Billable Hours Calculator — Free Time Tracker
Track billable hours, calculate invoice amounts, multi-rate clients. Free, browser-only — no signup.
About BillableHours
A billable hours calculator tracks work time in fractional hours and computes the invoice amount. Useful for freelancers, lawyers, consultants — anyone billing by the hour. The ZTools Billable Hours tool offers two modes: a stopwatch (start / stop / pause) for live tracking, and a manual entry form for retroactive logging. Multiple rates per client / task, rounding rules (nearest 6 / 15 / 30 minutes), tax / discount, and CSV export of the time log.
Use cases
- Track hours for a client project. Stopwatch starts when you begin work, pauses for breaks, stops at end of day. Tool sums total billable hours.
- Calculate an invoice. Total hours × rate = invoice amount. Tool handles multi-rate (different tasks at different rates) and tax.
- Retroactive logging. Forgot to start the timer? Manually enter time blocks (start, end). Tool computes total.
- Compare planned vs actual. Estimated 40 hours; actual 47. Tool shows over/under.
How it works
- Add a task. Name, client, rate. Tool shows live timer or accepts manual time entry.
- Track time. Stopwatch with start / pause / stop. Multiple concurrent tasks if needed.
- Configure rounding. Lawyers often round to nearest 6 minutes (0.1 hour). Some round up to 15 minutes. Tool supports both.
- Export. CSV with task / client / hours / rate / amount. Plug into invoice software.
Examples
Input: 3.5 hours @ $100/hour
Output: $350 (with rounding off).
Input: Same time, rounded up to nearest 15 min
Output: 3.75 hours × $100 = $375.
Input: Multi-rate: 2 h research @ $80, 1.5 h drafting @ $120
Output: $160 + $180 = $340.
Frequently asked questions
Does it persist across sessions?
Tool uses localStorage (or @capacitor/preferences in mobile) — your data stays on the device. Closing the browser keeps logs; clearing browser data wipes them. Always export CSV regularly as backup.
How are partial hours rendered?
Decimal (3.5) by default. Toggle to show as HH:MM (3:30) for invoices that prefer that format.
Tax / discount handling?
Optional tax % applied to subtotal. Discounts are flat or percentage. Both shown in invoice export.
Multi-currency?
Pick currency per client. Tool tracks separately so cross-currency invoicing doesn't mix.
Privacy?
All client-side.
Pro tips
- Export CSV at the end of every week — protects against accidental browser data wipe.
- For lawyer billing, round to 6-minute increments (0.1 hour). Most legal billing systems expect this.
- For freelance work, track in 15-minute increments — simpler invoices.
- Tag time by task type when possible — easier to identify which projects are most profitable.
Reviewed by Ahsan Mahmood · Last updated 2026-05-06 · Part of ZTools.
For the full,
formatted version of this page, please enable JavaScript and reload
https://ztools.zaions.com/billable-hours.