How to Estimate a Job Accurately Before You Quote

To estimate a job accurately, break it into tasks, estimate time and materials for each from past jobs, add a 10 to 15% contingency, and only then turn the total into a quote. That is how to estimate a job without guessing at a single number, which is where both underquoting and overquoting come from. The estimate is your private working; the quote is what the client sees, and it is only as good as the numbers underneath it.

Break the job into tasks

Never estimate a job as one lump sum. Even if the client only sees a few lines on the quote, your own working should list every task, with its materials and hours next to it. Missing tasks are the biggest single cause of underquoting, and a list is the easiest way to spot them.

• Materials: what you need to buy or license for each task, with quantities.
• Labour: hours per task, for you and anyone helping you.
• Overhead: the share of your running costs this job needs to cover.
• Profit: the margin you add once costs are known.
• Contingency: a buffer for the complications that turn up on almost every job.

Use your past jobs as the baseline

If you have done similar work before, start from what it actually cost and how long it actually took, not what you remember. Track your hours on every job, even roughly, so you build a record of real times. After a dozen jobs you will know that a bathroom retile takes you three days, not the two you always hope for.

Check old material prices before you reuse them. Costs, rates and suppliers change, and an estimate copied from last year's job without updating is an estimate at last year's prices.

Allow for complexity, travel and admin time

Two jobs with the same task list are not the same job. A website for a client with a clear brief is different from one for a client who "isn't sure what they want yet". A renovation in an empty house is different from one where the family is still living there. Adjust your hours for:

• Decision-making: more people approving the work means more calls and more waiting.
• Access and travel: parking, stairs, distance to site and trips to the supplier.
• Admin: calls, emails, file management and paperwork. Allow 10 to 20% on top of the hands-on hours.

Add a contingency, and say so

Add 10 to 15% to your estimate for the things you can't see yet: a wall that isn't straight, a supplier delay, a client who changes a small detail. Use the higher end for older buildings, new types of work or clients you haven't worked with before.

Don't hide the contingency. Either show it as its own line ("Contingency, 10%") or mention it in the quote notes. A client who knows it is there is less likely to argue when you use it, and more likely to trust the rest of the numbers.

Estimating mistakes that cause underquoting

1. The "it should only take an hour" trap: estimating the best case instead of the usual case.
2. Ignoring admin time: calls, emails, revisions and bookkeeping are real hours on every job.
3. Not accounting for revisions: "Logo design: 1,000" with no limit on revision rounds can turn into 15 rounds for the same price. State the number included and the price of extra ones.
4. Copying old quotes without updating: old material prices and old rates make a new job look cheaper than it is.
5. Assuming the client understands trade terms: if they don't understand a line, they can't see what it covers, and scope arguments follow.

From estimate to quote

Once the estimate adds up, add your profit on top of the full cost (materials, labour, overhead and contingency), not on materials alone. Our guide on how to price a job walks through that step with a worked example.

Then group your tasks into the lines the client will see. Your working might have 20 tasks; the quote might have six lines, one per stage or deliverable. Put anything the client often questions (call-out fees, waste removal, certificates, travel) on its own line so it doesn't look like a surprise later.

Our free quotation generator takes those lines, adds tax and totals them, so the numbers you worked out match the numbers the client sees. Keep your estimate working next to the quote, too: when the job is done, compare the real hours against it. That comparison is how to estimate a job better next time.