Elapsed Time Calculator — Find the Duration Between Two Clock Times
Elapsed time is the total duration that passes between a start time and an end time. To calculate it, convert both times to minutes since midnight, subtract the start from the end, and convert back to hours and minutes. If the span crosses midnight, add 1,440 minutes (24 hours) to the end time before subtracting. This free calculator handles same-day, overnight, and multi-day elapsed time instantly.
Enter a start time and end time to instantly calculate the elapsed duration. This calculator supports AM/PM, 24-hour format, overnight spans, and optional date inputs for multi-day calculations.
Quick Reference: Common Elapsed Time Spans
| Start Time | End Time | Elapsed Time |
|---|---|---|
| 8:00 AM | 5:00 PM | 9h 0m |
| 9:00 AM | 5:00 PM | 8h 0m |
| 9:00 AM | 5:30 PM | 8h 30m |
| 7:00 AM | 3:30 PM | 8h 30m |
| 6:00 AM | 2:30 PM | 8h 30m |
| 10:00 PM | 6:00 AM | 8h 0m |
| 11:00 PM | 7:00 AM | 8h 0m |
| 10:00 PM | 6:30 AM | 8h 30m |
| 8:00 AM | 12:00 PM | 4h 0m |
| 1:00 PM | 5:00 PM | 4h 0m |
Calculate Elapsed Time
What Is Elapsed Time and How Is It Different From a Duration?
Definition: Elapsed time is the amount of time that passes between two specific clock readings. It answers the question "how long did it take?" by measuring the gap from a start point to an end point on a clock or calendar.
Elapsed time and duration are closely related but conceptually distinct. Elapsed time always references two fixed moments — a start and an end — on a clock or calendar. When you ask "How long was my flight from New York to London?", you are asking about elapsed time between takeoff and landing.
Duration, on the other hand, is a standalone length of time that is not anchored to specific clock readings. When a recipe says "bake for 45 minutes," that 45-minute span is a duration. It does not refer to any particular moment on a clock.
Key Takeaway: In practice, the result of calculating elapsed time is a duration. The distinction matters when building formulas or writing software: elapsed time requires two time-of-day inputs, while a duration stands alone. The ISO 8601 standard distinguishes between "time intervals" (elapsed time) and "durations" using separate notation formats.
How Do You Calculate Elapsed Time Step by Step?
Every elapsed time calculation follows the same core logic: convert both the start and end times into a common unit (minutes since midnight is simplest), subtract the start from the end, and then convert the result back into hours and minutes. Below are three worked examples covering the most common scenarios.
Same-Day Example: 9:15 AM to 4:30 PM
9:15 AM → 4:30 PM
555 min990 min435 minOvernight Example: 10:00 PM to 6:30 AM
10:00 PM → 6:30 AM (next day)
1,320 min390 min1,830 min510 minMulti-Day Example: Jan 3 at 2:00 PM to Jan 5 at 10:00 AM
January 3, 2:00 PM → January 5, 10:00 AM
840 min600 min2,640 minFor a deeper explanation of how base-60 arithmetic works, see our guide to time addition formulas. If you need to add multiple durations together — for example, totaling shift lengths across a week — use the time addition calculator instead.
How Does This Calculator Handle Overnight Time Spans?
The most common source of error in elapsed time calculations is the midnight crossover. When the end time is numerically smaller than the start time — say, starting at 11:00 PM and ending at 2:00 AM — a naive subtraction produces a negative number. The calculator detects this and adds 24 hours (1,440 minutes) to the end time before subtracting.
How the +24 hour technique works: If the end time in minutes since midnight is less than the start time, the span must cross midnight. Adding 1,440 minutes (one full day) to the end value places it on the "next day" timeline, making the subtraction straightforward. For example, 11:00 PM (1,380 min) to 2:00 AM (120 min): since 120 < 1,380, compute (120 + 1,440) − 1,380 = 180 minutes = 3 hours.
This calculator offers two ways to handle overnight spans. By default, it auto-detects: if the end time is earlier than the start time, it assumes you crossed midnight. You can also manually check the "End time is the next day" box to force overnight mode, which is useful when both times happen to be in the AM but span midnight (for example, 12:30 AM start to 4:00 AM end where you actually mean the following 4:00 AM).
For spans longer than 24 hours, use the date inputs. Entering specific calendar dates eliminates ambiguity and allows the calculator to handle multi-day durations precisely.
When Do You Need an Elapsed Time Calculator?
Elapsed time calculations arise in many everyday and professional scenarios. Below are five common situations where this calculator saves time and eliminates mental math errors.
Flight Duration
Calculate actual flight time from departure to arrival, including overnight red-eye flights that cross time zones and date boundaries.
Shift Length
Determine total hours worked for a shift, especially for overnight workers, nurses, and security staff whose shifts cross midnight. Pair with the work hours calculator for break deductions.
Event Timing
Plan conferences, meetings, or events by calculating exact durations between scheduled start and end times across single or multiple days.
Cooking & Baking
Track cooking processes that start at one time and finish hours later, such as slow-cooking, bread proofing, or multi-stage recipes that span overnight.
Sports & Fitness Timing
Calculate elapsed time for races, training sessions, and endurance events. Useful for marathon splits, cycling stages, and multi-lap timing.
Freelance Billing
Track billable hours between start and stop times for invoicing clients. Convert results to decimal hours for straightforward rate calculations.
Elapsed Time vs. Time Addition vs. Time Subtraction: How Do They Compare?
These three operations are related but serve different purposes. Understanding when to use each one helps you pick the right tool for the job.
| Operation | Input | Output | Use When… |
|---|---|---|---|
| Elapsed Time | Start time + End time | Duration (HH:MM) | You know two clock readings and need the gap between them |
| Time Addition | Multiple durations | Total duration (HH:MM) | You need to sum several time segments (e.g., weekly work hours) |
| Time Subtraction | Duration − Duration | Remaining duration | You need to find the difference between two durations (e.g., deducting break time from total hours) |
In many payroll workflows, all three are used together: elapsed time calculates each shift's raw hours, time subtraction removes unpaid break periods, and time addition totals the week's net hours. For a complete walkthrough, see our guide to calculating work hours.
Frequently Asked Questions About Elapsed Time
From 8:00 AM to 5:00 PM is exactly 9 hours. In 24-hour format, that is 08:00 to 17:00. Subtract 8 from 17 to get 9. If you need to account for an unpaid lunch break, use the work hours calculator to deduct that time automatically.
When the end time is earlier than the start time (numerically), the span crosses midnight. Add 24 hours (1,440 minutes) to the end time, then subtract normally. For example, 10:00 PM to 6:00 AM: convert to minutes since midnight (1,320 and 360), add 1,440 to the end (1,800), and subtract: 1,800 − 1,320 = 480 minutes = 8 hours. This calculator performs this adjustment automatically.
Elapsed time measures the gap between two specific clock readings — for example, from 2:15 PM to 5:45 PM. Duration is a standalone length of time (for example, 3 hours 30 minutes) that is not tied to any particular clock reading. When you calculate elapsed time, the result is a duration. The ISO 8601 standard uses different notation for each: time intervals use start/end timestamps separated by a slash, while durations use the "P" prefix format (e.g., PT3H30M).
From 10:00 PM to 6:00 AM is 8 hours. This is an overnight span that crosses midnight. In 24-hour notation: 22:00 to 06:00. Since 6 is less than 22, add 24 to get 30, then subtract: 30 − 22 = 8 hours.
Yes. Click "Add Dates for Multi-Day Calculation" in the calculator above and enter the start and end dates alongside the times. The calculator determines the number of complete 24-hour periods between the dates, then adds the remaining time difference. For example, January 3 at 2:00 PM to January 5 at 10:00 AM equals 44 total hours (1 day and 20 hours).
In Excel, enter the start time in cell A1 and the end time in cell B1 using a recognized time format (e.g., 9:15 AM). Use the formula =B1-A1 and format the result cell as [h]:mm:ss. For overnight spans where B1 is less than A1, use =B1-A1+(B1<A1) — the comparison (B1<A1) evaluates to 1 (representing one full day in Excel) when the end time is earlier than the start time.
This calculator computes elapsed time based on the clock values you enter. It does not automatically adjust for daylight saving time (DST) transitions. During a spring-forward event, the actual elapsed time is one hour less than the clock difference; during a fall-back event, it is one hour more. If your calculation spans a DST change, adjust the result by one hour accordingly. The NIST Time and Frequency Division maintains authoritative references on U.S. time standards and DST rules.
Payroll systems calculate elapsed time between clock-in and clock-out to determine raw hours worked. The result is typically converted to decimal hours for wage calculations — for example, 7 hours and 30 minutes becomes 7.50 hours. Under the Fair Labor Standards Act (FLSA), employers are permitted to round employee clock times to the nearest 5, 6, or 15 minutes under 29 CFR § 785.48(b), provided the rounding practice averages out over time and does not systematically shortchange employees. For a full breakdown, see our timesheet calculator.
The formula for elapsed time is: Elapsed Time = End Time − Start Time. Convert both times to minutes since midnight first. Multiply hours by 60 and add minutes (for example, 3:45 PM = 15 × 60 + 45 = 945 minutes). Subtract the start total from the end total. If the result is negative, add 1,440 (24 hours in minutes) to account for an overnight span. Divide the final result by 60 to convert back to hours and minutes.
To convert elapsed time to decimal hours, divide the minutes portion by 60 and add it to the whole hours. For example, 7 hours 45 minutes: divide 45 by 60 to get 0.75, then add to 7 for a total of 7.75 decimal hours. Common conversions include 15 minutes = 0.25, 30 minutes = 0.50, and 45 minutes = 0.75. Decimal hours are used in payroll, billing, and project tracking because they simplify multiplication with hourly rates.
A standard 8-hour work day contains 480 minutes (8 × 60 = 480). A 40-hour work week totals 2,400 minutes. If your work day includes an unpaid 30-minute lunch break, the elapsed time from clock-in to clock-out is 8.5 hours (510 minutes) even though only 8 hours (480 minutes) count as paid time. Use the work hours calculator to automatically subtract break periods from your total.
Open this elapsed time calculator in any mobile browser — it works on both iPhone and Android with no app download required. Enter your start and end times using the number inputs, select AM or PM, and tap "Calculate Elapsed Time." The result appears instantly in hours and minutes, decimal hours, and total minutes. For overnight spans, check the "next day" box before calculating.
Looking for a Different Time Calculator?
Time Addition Calculator
Add multiple time values together instantly.
Work Hours Calculator
Calculate hours worked with break deductions.
Timesheet Calculator
Build a full weekly timesheet with totals.
Time Subtraction Calculator
Subtract one time duration from another.
Overtime Calculator
Calculate overtime pay at 1.5× and 2× rates.
How Do We Ensure This Calculator Is Accurate?
Every formula on this page is verified against the time-interval definitions in the ISO 8601 international standard for date and time representation. Overnight and multi-day logic is tested with boundary cases (midnight crossover, same-time start/end, leap-day spans) and cross-checked against the base-60 arithmetic rules documented by the NIST Time and Frequency Division. Payroll-related content references the Electronic Code of Federal Regulations (29 CFR § 785.48) directly, not secondary summaries.
Last updated: February 7, 2026