Calculate Hours Between Times
Enter a start and end time to get total hours in multiple formats.
How the Hours Calculator Works
Simple steps to calculate hours.
Enter Start Time
Set the starting time using the time picker. Any time from 00:00 to 23:59.
Enter End Time
Set the ending time. Overnight durations (end before start) are handled automatically.
Calculate
Click "Calculate Hours" and get instant results in HH:MM and decimal formats.
Use Results
Copy decimal hours for payroll or use HH:MM for scheduling. All formats available.
What Is an Hours Calculator?
Understanding time-to-hours conversion.
Hours calculation basics
An Hours Calculator converts the time span between two clock readings into a numeric value. The formula: Hours = (End Time − Start Time) ÷ 60 minutes.
The key output is decimal hours — the format used in payroll systems, billing software, and project management tools. 8 hours 30 minutes = 8.50 decimal hours.
Common decimal conversions
- 15 minutes = 0.25 hours
- 30 minutes = 0.50 hours
- 45 minutes = 0.75 hours
- 20 minutes = 0.33 hours
- 10 minutes = 0.17 hours
Overnight handling
If the end time is before the start time (e.g., 10 PM to 6 AM), the calculator adds 24 hours to produce the correct 8-hour result. Convert those hours into any other unit with the time units converter.
When to Use an Hours Calculator
Common hours calculation scenarios.
Payroll Processing
Convert clock-in/out times to decimal hours for payroll. Multiply by hourly rate for accurate compensation.
Client Billing
Track billable hours per client. Convert to decimal format for invoicing and accounting software.
Timesheet Entry
Fill in digital timesheets that require decimal hours. Avoid manual conversion errors.
Sports Timing
Convert race and workout durations to hours for pace calculations and training logs.
Study Tracking
Log study session hours in decimal format. Track total weekly study time easily.
Media Production
Calculate recording session length for audio and video projects. Budget studio time precisely.
Hours Calculation Examples
Common time-to-hours conversions.
Standard workday
9:00 AM → 5:30 PM = 8h 30m = 8.50 decimal hours = 510 minutes.
Half day
9:00 AM → 1:00 PM = 4h 00m = 4.00 decimal hours = 240 minutes.
Night shift
10:00 PM → 6:00 AM = 8h 00m = 8.00 decimal hours = 480 minutes.
Step-by-Step Walkthrough
Follow a single shift from two clock readings all the way to gross pay, one step at a time.
A support technician clocks in at 7:45 AM and clocks out at 4:20 PM. Their rate is $22.00 per hour. How many hours is that, and what does it pay?
Convert both clock times to minutes past midnight
7:45 AM → (7 × 60) + 45 = 465 4:20 PM → (16 × 60) + 20 = 980Clock time is base-60, so subtracting 4:20 − 7:45 directly invites borrowing errors. Flattening both readings into a single count of minutes removes the mixed base entirely.
Running total465 and 980 minutes
Subtract start from end
980 − 465 = 515 minutesOne plain subtraction now does the whole job. Because the end value is larger than the start value, this shift sits inside a single calendar day and needs no overnight adjustment.
Running total515 minutes
Split the minutes back into hours and minutes
515 ÷ 60 = 8 remainder 35The whole part is complete hours and the remainder is leftover minutes. This is the HH:MM form that rosters and schedules expect.
Running total8h 35m
Convert to decimal hours for payroll
35 ÷ 60 = 0.5833… → 8 + 0.58 = 8.58 hoursPayroll multiplies by an hourly rate, so it needs one decimal number rather than two mixed units. Only the minute portion is divided by 60 — the whole hours carry across untouched.
Running total8.58 decimal hours
Apply the hourly rate
8.58 × $22.00 = $188.76Multiplying the decimal figure gives correct gross pay. Multiplying the HH:MM figure instead — 8.35 × $22 — would quietly underpay by $5.06 for this one shift.
Running total$188.76 gross
A 7:45 AM to 4:20 PM shift is 8h 35m, 8.58 decimal hours, or 515 minutes. The decimal figure is the one payroll needs — and the one people most often get wrong.
Common Mistakes and Pro Tips
Mistakes that quietly corrupt your numbers
Reading 8h 35m as 8.35 hours and multiplying that by the pay rate.
Convert the minutes first: 35 ÷ 60 = 0.58, giving 8.58 hours.
Why it matters: HH:MM and decimal hours look almost identical but agree only at whole hours. The gap peaks near the half hour, where 8h 30m read as 8.30 loses 0.20 h — roughly 12 minutes of unpaid work on every shift.
Getting a negative or nonsensical total for a shift that ran 10:00 PM to 6:00 AM.
Add 24 hours when the end time is earlier than the start: (6:00 + 24h) − 22:00 = 8 hours.
Why it matters: A clock reading carries no date. Without the rollover, every night shift subtracts to −16 hours instead of +8 — a sign error that hides easily in a spreadsheet column of otherwise sensible numbers.
Rounding each day to the nearest quarter hour, then adding up the rounded days.
Sum the exact daily minutes first, then round the weekly total once.
Why it matters: Rounding compounds. Five days each nudged up by seven minutes silently adds 35 minutes nobody worked; rounded down, the same drift takes pay away. Rounding last keeps the error inside one interval.
Counting the unpaid lunch break because it sits between clock-in and clock-out.
Subtract unpaid break minutes from the span before converting to decimal hours.
Why it matters: A 9:00–17:30 span is 8.50 hours elapsed but only 7.75 payable once a 45-minute unpaid lunch comes out. Elapsed time and payable time are different quantities, and payroll wants the second.
Pro tips
Memorise the four anchors
Quarter-hour conversions cover most timesheets: 15 min = 0.25, 30 min = 0.50, 45 min = 0.75, 60 min = 1.00. Every other value sits between two anchors, which makes a wrong answer easy to spot at a glance.
Keep two decimal places
Twenty minutes is 0.3333… hours. Truncating to 0.33 is standard practice — but do it only on the final total. Rounding every row first is what produces those stubborn one-cent payroll discrepancies.
Flag night shifts explicitly
If your log mixes day and night shifts, add a column marking which ones cross midnight. It turns the +24 hour adjustment into something auditable rather than invisible.
Reconcile against the week
A full-time week should land near 40.00 hours. A weekly total ending in an odd fraction such as 39.85 usually points at one mistyped minute value rather than five slightly-off days.
Record the raw times too
Store clock-in and clock-out beside the computed hours. When a figure is queried months later the original readings settle it — a lone decimal total cannot be re-derived.
Match your employer’s interval
Some workplaces bill in tenths of an hour (6-minute blocks), others in quarters. Convert using the interval your contract names, because 0.1 h and 0.25 h round very differently from the same raw minutes.
Minutes to Decimal Hours Conversion Table
The complete five-minute lookup. Filter it to find any value instantly, or keep the tab open while you fill in a timesheet.
| Minutes | Exact decimal | Rounded (2 dp) | Share of an hour |
|---|---|---|---|
| 0 min | 0.0000 | 0.00 | — |
| 5 min | 0.0833 | 0.08 | 8% |
| 10 min | 0.1667 | 0.17 | 17% |
| 15 min | 0.2500 | 0.25 | 25% |
| 20 min | 0.3333 | 0.33 | 33% |
| 25 min | 0.4167 | 0.42 | 42% |
| 30 min | 0.5000 | 0.50 | 50% |
| 35 min | 0.5833 | 0.58 | 58% |
| 40 min | 0.6667 | 0.67 | 67% |
| 45 min | 0.7500 | 0.75 | 75% |
| 50 min | 0.8333 | 0.83 | 83% |
| 55 min | 0.9167 | 0.92 | 92% |
No rows match that filter.
Values ending in .3333 and .6667 repeat forever — 20 and 40 minutes have no exact decimal form. Round them at the final total only. For units larger than an hour, use the time units converter.
Going Deeper on Hours Calculation
The context behind the arithmetic — why the formats differ, and where the edge cases hide.
Why payroll uses decimal hours at all
Clock time is sexagesimal — it rolls over at 60, a convention inherited from Babylonian arithmetic. Money is decimal, rolling over at 10. Multiplying a base-60 quantity by a base-10 rate has no meaning until one of them is converted.
Decimal hours are that conversion. Once minutes become a fraction of an hour, hours × rate is ordinary multiplication, and every spreadsheet, payroll package and invoicing tool can handle it without special time logic.
That is also why the payroll hours calculator asks for a rate while the time difference calculator does not.
The rounding rules you are likely to meet
Three conventions dominate timesheets:
- Quarter-hour (15 min): the most common. Under the widely used seven-minute rule, 1–7 minutes past a quarter round down and 8–14 round up.
- Tenth-hour (6 min): standard in legal and agency billing, where 0.1 h is the smallest billable unit.
- Exact minutes: no rounding at all, increasingly normal with digital clock-in systems.
Rounding is only defensible when it is neutral over time — as likely to favour the worker as the employer. A policy that always rounds down is a pay cut wearing a maths costume.
When the two times sit in different zones
Subtracting clock readings assumes both came from the same clock. A call starting 9:00 in London and ending 11:30 in New York did not last 2h 30m.
Normalise both readings to a single zone — usually UTC — before subtracting. The time zone converter handles that conversion, after which the arithmetic on this page applies unchanged.
Daylight saving adds one more wrinkle: a shift crossing a spring-forward boundary is one hour shorter in elapsed time than its clock readings suggest, and one hour longer in autumn.
Checking a total without redoing the maths
Two quick sanity checks catch most errors:
- The whole-hour bound. The decimal result must sit between the whole hours and the next hour up. For 8h 35m, anything outside 8.00–9.00 is wrong.
- The halfway test. Minutes above 30 must give a decimal fraction above .50, and minutes below 30 must give below .50. This alone catches the 8.35-for-8h-35m mistake instantly.
For multi-day totals, compare against the expected weekly figure before accepting the number. Reconciliation beats recalculation.
Frequently Asked Questions
Common questions about the Hours Calculator.
How do I calculate hours between two times?
Enter a start time and end time. The calculator subtracts the start from the end and shows the result in hours and minutes (HH:MM), decimal hours, total minutes, and total seconds.
What are decimal hours?
Decimal hours express time as a decimal number. 7 hours 30 minutes = 7.50 decimal hours. 45 minutes = 0.75 hours. This format is standard for payroll, billing, and timesheets because it multiplies directly with hourly rates.
Does it handle overnight calculations?
Yes. If the end time is earlier than the start time (e.g., 10 PM to 6 AM), the calculator adds 24 hours to correctly compute the overnight duration as 8 hours.
Can I use this for payroll?
Absolutely. The decimal hours output is ready for payroll calculations. Multiply decimal hours by the hourly rate to get pay. 7.50 hours × $20/hr = $150.
How do I convert minutes to decimal hours?
Divide minutes by 60. For example: 15 min = 0.25 hrs, 30 min = 0.50 hrs, 45 min = 0.75 hrs, 20 min = 0.33 hrs. The calculator does this automatically.
Is this hours calculator free?
Yes, completely free with no sign-up. Every conversion runs in your browser, so the clock times you enter are never transmitted or stored anywhere.
Why does 8 hours 35 minutes show as 8.58 and not 8.35?
Because only the minutes are converted: 35 ÷ 60 = 0.58, so the total is 8.58 hours. Writing 8.35 would treat the minutes as hundredths of an hour instead of sixtieths, understating the shift by about 14 minutes.
Should I subtract unpaid breaks from the result?
Yes, if the break is unpaid. This calculator returns elapsed time between two clock readings, which includes any break sitting inside that span. Subtract unpaid break minutes to get payable hours, or use the break time calculator to do it automatically.
How many decimal places should I keep?
Two is the payroll standard. Round only at the final total rather than on each row, because rounding every entry first is what causes small but persistent differences between a timesheet and a pay slip.
Does the calculator handle shifts longer than 24 hours?
No. Two clock times can describe at most a 24-hour span, since neither reading carries a date. For longer periods use the date duration calculator, which takes full dates as well as times.