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Time Tracker
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Billable
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Tracked time
Archived tasks
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| Task/Project | Mon | Tue | Wed | Thu | Fri | Sat | Sun | Total |
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Timesheet Export & Summary: Copy text breakdown or download CSV.
Time Economics & Billable Increment Mathematics
Professional consultants and legal agencies bill using discrete quantum increments rather than continuous wall-clock seconds. The two standard professional models are tenth-of-an-hour (6-minute blocks) and quarter-hour (15-minute blocks):
1. High-Precision Epoch Delta Calculation:
Δt = t_now - t_start (Using window.performance.now() or Date.now() to bypass background throttling)
2. 6-Minute Tenth-of-an-Hour Rounding:
Hours_billed = ⌈ Minutes / 6 ⌉ × 0.1 (e.g. 7 minutes → 0.2 hours)
3. Effective Realization Rate (ERR):
ERR = (Total Billed Revenue) / (Total Logged Hours [Billable + Administrative])
5 Fatal Traps in Freelance Time Tracking & Billing
1. The Background Tab Timer Throttling Trap
Relying on simple
setInterval(fn, 1000) counters. Modern Chromium and WebKit browsers automatically throttle background timer callbacks to once per minute (or suspend execution entirely) to conserve laptop battery. Trackers must calculate elapsed time via absolute timestamp subtraction (Date.now() - startTime).
2. The LocalStorage 5MB Eviction Trap
Storing endless uncompressed tracking events in browser
localStorage without export utilities. Once local storage exceeds 5MB, browser writes fail silently or trigger storage exceptions, risking sudden historical data loss during browser cache sweeps.
3. The Unrounded 6-Minute Increment Underbilling Trap
Billing clients by exact minute fractions (e.g. 17 minutes = 0.283 hours) instead of the industry-standard 6-minute (0.1 hr) or 15-minute (0.25 hr) minimum billing blocks. Micro-task switching friction erodes 15–20% of billable revenue if brief client calls are not rounded up.
4. The Daylight Saving Timestamp Glitch
Storing timestamps as local wall-clock strings like "2:30 AM" instead of UTC ISO-8601 strings. During autumn daylight saving transitions, the 1:00 AM to 2:00 AM hour repeats, causing trackers to record zero or negative elapsed time for overnight work sessions.
5. The Unassigned Context-Switching Leakage
Failing to log the 5-to-10 minute gap spent switching between client projects, finding files, or sending deliverables. Studies indicate knowledge workers lose over 2.1 hours per day to unrecorded micro-switching that never reaches client invoices.
Frequently Asked Questions
Does the time tracker keep running if I switch tabs or minimize the browser?
Yes. The timer calculates elapsed time based on real-world epoch timestamps (
Date.now()). Even if your browser suspends tab animation, the clock accurately computes the exact duration the moment you switch back.
Can I convert my tracked hours into a client invoice?
Yes! Use our companion tool, Invoice from Time, which reads your local tracked entries and generates a formatted invoice with rates and PDF printing.
Where is my timesheet data stored?
All project tags, time entries, and client rates are stored exclusively inside your browser's private
localStorage database. No tracking data is sent to external servers.
Can I export my time logs to CSV or Excel?
Yes. You can copy your timesheet summary or export entries to generate invoices and financial records with one click using the Export CSV button above.
What is the 6-minute billing increment rule?
Law firms and elite consulting agencies divide each hour into ten 6-minute blocks (0.1 hours). A task lasting 1 to 6 minutes is billed as 0.1 hr, while a 7-minute task is billed as 0.2 hr, ensuring fair compensation for overhead.
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