Time Duration Between Times Calculator

This calculator works out the time between a start and an end time in New Zealand, giving the result in hours and minutes and as decimal hours, and handling spans that run overnight. It answers a question that comes up constantly, from filling in a timesheet to working out how long a shift, a journey, a meeting or an event lasted, and doing it in your head is easy to get wrong, especially when the clock crosses midnight or noon. The method is simple once both times are turned into minutes from midnight: subtract the start from the end, and if the end is earlier than the start the period must run overnight, so a day is added. You enter the start time and the end time, and the calculator returns the duration in hours and minutes, and a decimal-hours figure, which is the form payroll and billing usually want. Use it for shift hours, to bill time, to check how long something took, or to total a block of the day. For pay, subtract any unpaid breaks from the result and then multiply the paid hours by your rate. Overnight shifts work correctly, so 10 pm to 6 am shows 8 hours, not a negative. A quick, reliable way to measure the time between two clock times.

8 h 30 min
duration between the times
Decimal hours8.50
Total minutes510

If the end time is before the start, the span is treated as overnight. Subtract unpaid breaks separately for paid hours. A timekeeping tool.

How it works

Both times are converted to minutes from midnight. The duration is the end minutes minus the start minutes; if that is negative, 1,440 minutes (a day) is added to handle an overnight span. The result is shown as hours and minutes, decimal hours, and total minutes.

Worked example

From 9:00 am to 5:30 pm is 510 minutes, which is 8 hours and 30 minutes, or 8.5 decimal hours. From 10:00 pm to 6:00 am, the overnight handling gives 8 hours.

Related calculators

If you've found a bug, or would like to contact us, or learn more about James Graham and Calculate.co.nz.

Calculate.co.nz is partnered with Interest.co.nz for New Zealand's highest quality calculators and financial analysis.

All calculators and tools are provided for educational and indicative purposes only and do not constitute financial advice.

Calculate.co.nz is proudly part of the Realtor.co.nz group, New Zealand's leading property transaction literacy platform, helping Kiwis understand the home buying and selling process from start to finish. Whether you're a first home buyer navigating your first property purchase, an investor evaluating your next acquisition, or a homeowner planning to sell, Realtor.co.nz provides clear, independent, and trustworthy guidance on every step of the New Zealand property transaction journey.

Calculate.co.nz is also partnered with Health Based Building and Premium Homes to promote informed choices that lead to better long-term outcomes for Kiwi households.

Calculate.co.nz is hosted in Auckland via SiteHost new Zealand.

All content on this website, including calculators, tools, source code, and design, is protected under the Copyright Act 1994 (New Zealand). No part of this site may be reproduced, copied, distributed, stored, or used in any form without prior written permission from the owner.

© 2019 to 2026 Calculate.co.nz. All rights reserved.