If you are a freelancer, consultant, or agency owner billing by the hour, accurately tracking and converting your time is essential. A few minutes of unbilled time every day can add up to thousands of dollars in lost revenue over a year.
Converting Minutes to Decimal Hours
The most common mistake new freelancers make is billing standard minutes as decimals. For example, if you work for 1 hour and 30 minutes, you cannot bill your client for "1.30" hours. You must bill for "1.5" hours.
Because there are 60 minutes in an hour, you must divide your minutes by 60 to find the correct decimal.
The Decimal Conversion Formula
Minutes ÷ 60 = Decimal Hour
- 15 minutes ÷ 60 = 0.25 hours
- 30 minutes ÷ 60 = 0.50 hours
- 45 minutes ÷ 60 = 0.75 hours
Billing Increments
Most professionals do not bill by the exact minute (e.g., billing 0.116 hours for 7 minutes of work). Instead, they bill in standard increments. The two most common are:
- 15-Minute Increments: You round your time up to the nearest 15 minutes (0.25). If you work for 8 minutes, you bill for 15 (0.25). If you work for 20 minutes, you bill for 30 (0.50).
- 6-Minute Increments: This is standard in the legal profession. Because 6 divides perfectly into 60 ten times, every 6 minutes is exactly 0.1 hours. If a lawyer works for 10 minutes, they round up and bill for 12 minutes (0.2 hours).
Calculating Total Pay
Once you have your decimal hours, calculating your pay is incredibly simple. You multiply your Total Decimal Hours by your Hourly Rate.
If your rate is $75/hour, and you worked 3 hours and 45 minutes (3.75 hours):
3.75 × $75 = $281.25.
Tracking Project Profitability
Time tracking is not just for invoicing clients; it is critical for internal project management. If you quote a client a flat fee of $1,000 for a website, and you want to make $50/hour, you have a "budget" of 20 hours to complete the project.
If you track your time and realize the project actually took 30 hours, your effective hourly rate dropped to $33/hour ($1,000 ÷ 30). This tells you that your flat-fee pricing needs to be raised for future clients.
To quickly calculate the exact duration between a start and end time (e.g., starting work at 9:15 AM and finishing at 2:40 PM), you can use our Time Duration Calculator.