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Unbilled Hours Calculator

The calls that never get logged, the hours written off at invoice time, the round-downs — priced with your own numbers, with the working shown. This is money you already earned.

3Leaks, one number
46Working weeks/yr
FreeAnswer, no signup
Hours actually logged against client work in a typical week — not contracted hours.
The leak — assumptions you set, not statistics
5%
The calls, the “quick looks”, the email threads answered between meetings — done for the client, invisible to the timesheet.
5%
Hours that reach the draft invoice and get crossed out because the total “looks too high”.
2%
The 50-minute task logged as 45. The 20-minute call logged as 15. Small, chronic, compounding.
Total leakage12%
Revenue leaking · your numbers
£61,934 / year
Per month£5,830
Leaked hrs / week15.84
Client-days / year91

The working — every step, your numbers

A deliberate simplification: leaked hrs/wk = people × logged hrs × total leak %. Strictly, unlogged work happens on top of the hours you see logged — so if anything this understates it. A year is counted as 46 working weeks (holidays, bank holidays and sickness taken out); a client-day is 8 hours.

Now find out where it’s leaking

The calculator sizes the leak. The free Unbilled Hours Tracker (Excel) shows you where it is — worked vs logged vs invoiced hours, per person, per week:

  • The three numbers that never usually meet: hours worked, hours logged, hours invoiced
  • Leakage % per person, RAG-lit — green under 8%, red above 15%
  • £ lost per week and per year at your own charge-out rate
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📗 The fix starts with logging at the time — grab the free Excel Timesheet Template (hours, breaks and billable value, per person).

This is money you already earned

No scare statistics. The sliders are your assumptions, the arithmetic is shown, and the number at the end is yours — built from work your team has already done.

Never logged

The in-between work — calls, quick looks, favours — done for the client but invisible to the invoice because it never reached a timesheet.

Written off

Logged, delivered, then quietly crossed off the draft invoice at month-end because nobody wants to defend the total.

Rounded down

Fifty minutes logged as forty-five, every task, every day. No single entry matters; the habit compounds into real money.

The working, shown

Every step of the calculation, in the open — so you can put the number in front of the team and nobody argues with the arithmetic.

Unbilled hours — questions

Where do unbilled hours actually go?

Four places, mostly. Work that never gets logged — the calls, the “quick looks”, the email threads answered between meetings. Scope creep absorbed quietly, because nobody wants the awkward conversation. Write-offs at invoice time, when the total “looks too high” and hours get crossed out. And round-down habits — the 50-minute task logged as 45. None of them feel like money on the day; all of them are.

How do I reduce write-offs?

Track time at the time, not at month-end — a timesheet reconstructed from memory on the 31st is guesswork, and guesswork is what gets written off. Show clients the log as you go, so the invoice is never a surprise. And when scope changes, say so when it changes — an agreed extra is billable; a silently absorbed one never is.

How much unbilled time is normal?

There’s no universal number — which is why the sliders here are assumptions you set, not statistics we quote. Run your own last month instead: hours actually worked on client work versus hours invoiced. Most teams that measure it find the gap bigger than they guessed, but the point is to measure yours, not to trust an average.

How accurate is this calculator?

It’s deliberately simple, and it says so: leaked hours = people × logged hours × your total leakage percentage, and a year is counted as 46 working weeks. Strictly, unlogged work happens on top of the logged hours, so if anything the model understates the leak. It’s your own arithmetic on your own assumptions — move the sliders and the answer is yours.

Why is this calculator free?

We make Landing — the all-in-one platform where time is tracked where the work happens and flows straight to the invoice. A genuinely useful free calculator is the best introduction we know; the answer is yours either way. No payment, no trial, no strings.

When the spreadsheet stops scaling

Meet Landing — time tracked where the work happens

A calculator sizes the leak; plumbing fixes it. In Landing, timesheets live inside the projects, boards and retainers — an hour logged on a card flows straight through to the invoice and the margin report. Nothing falls between the tools, because there’s nothing between the tools. One platform, 40+ connected tools, for agencies, teams and growing businesses.

See Landing in action →
TimesheetsEngagements & retainersInvoicingMargin reporting+ 40 more