About HowManyHoursIn
We are dedicated to making time calculations simple, accurate, and accessible for everyone. From students to professionals, our tools help people understand and manage time better.
Who runs this site
Darrell Donaghy
Founder · Minnesota, USA
Darrell Donaghy is an indie developer based in Minnesota who has been building web tools for 25 years. By day he's a Marketing Director with 15 years of experience. HowManyHoursIn.com is one of several side projects where he builds small, focused utilities he uses himself.
I built this site because I kept Googling questions like "how many work hours in a year" and getting either the wrong answer or a wall of cookie-banner spam. The goal here is simple: the right number, fast, with the math shown and the source cited. No signup, no paywall, no upsells.
The site is built with Next.js. Every formula is verified against primary sources — see the methodology page for the full list, including the SI second definition (BIPM), the U.S. work-year standard (FLSA), the Gregorian leap-year rules, and the IANA Time Zone Database.
Our Methodology & Sources
Every calculation and claim on this site is based on verifiable, authoritative sources. Here are the primary references we use:
Time Unit Definitions
Based on the International System of Units (SI). One second is defined as 9,192,631,770 periods of the cesium-133 atom. One hour = 3,600 seconds. One day = 86,400 seconds. Source: Bureau International des Poids et Mesures (BIPM).
Work Hour Standards
The 2,080-hour standard work year (52 weeks x 40 hours) is based on the U.S. Fair Labor Standards Act (29 U.S.C. 207). International work hour data is sourced from the OECD and International Labour Organization (ILO) databases.
Calendar & Leap Year Rules
Leap year calculations follow the Gregorian calendar rules established by Pope Gregory XIII in 1582: a year is a leap year if divisible by 4, except for century years which must be divisible by 400. This is the internationally accepted civil calendar standard.
Time Zone & DST Data
Time zone calculations use your browser's built-in Intl API, which follows the IANA Time Zone Database (tzdata), the global authority on time zone rules maintained by a community of volunteers and used by all major operating systems.
Our Editorial Standards
We hold ourselves to high standards for accuracy and usefulness. Here is how we ensure quality across our content:
Fact-Checking
Every statistic and claim is verified against primary sources. We cite our references and link to original research where applicable.
Regular Updates
We review and update our content periodically to ensure information remains current. This includes updating leap year calculations, reflecting changes in labor laws, and incorporating new research.
User Feedback
We actively incorporate user feedback to improve our tools and content. If you find an error or have a suggestion, we want to hear from you.
Transparency
We explain our methodology and are upfront about limitations. When calculations require assumptions (like average month length), we clearly state what those assumptions are.
Corrections Policy
We get things wrong sometimes. When we do, we want to know — and we fix it quickly and visibly.
- Report errors:Email hello@howmanyhoursin.com with the page URL and what is wrong.
- Response time:Verified factual errors are corrected within 7 days.
- Transparency:When we change a number or claim on a calculator page, we update the "Last reviewed" date at the top of that page.
See the methodology page for the full list of sources we verify against.
Our Mission
To make time calculations effortless for everyone.
We believe that understanding time should not require a calculator, spreadsheet, or complex mental math. Our mission is to provide instant, accurate time conversions and calculations, along with educational content that helps people truly understand time measurements and their practical applications.
Our Values
Accuracy First
Every calculation is verified and accurate. We account for leap years, varying month lengths, and different work standards across regions.
Simplicity
Time calculations should be straightforward. No complicated interfaces, no sign-ups required—just instant, clear answers.
Accessibility
Our tools are free and accessible to everyone. Whether you are a student, professional, or curious mind, we are here to help.
Educational Value
Beyond calculations, we provide context and explanations to help you understand time concepts better.
What We Offer
- Calculate hours in any time period (days, weeks, months, years)
- Work year calculations for different employment standards
- Time-ago calculators for quick reference
- Detailed breakdowns with practical examples
- Mobile-friendly design for on-the-go calculations
- No registration or personal data required
Our Commitment to Accuracy
Time calculations may seem straightforward, but accuracy matters. Here is how we ensure our calculations are reliable:
- Leap Years:We properly account for leap years (366 days = 8,784 hours) in all annual calculations.
- Month Variations:We provide calculations for all month lengths (28, 29, 30, and 31 days) and averages.
- Work Standards:We reference standard work week hours (typically 40 hours) used in most industries.
- Regular Updates:We review and update our content to ensure continued accuracy and relevance.
Note: While we strive for accuracy, our calculations are for informational purposes. For critical applications like payroll or legal deadlines, we recommend verification with relevant authorities.
Get in Touch
Have questions, suggestions, or feedback? We would love to hear from you. Your input helps us improve and create better tools for everyone.
Contact Us