You told the client the bathroom retile would take three days. It took five. You did not get paid for the extra two, and the next job started late because this one ran over. If that sounds familiar, the problem is not laziness or bad luck. It is a broken way of estimating job time. Getting it right is a learnable skill, and your own work history is the single best tool you have.
This is about estimating how long the work will actually take, the hours and days on the tools. It is not about writing a price quote. When your time estimate is honest, your pricing, your schedule, and your stress levels all fall into line.
Why tradespeople chronically underestimate
Almost everyone who works with their hands underestimates how long a job takes. It is not a character flaw, it is how the human brain works on a busy day. A few forces are working against you:
- Optimism bias. You picture the job going perfectly: the right parts on the van, no surprises behind the wall, the client out of your way. Real jobs rarely run like the version in your head.
- You only count the visible work. The cuts, the fixing, the fitting. You forget the invisible time that surrounds it.
- You remember your best day, not your average day. That one time you hung six doors before lunch becomes your mental benchmark, even though it was an outlier.
- Round numbers feel safe. "Call it a day" or "about a week" gets quoted, then reality lands somewhere past it.
The fix is not to be pessimistic. It is to be specific, and to base your numbers on what actually happened last time, not what you hope happens this time.
The hidden time that eats your day
The biggest gap between your estimate and reality is almost always the work that surrounds the work. Before you estimate anything, build the habit of accounting for these:
- Setup and breakdown. Unloading the van, laying dust sheets, running leads, setting up the saw station, then packing it all away. Easily 30 to 60 minutes at each end of every day.
- Travel. Not just the commute. Trips to the merchant for the part you did not know you needed, moving between two job sites, parking and walking gear up three floors.
- Cleanup. A clean handover takes real time, and clients judge you on it. A builder's clean on a kitchen can be half a day on its own.
- Snags and surprises. Rotten joists under the old floor, a soil pipe in the wrong place, a wall that is not square. You cannot predict the specific snag, but you can predict that there will be one.
- Client interruptions. "Quick question" five times a day adds up. So do decisions the client has not made yet about tile, paint, or layout.
- Waiting and drying. Plaster, screed, adhesive, paint, and sealant all need time you cannot rush. It may not be labour, but it controls when you can do the next step.
A useful rule of thumb: if your gut says "two days of work," the visible work is two days, and the hidden work pushes the real total closer to three.
Break the job into tasks and estimate each one
One big number for a whole job is almost always wrong, because your brain cannot hold the full job in one thought. The reliable method is to break the job into tasks and estimate each task on its own. A task you have done a hundred times is far easier to judge than a job you have never seen before.
Take a small bathroom retile. Instead of "three days," list the tasks:
- Strip old tiles and clear waste: half a day
- Prep and level walls and floor: half a day
- Tile the floor: half a day
- Tile the walls: one day
- Grout, seal, and silicone: half a day
- Setup, cleanup, and trips to the merchant across the job: half a day
That adds up to three and a half days, not three. Already you have caught half a day you would have eaten yourself. Estimating task by task forces the hidden work into the open, and it makes the next step possible: comparing each task to what it really took last time.
Your tracked-time history is the best predictor you have
Here is the part that changes everything. The single most accurate way to estimate a job is to look at how long the same kind of work took you before. Not a trade-magazine average, not a mate's guess, your own real hours, on your own jobs, at your own pace.
This is exactly why tracking your time matters beyond just billing. Every time you run a timer on a job, you are quietly building a private database of how long your work actually takes. After a handful of bathrooms, you stop guessing that tiling a wall takes "about a day" and you know it takes you 7.5 hours, every time, give or take.
With Billr, that history is already there for you. A project rolls up all the tracked time logged against it, so when you finish a job you can see exactly what each phase cost in hours. Pull up your last three jobs of the same type and you have a grounded number to start from, instead of an optimistic guess. If you are not yet capturing your hours cleanly, start with one-tap time tracking. It is the raw material every accurate estimate is built on. (If your time data is messy, it is worth avoiding the common time-tracking mistakes that quietly ruin your numbers.)
Add a realistic buffer, not a panic margin
Even with good data, no job goes exactly to plan. So you add a buffer: a deliberate slice of contingency time for the snags you know are coming but cannot name yet. This is not padding to cover laziness. It is honest planning for the real world.
How much buffer depends on how well you know the work:
- Familiar work, known property: 10 to 15 percent. You have done this exact thing many times.
- Familiar work, new property: 15 to 25 percent. You know the task, but old buildings hide surprises.
- Unfamiliar work or heavy unknowns: 25 to 50 percent. First time with a material, a listed building, or a job you have never priced.
On that three-and-a-half-day bathroom in a 1930s house, a 20 percent buffer adds most of a day, taking your honest estimate to about four and a half days. That extra day is what turns a five-day overrun into a job that finishes when you said it would. The client remembers that you finished on time far more than they remember the extra day in the quote.
Track estimate versus actual, and get better every job
This is the loop that makes you genuinely good at estimating, and almost nobody does it. After every job, compare what you estimated against what it actually took. The gap is your tuition. It tells you exactly where your instincts lie to you.
Billr is built for this comparison without any extra paperwork. When you set up a project you can give it a time estimate and a budget estimate. Then, as you and your team track hours against it, a time-tracked progress bar shows you the percentage complete in real time, and budget tracking shows earnings against your budget estimate. You are not waiting until the end to find out you blew the estimate. You can see at day three that you are 80 percent through the hours with two days of work left, and adjust before it hurts.
You can do the same at the task level: each task can carry its own time estimate, and the tracked time accumulates against it automatically. Over a few months this turns into a feedback machine:
- You estimate a job from your last similar one.
- You track the real hours as you work.
- You compare estimated against actual when it is done.
- You feed that learning into the next estimate.
Maybe you discover you always underestimate plastering by 30 percent, or that small jobs cost more in setup and travel than the labour itself. Once you can see the pattern, you can price for it. This is also the foundation for setting an hourly rate that actually covers your time, because a rate is only fair if it is built on honest hours.
A worked example: the EUR 924 garden wall
Say you quote a small rendered garden wall. Your gut says "two days, call it EUR 800." Instead, you check Billr and find your last two similar walls took 17 and 19 hours of tracked time. You break this one into tasks: footings and setting out (4 hours), block laying (8 hours), rendering (5 hours), plus setup, cleanup, and a merchant run (3 hours). That is 20 hours. The property is new to you, so you add a 20 percent buffer, bringing it to 24 hours. At a EUR 38.50 hourly rate that is EUR 924 of labour, not EUR 800. You have just protected over EUR 120 of your own time that your gut was about to give away, and you will almost certainly finish when you promised.
Key takeaways
- Underestimating is the default. Beat it with specifics, not optimism.
- Always account for the hidden time: setup, travel, cleanup, snags, and waiting.
- Break every job into tasks and estimate each one separately.
- Your own tracked-time history from similar past jobs is your most accurate predictor.
- Add a buffer scaled to how well you know the work, typically 10 to 50 percent.
- Compare your estimate to the actual hours after every job, and feed the lesson forward.
FAQ
How do I estimate a job I have never done before?
Break it into smaller tasks you have done before and estimate those, then add a larger buffer (25 to 50 percent) for the unknown parts. After you finish it once and have tracked the real hours, your next estimate of that job will be far more accurate.
Does Billr create a quote or estimate document?
No. Billr does not produce quote documents. What it does is help you estimate work duration: you can set a time estimate and budget estimate on a project and on individual tasks, then track your real hours against them so you can compare estimated versus actual and improve. The estimating skill is yours; Billr gives you the data to do it well.
How big should my buffer be?
It scales with uncertainty. For familiar work in a property you know, 10 to 15 percent is usually enough. For unfamiliar work, old buildings, or a job type you have never priced, 25 to 50 percent is more realistic.
What is the fastest way to start collecting my own time data?
Run a one-tap timer on every job from now on, tagged to the client, project, and task. Even a few weeks of honest hours gives you a baseline that beats guessing, and it builds with every job you complete.
Want estimates that get sharper with every job instead of burning you again and again? Start tracking your real hours with Billr, set a time estimate on your next project, and watch the gap between estimate and actual close. See how projects track time and budget, and turn your own history into estimates you can stand behind.