{ plannedArrivalLocal }}

Calculation method:

Segment time = distance ÷ average speed; stops are added; the allowance is applied once to that base duration.

planned = Σ(distance ÷ speed + stop) × (1 + allowance%)

{{ row.label }}{{ row.display }}{{ row.note }}

The chart renderer is unavailable. The same durations remain available in the travel plan and segment schedule.

Segment	Distance / speed	Moving	Stop	Arrival	Next departure	Copy
{{ row.label }}	{{ row.distance_speed }}	{{ row.moving }}	{{ row.stop }}	{{ row.arrival }}	{{ row.next_departure }}

Planning guide

Use average speed

Enter the pace you realistically expect across each segment, including ordinary slowdowns that are part of moving time—not the posted speed limit.

Separate known stops

Use stop minutes for planned breaks, transfers, charging, boarding, or other time when the journey is not moving.

Treat allowance as judgment

The allowance is a transparent user-entered buffer. It is not live traffic, a reliability percentile, or a promise of on-time arrival.

Check current conditions

Before travel, compare the plan with route, traffic, weather, timetable, vehicle, and applicable rest or operating requirements.

A useful arrival estimate starts with the speed that can actually be maintained over each part of a trip. Posted limits, peak speeds, and vehicle capability are not average travel speeds. Traffic, terrain, weather, loading, urban sections, and slow approaches can reduce the distance covered per hour even before planned stops are added.

Trips with different road, rail, air, or marine legs are clearer when split into segments. Each segment can have its own distance, expected average speed, and stop after arrival. The moving times are added first, followed by stop time. A planning allowance can then cover ordinary uncertainty without hiding which part of the estimate came from movement and which part came from delay.

An allowance is a percentage of the complete base duration, including entered stops. It is not a forecast of traffic or a guarantee of punctuality. A 20% allowance adds 12 minutes to a one-hour base trip and 36 minutes to a three-hour base trip, so the same percentage has a larger effect on longer plans.

Moving time is distance divided by expected average speed for each segment.
Base duration is total moving time plus all entered stops.
Planned duration is base duration plus the chosen allowance.
Estimated time of arrival adds elapsed duration to a specific departure instant.

Time zones matter when a trip crosses a clock change or when a local departure occurs near a daylight-saving transition. Some local clock times do not exist when clocks jump forward. Other clock times occur twice when clocks move back, so an earlier or later occurrence must be chosen to identify one real departure instant.

The result is a planning estimate rather than live routing. Road closures, congestion, security queues, rest requirements, weather, schedule changes, and border or terminal delays can move the actual arrival well beyond a simple distance-and-speed model.

How to Use This Tool:

Build the trip in the order traveled and use expected average speeds rather than legal or momentary maximums.

Set the departure date, local time, and an IANA time zone such as Asia/Kuala_Lumpur or Europe/London. If the local hour repeats during a clock change, choose the intended earlier or later occurrence.
Choose metric, imperial, or nautical segment units. Use one unit profile for all rows so distances and speeds remain comparable.
Enter each segment's distance, expected average speed, and stop minutes. Put a stop on the row after which it occurs; the final row's stop contributes to planned completion.
Set a planning allowance from 0% through 200%, then review moving time, stops, planned duration, and the segment schedule. Correct a zero speed, invalid zone, or skipped daylight-saving time before using the arrival estimate.

Interpreting Results:

Planned duration is the main buffered estimate. Compare it with Base duration to see exactly how much time the allowance adds. The unbuffered arrival follows the entered speeds and stops; the planned arrival also includes the allowance.

The segment schedule is most useful for spotting one optimistic assumption. A leg with a high average speed or a missing stop can dominate the error even when the total distance looks reasonable. Replacing that assumption is more informative than increasing the allowance until the arrival appears comfortable.

Use elapsed duration for the trip itself. Local clock labels may jump forward, repeat, or change offset across a daylight-saving transition.
Keep distance and speed in the selected paired units. Switching the unit profile converts both values so the physical travel time stays the same.
Recheck the plan against current route, operating, weather, and schedule information close to departure.

Technical Details:

Travel duration is accumulated as elapsed seconds. Metric rows use kilometers and kilometers per hour, imperial rows use miles and miles per hour, and nautical rows use nautical miles and knots. Each paired distance and speed unit produces hours directly; distances are also normalized to kilometers for the total-distance result.

Formula Core:

For segment distance d, average speed v, and stop minutes s, total moving and stop time are:

\begin{matrix} T_{move} & = & \sum_{i = 1}^{n} \frac{d_{i}}{v_{i}} \\ T_{stop} & = & \sum_{i = 1}^{n} s_{i} \times 60 \end{matrix}

The allowance is applied once to the base duration:

T_{planned} = (T_{move} + T_{stop}) (1 + \frac{a}{100})

a is the entered allowance percentage. The planned arrival instant equals the departure instant plus planned seconds. Results retain fractional seconds internally and are rounded to the nearest second for duration display.

For a 120 km segment at 80 km/h followed by 60 km at 60 km/h, moving time is 2.5 hours. A 15-minute stop makes the base duration 2 hours 45 minutes. A 10% allowance adds 16 minutes 30 seconds, producing a planned duration of 3 hours 1 minute 30 seconds.

Time-Zone Rule Core:

Travel time local clock resolution rules
Local-time condition	Rule
Ordinary local time	The named zone and local clock value resolve to one departure instant.
Skipped time	A local clock value with no matching instant during a forward jump is rejected.
Repeated time	The earlier matching instant is the default; the later occurrence can be selected explicitly.
Supported date range	Departure dates must resolve to an instant from 2000 through 2100.

Up to 12 segments are supported. Each distance must be greater than 0 and no more than 1,000,000 selected distance units; each speed must be greater than 0 and no more than 10,000 selected speed units; each stop may range from 0 through 1,440 minutes. Plans exceeding ten years of elapsed duration are rejected.

Accuracy Notes:

The calculation is deterministic for the entered assumptions, but those assumptions are not a route forecast.

Average speed must already reflect expected slow sections. The model does not infer acceleration, traffic, terrain, weather, or legal rest periods.
Entered stops are fixed durations. Queues, transfers, border checks, refueling, loading, and missed connections can vary independently.
Named-zone results depend on the time-zone data available to the browser. Governments can change future offsets or daylight-saving rules after a plan is made.

References:

Does Travel Time Reliability Matter? A Primer, Federal Highway Administration, October 2019.
Theory and pragmatics of the time zone database, Internet Assigned Numbers Authority.
ECMAScript Internationalization API Specification, Ecma International, 2027.