Search for time tracking software for consultants and you get pages that look alike: a feature list, a free-trial button, and the claim that every untracked hour is lost revenue.

That's only true if you bill by the hour. On a fixed fee, an unlogged hour costs nothing on the invoice. It costs you the knowledge that the project ran 30 hours over, so you quote the next one the same way. On a day rate, you prove days, not minutes. The billing model decides what the record has to prove, and the record decides the tool. None of the top results I could read starts there, so this post does.

I build Timex, an automatic time tracker for the Mac, so I have a stake in the answer. I'll say where it fits and where another tool is the better buy.

Short answer: pick time tracking software for consultants by billing model, not by feature count. Hourly and day-rate work need a same-day record per client that you could defend line by line: a manual timer with billable rates, or an automatic tracker feeding your invoice. Retainers and fixed fees need hours against a budget, to catch scope creep and price the next deal. Once several people bill, you need a team plan or a PSA suite with approvals and utilization. Whatever you pick, close the week's record in ten minutes every Friday.

How to choose time tracking software for consultants: start with the billing model

Each billing model asks the record a different question, and consultants are spread across all of them. In Consulting Success's fee study of nearly 1,000 consultants, 30% price by project, 29% hourly, 16% on a monthly retainer, 15% on value and 10% by the day.

The page doesn't say how respondents were recruited, and it's published by a consulting-coaching business, so read the split as rough. If you run more than one model, every matching row applies.

How you bill What the record must prove What to capture Tool shape that fits
Hourly Each billed hour was worked, for this client, on this task Client, task, duration and a one-line note, logged the same day Manual timer with billable rates, or an automatic tracker plus an invoicing tool
Day rate Days and half-days worked, by the contract's definition of a day Dates, start and end times, hours per day Any timesheet; an automatic tracker records start and end for you
Retainer (bank of hours) Hours used against the monthly allotment, and what they went to A running total per client per month Timer or tracker with a budget view
Fixed fee Actual hours against the estimate, and which work was out of scope Hours by phase or deliverable, plus a dated log of change requests Any tracker with project budgets; automatic capture catches the unplanned work
Value-based Nothing to the client; to you, the effort behind the price Rough effort per engagement The lightest thing you'll keep running
Any model, two or more people billing Who worked on what, at which rate, and who approved it Per-person hours, rates, approvals A team plan or a PSA / practice-management suite

Most generic advice breaks on the bottom four rows. If you never send hours to a client, invoicing features are dead weight; you need something that keeps recording when you forget it exists.

Hourly and day-rate work: the record is the invoice

When you bill time, the record has to survive the client reading it. That means it was written close to when the work happened, at a stated increment, without unrelated tasks lumped into one line (block billing).

Who actually uses 6-minute billing increments (0.1 hour). The clearest written rule I found is in US bankruptcy courts. The US Trustee's 2013 fee guidelines for attorneys in large Chapter 11 cases say time "should be recorded contemporaneously in increments of no more than one tenth (.1) of an hour", and read a run of half- and whole-hour entries as a sign of lumping.

The older general guidelines in 28 CFR Part 58 ask every professional employed in a case for tenths of an hour, with task categories written for accountants and financial advisors.

Outside settings like those, I found no universal consulting standard, so put a billing increment in your engagement letter.

Rounding each entry adds up. Take twelve 5-minute tasks in a day: emails, a quick review, a call-back. That's 60 minutes of work.

  • At a 0.1-hour minimum per entry: 12 × 0.1 = 1.2 hours billed, 20% more than the work.
  • At a 0.25-hour minimum per entry: 12 × 0.25 = 3.0 hours billed, three times the work.

Unless your contract requires per-entry rounding, add up the client's time for the day and round once. The number is smaller, and you can defend it.

Memory is a weak record. When Robinson and colleagues (2011) compared people's estimates of their working week with their time diaries, the estimates ran 5–10% high, mostly among people who reported long weeks.

BLS economists Frazis and Stewart (2014) found internal inconsistencies in that study's main table and concluded any such bias is small; in their own comparison the gap ranged from 3.7 hours over to 0.9 hours under, depending on how the question was asked.

So the research doesn't settle which way recall errs, or by how much. Either way, a Friday reconstruction is something neither you nor your client can check.

A "day" is a contract term. One European Commission framework contract for IT services defines a person-day as eight hours and invoices time-and-means work from timesheets.

A 2025 EU tender annex bills by days performed, with a half-day as the minimum unit, and counts a full year as 220 working days per person.

So a day-rate consultant still needs hours per day: they separate a billable day from a billable half-day.

Fixed fees and retainers: track hours to protect the margin

On a fixed fee, hours never reach the invoice, but they're the only way to know what you earned. A worked example:

  • Fee $12,000, estimate 80 hours, so a planned rate of $150 an hour.
  • Actual 110 hours, so an effective rate of $12,000 ÷ 110, about $109 an hour.
  • The 30 extra hours cost $4,500 at the planned rate.

Without the record, all you know is that the project felt long, and you'll quote the next one at 80 hours again.

Scope creep needs dated evidence. In PMI's 2018 Pulse of the Profession survey, 52% of projects experienced scope creep. The remedy is contractual, and contracts run on hours.

The AIGA Standard Form of Agreement for Design Services bills client-requested changes outside the scope at the designer's hourly rate, on top of the agreed price. You can only invoice that if the change-request hours were logged separately, with dates, while they happened.

Retainers need the burn mid-month. On a bank-of-hours retainer, the useful number is how much of the allotment is gone by the 15th. A month-end total arrives too late to have the conversation.

Value pricing is where the experts disagree. Ron Baker is known for his campaign to "bury the billable hour and trash the timesheet" (IFAC interview, 2013), aimed at the timesheet as a pricing tool.

Ryan Lazanis ran his accounting firm on fixed monthly subscriptions with no timesheets and wrote up five years of it in 2018. It worked, but he describes a year or more of pricing mistakes that probably cost money, and calls the lack of an easy way to produce a price the biggest drawback. He plans capacity forward instead.

My read: the client shouldn't see hours on a value-priced deal, but you still want a private effort record to price the next one, as long as keeping it costs you nothing.

Utilization rate: what it is and why benchmarks disagree

The utilization rate formula is billable hours divided by available hours. "Available" has no fixed definition, so benchmarks that look comparable aren't.

  • SPI Research's 2025 benchmark divides annual billable hours by 2,000. It calls anything over 75% ideal, about 1,500 billable hours a year, and found the 2024 average at 68.9%: 67.4% for management consultancies, 64.4% for agencies, 64.3% for firms with fewer than 10 people.
  • The Deltek Clarity A&E study divides the cost of labor charged to projects by total labor cost. Its median for architecture and engineering firms was 61.1% in fiscal 2024 and 58.9% in fiscal 2025.

For 2024, SPI put A&E firms at 70.3% while Deltek's median was 61.1%: different samples, different denominators, not comparable.

The denominator alone moves your target. Take that EU tender's 220-day year at 8 hours and you have 1,760 available hours, so a 75% target is 1,320 billable hours, not SPI's 1,500.

For solo consultants I found no credible benchmark. Firm numbers assume someone else sells and chases invoices; you do both. Pick one definition, track it weekly, and compare yourself with your own last quarter. That needs proposals and admin in the record too, and those are the hours nobody starts a timer for.

Notes for accountants, architects, designers and small agencies

Time tracking for accountants. The 2023 National MAP Survey of 1,117 firms, run by the AICPA's PCPS and CPA.com, put firmwide utilization at 59.6%, down from 62.3%; the Journal of Accountancy's write-up suggests staff at firms that stress realization "may be disposed to under-record billable time."

If you bill in a US bankruptcy case, the tenth-hour rule above applies to you. If your firm needs deadlines and client workflow alongside time, buy a practice-management suite, not a time tracker.

Time tracking for architects. B101 agreements allocate the fee by design phase. Vanderbilt University's standard B101-2017, for example, splits the basic fee for progress payments into 20% schematic design, 25% design development, 35% construction documents, 2% procurement, 15% construction and 3% closeout. Log hours by phase and you see early when schematic design has eaten its 20%.

Time tracking for designers. The AIGA agreement above expects proposals to quote a total price, usually a fixed fee, and bills out-of-scope changes by the hour. Keep each change request as its own dated entry so it can become a change order.

Time tracking for agencies. Once more than one person bills, you need per-person time and rates in one place.

Prices checked October 2026: Harvest has a free plan with invoicing for one seat and two projects, and team plans from $9 per seat a month billed annually.

Clockify is free for up to five users, but free reports cover one month and export only to PDF; billable rates start on Basic and invoicing on Standard, at $3.99 and $5.49 per seat a month billed annually.

Toggl Track puts billable rates on its paid Starter plan.

The 10-minute weekly routine

Do this every Friday, whatever tool you use. It turns a pile of entries into something you can invoice from.

  1. Fill the gaps (2 minutes). Add calls, meetings and travel: anything that happened away from the keyboard.
  2. Assign the orphans (3 minutes). Every unlabeled block gets a client and project, or gets marked non-billable.
  3. Check every budget (2 minutes). Retainer burn against the allotment, fixed-fee hours against the estimate. If the budget is going faster than the work, tell the client this week.
  4. Log scope changes (2 minutes). One line per out-of-scope request: the date, what was asked, hours so far. That line is your change-order evidence.
  5. Write down utilization (1 minute). Billable hours ÷ available hours, with the same definition every week.

For the format, the timesheet template has you covered. Once the week is clean, you can invoice hours worked from a CSV export in about ten minutes.

Where Timex fits, and where it doesn't

Timex is an automatic tracker for one person on a Mac running macOS 15 or later on Apple Silicon. It records the frontmost app, window title and active browser tab URL into one SQLite file on your disk, and stops counting after 120 seconds without input unless the front app is playing audio or the mic is live, so calls still count.

After five or more minutes away, it offers to turn the gap into a categorized manual entry. Website and keyword rules sort the day into client categories. Export a daily summary CSV for your invoice, or drop the Timex database itself (the .sqlite file, or the .zip that Settings exports) into the free timesheet PDF tool and set an hourly rate.

Activity data never leaves your Mac, which matters when window titles carry client names. It's $49 once, for up to three Macs.

In the table above, that makes it a capture layer for a solo consultant's hourly, day-rate and fixed-fee work, and a private effort record for value pricing. If you already run a timer, here's how to track billable hours by checking it against the log.

What it doesn't do: team dashboards, invoicing, calendar integration, Windows or iPhone. It can't see phone calls or meeting rooms, and it can't split one browser tab between two clients; those need manual entries. An agency with several people billing should use a team plan from the tools above. An accounting firm that needs practice management should buy that.

The short version

Decide what your billing model needs the record to prove, pick the lightest tool that proves it, and close the week in ten minutes. If you work solo on a Mac and keep forgetting the timer, Download Timex. The trial is 100 hours of tracking with no card and no time limit, about two and a half working weeks of real client work before you pay.

— DK