The unbilled hours calculator

Nothing is sent anywhere. The sum happens in your browser and we never see the numbers.

What this number is, and what it is not

It is not money somebody owes you. It is the size of the gap between the hours you work and the hours you can evidence, priced at your own rate.

That distinction matters, because the gap is not all recoverable. Some of those hours were genuinely unbillable: the admin, the proposal that went nowhere, the twenty minutes finding a file. Some were billable and simply never made it onto an invoice. The number above is the outer limit of what better recording could be worth, not a promise.

It is still worth calculating, because most people have never put a figure on it at all, and an unmeasured problem never gets fixed.

Why the gap exists at all

Three reasons, and none of them is laziness.

You reconstruct rather than record. Almost nobody writes time down as it happens. They write it down on Friday, from memory, and memory smooths a fragmented day into three tidy blocks. The short pieces vanish first, and the short pieces are most of the day.

You underestimate, consistently. The planning fallacy has been measured since Kahneman and Tversky named it in 1979: we underestimate how long our own work takes even when we know it has overrun before. Reconstructed timesheets are not neutral. They are biased low.

The timer only works when you remember it. A manual timer is accurate about the hours it captured and silent about the ones it missed, which makes it look complete when it is not.

How to find your real number instead of guessing it

The figure you typed above is a guess. Here is how to replace it with a measurement, and it takes a week.

1. For five working days, record what you are doing at a fixed interval. Fifteen minutes is ideal, half an hour is enough.
2. Do not tidy it. Leave the gaps as gaps — the gaps are the answer.
3. On Friday, add up the hours you can name and subtract that from the hours you were actually at work.
4. Put that difference into the box above.

Most people find the real figure is larger than the one they guessed. If yours is smaller, that is genuinely good news and you can stop reading.

What to do about it

In order of how much they usually help:

• Record closer to the event. Every hour between doing the work and writing it down costs you detail, and detail is what you bill from.
• Keep the unbillable hours too. Knowing that admin takes nine hours a week is how you decide to hand it to somebody, and you cannot decide that from a feeling.
• Mark what was reconstructed. If half your week was filled in afterwards, the total is an estimate and should be treated as one — particularly if a client ever queries it.
• Raise your rate before you chase the gap. Often the faster arithmetic.

Questions people ask

Is this the same as my utilisation rate?

No. Utilisation is billable hours as a share of available hours, and it assumes you know both numbers. This is about the hours you cannot place at all, which sit outside that sum entirely and usually get quietly absorbed into whichever project is nearest.

Four hours a week sounds like a lot. Is it?

It is about forty-eight minutes a day, and it is a common answer once people measure rather than estimate. If you have never measured, four is a reasonable place to start; a week of recording will tell you whether it is two or nine.

Does recording my time actually recover any of it?

Some of it, not all, and the honest mechanism is not what people expect. It is rarely that you bill more hours. It is that you see where the unbillable ones go, and change something. Anyone promising you the whole figure back is selling you something.

What rate should I use if I bill by the day or by the project?

Divide your day rate by the hours actually in your working day, not by eight — most people's is longer. For project work, divide a recent fee by the hours that project really took, which is a sobering exercise in itself.