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How Freelancers Can Track Billable Hours

By Frame Sixty Labs · Last updated: August 24, 2026

Most advice about billable hours assumes you want software that watches you work. Plenty of freelancers do not: they work in long blocks, switch clients a couple of times a day, and need one honest number per client at the end of the week. This guide covers that workflow end to end — what to write down, how to total it without losing minutes, and how to turn the total into an invoice line you can defend.

What counts as a billable hour?

Decide this before you start logging, because retro-fitting the rule to a week you have already worked never feels honest. The usual split:

Two grey areas are worth naming in the contract rather than deciding week by week: travel time, and out-of-scope revisions. Both are common sources of an awkward conversation after the invoice lands.

What does a billable-hours workflow actually need?

Strip it back and there are only four requirements:

1. A start and stop time per session. Times, not durations — “09:15 to 12:00” can be checked later; “about three hours” cannot.
2. A client tag on every line. One log for everything is fine as long as each line says whose work it was.
3. Arithmetic that understands H:MM. Time is base 60. A calculator that treats 12:45 as 12.45 will quietly under-bill you.
4. A record that outlives the invoice. If a client queries a line six months later, you want the session list, not a memory.

A notebook covers the first two. The third is where the workflow usually breaks, and it is the reason a plain calculator is the wrong tool — a longer explanation lives in how to add hours and minutes.

How do you log a session without a running timer?

Write the stop time the moment you stop, not at the end of the day. That single habit removes almost all of the guesswork, and it costs about three seconds. A workable line looks like this:

Tue · Northgate · 08:40–11:55 · landing page copy

The note at the end matters more than it looks. It is what lets you answer “what was that 3:15 on Tuesday?” without reconstructing the week, and it is what turns a raw log into an invoice a client can read.

If you forget a stop time, do not guess generously. Bill the time you can defend — the shorter, safer figure — and fix the habit. A log that is known to be conservative is worth more in a dispute than one that is known to be approximate.

How do you total a week across two clients?

Here is a real-shaped freelance week: two clients, nine sessions, no round numbers. Northgate pays $85.00 an hour, Vela pays $70.00.

Take one duration slowly, because this is where minutes go missing. Tuesday morning runs 08:40 to 11:55. From 08:40 to 11:40 is three whole hours; 11:40 to 11:55 adds 15 minutes. The session is 3:15, not 3.15 and not 3:15 rounded to “about 3¼” — it is exactly three hours and fifteen minutes. Friday afternoon is the same idea in reverse: 13:00 to 14:55 is 1:55, five minutes short of two hours.

Now add each client, carrying 60 minutes into an hour whenever the minutes pass 59:

• Northgate: 2:45 + 3:15 = 6:00, + 1:20 = 7:20, + 3:30 = 10:50, + 1:55 = 12:45
• Vela: 3:15 + 3:15 = 6:30, + 2:15 = 8:45, + 1:45 = 10:30
• Week: 12:45 + 10:30 = 23:15 billable

That last carry is the one people get wrong: 10:50 + 1:55 means 50 + 55 = 105 minutes, which is 1 hour 45 minutes, so 10 + 1 hours plus 1:45 gives 12:45. Not 11:105, and not 12:105.

How do you turn the total into an invoice figure?

Invoices are priced in decimal hours, so convert before you multiply. Divide the minutes by 60 and add them to the hours:

• Northgate: 12:45 → 45 ÷ 60 = 0.75 → 12.75 hours × $85.00 = $1,083.75
• Vela: 10:30 → 30 ÷ 60 = 0.50 → 10.50 hours × $70.00 = $735.00
• Week: $1,083.75 + $735.00 = $1,818.75 across 23.25 hours

The expensive mistake is copying the minutes across the decimal point. Billing Northgate for 12.45 hours instead of 12.75 comes to $1,058.25 — $25.50 less, for 18 minutes you actually worked. Repeat that on every invoice and it is a meaningful part of a year. The full conversion is laid out in hours to decimal, and the pricing side in the hourly rate to pay guide.

Should you round billable time?

Rounding to 6-minute (0.1 hour) or 15-minute (0.25 hour) increments makes an invoice easier to read, and many clients expect it. What matters is that the rule is written in the contract and applied identically every time. Compare two rules against the same Northgate sessions:

Nearest-increment rounding landed on the exact figure here, because the ups and downs cancelled. Always-rounding-up added $21.25 to one client in one week — 0.25 of an hour that nobody worked. That is not fraud, and plenty of contracts allow it, but it should be a term the client agreed to rather than a quirk of how you total your log.

One more rule of thumb: round the total once, not every session. Rounding nine sessions individually applies the error nine times.

What do you do with unbillable time?

Log it anyway, on its own line, tagged as internal. You will not invoice it, but it is the only way to answer the question that decides whether your rate works: how many hours does it take to produce one billable hour? If a 23:15 billable week actually consumed 34 hours of your life, your effective rate is not $85.00 an hour, and no invoice will tell you that — only the log will.

How do you keep a record you can defend?

At the end of each invoice period, export the session list — date, client, start, stop, duration, note — and keep it with the invoice. CSV is the format to send to a bookkeeper or drop into a spreadsheet; PDF is the one to attach for a client who just wants to read it. Exporting a timesheet to CSV or PDF covers the columns a usable export needs, including the trap where a spreadsheet silently reinterprets your times.

Doing all of this on your phone

Hours: Time Card Calculator handles the part of this workflow that people get wrong: the arithmetic. It adds and subtracts hours and minutes directly in H:MM, so 2:45 + 3:15 + 1:20 + 3:30 + 1:55 gives 12:45 rather than a base-10 approximation. One tap flips the total to decimal hours, an hourly rate turns it into pay, the saved history keeps each session you entered, and CSV or PDF export produces the record to file with the invoice. Overnight sessions and negative totals work too, which matters if your Thursday runs past midnight.

Frequently asked questions

How do freelancers track billable hours?

Log a start and stop time for each session with the client name, then add each client's sessions in H:MM at the end of the week, convert to decimal, and multiply by the rate. A notebook plus a time calculator is enough — no background tracker or account needed.

What counts as a billable hour for a freelancer?

Work on the deliverable, client calls, in-scope revisions, and project-specific research. Your own admin, tool setup, pitching, and general skill-building are business overhead, not client time, unless the contract says otherwise.

How do you convert freelance hours to an invoice figure?

Divide the minutes by 60, then multiply by the rate. 12:45 is 12.75 hours, which at $85.00 is $1,083.75. Typing 12.45 instead bills $1,058.25 and loses you 18 minutes of work.

Should freelancers round billable time?

Only to an increment your contract names, and always the same way. Rounding to the nearest 6 or 15 minutes stays close to reality; always rounding up drifts upward — $21.25 on one client in the week above.

Do you need a time tracking app to bill hourly?

No. A timer helps if you switch tasks constantly, but long work blocks only need start times, stop times, and correct H:MM arithmetic. A tracker's failure mode is a timer left running overnight; a written log's is a forgotten line you can fix the same day.

How long should you keep freelance time records?

At least as long as you keep the invoice they support, since the log is the evidence behind the amount. Retention rules differ by country and contract, so check yours — and export each period so the record stays readable.