Most prices that go wrong are not wrong because somebody added up badly. They go wrong because the inputs were thin: half a drawing set, rates from the last job, a quantity estimated by eye. Good arithmetic on bad inputs still gives you a bad number.
These are the steps to price a construction job that we would expect any estimator to follow, whether they work for you, for a contractor, or for an outside service. None of them are clever. All of them get skipped when time is short.
Why prices go wrong before anyone adds up
Think about where a price actually comes from. Somebody reads the drawings, decides what is in the job, measures it, picks a rate for each item and adds it all up. The adding up is the only part a spreadsheet does for you. Every other step is a judgement, and every judgement made in a hurry is a place for money to go missing.
That is why a process matters more than a template. A template tells you where to put the numbers. A process makes sure the numbers are worth putting there. The five steps below are that process, in the order they should happen.
The steps to price a construction job, one by one
Step one: start with what you have actually been given
Before anything gets priced, gather every drawing, the specification, any site survey information and whatever compliance documents exist. Then read them. Not skim, read. Half finished information leads to a price built on assumptions, and assumptions are exactly what come back to bite you once the job starts.
Make a list as you go: what is missing, what is marked TBC, where the drawings and specification disagree. Each item on that list becomes either a query to the client or a written assumption in your price. It should never become a silent guess inside a rate.
Step two: check rates against where they actually stand now
A price is only as good as the rates behind it. Labour and material costs move differently depending on where the job is, and a price built on London rates does not hold up on a rural job three counties away (the reverse is just as true). Rates need checking against current supplier quotes and local labour costs, not carried over from whatever the last job used.
For the bigger packages, get real quotes. For the rest, check your rate library against what you have actually paid on recent jobs. If a rate has not been touched in months, treat it as suspect until proven otherwise.
Step three: measure the quantities properly
Every item gets measured, to NRM2, not estimated by eye or lifted from a similar job without checking it actually matches. Measuring to a recognised standard matters for two reasons. It forces you to deal with every item the rules cover, so things do not get forgotten. And it means anybody else, your QS, a subcontractor, the client's team, can follow what you measured and how.
A proper bill of quantities, itemised and complete, is what lets you price accurately and what a subcontractor can price against without guessing what you meant. It is also the document you will reach for when the first variation arrives.
The rate is where people argue. The quantity is where the money is usually lost. Measure first, and measure properly.
Step four: get someone else to check it
Whoever built the price is the wrong person to check it. They know what they meant, so they read what they meant, not what is on the page. A second person going through the take-off, the rates and the final figure catches the assumptions and gaps the first person cannot see.
A useful check does not have to take long. It should cover:
- Completeness. Walk the drawings and specification and tick off each element against the take-off. Anything shown but not priced is the most expensive kind of error.
- Big quantities. Re-measure the handful of items that carry the most money. A slip on a large item matters more than ten on small ones.
- Rate sense. Scan the rates for anything that looks out of line with recent jobs, then find out why.
- Double counting. Look for items priced in both a subcontract package and your own measured work.
- Arithmetic and totals. Check the spreadsheet formulas, especially on sheets that have been copied from an old job.
Step five: set the final price out clearly
Once the figure is checked, it needs setting out so anyone reading it can see the total, the breakdown behind it and where the contingency sits. Show preliminaries, overheads and margin separately from the measured work. List inclusions, exclusions and assumptions in plain words.
A price nobody can follow gets questioned. One set out clearly, line by line, tends not to be, and when it is, you have the answer on the page. There is a fuller walk-through of this in how a price gets built up for a job.
Why the order of the steps matters
You could do all five in a different order, but you would regret it. Pricing before the information is gathered means pricing twice. Measuring before you have read the specification means measuring the wrong thing. Checking before the layout is clear means the checker cannot follow it. Each step makes the next one quicker and more reliable.
The one-line test
When you think the price is finished, ask whether a stranger could pick it up and trace any line back to a drawing and a rate. If they could, you have followed the steps to price a construction job properly. If they could not, one of the five was skipped, and it is worth finding which before the price goes out.