An estimate is your professional judgement of what a job is likely to cost before all the facts are known. It is the right document when there are genuine unknowns: hidden damage behind a wall, work billed by the hour, or materials whose prices could move before you buy them. A good estimate gives the customer a realistic figure to plan around while being honest that the final bill may differ, and it sets out what would cause that difference. The generator on this page opens as an estimate, so you can itemise labour and materials, add a contingency, and download a PDF the customer can approve.
When an estimate is the right document
Customers often ask for a quote when what they really need is an estimate, and giving a fixed price when you cannot see the whole job is how tradespeople lose money. Reach for an estimate whenever the final scope depends on something you will only discover once work begins, or when the work is naturally open-ended and billed by time. Make sure the document is labelled as an estimate so nobody mistakes it for a firm offer.
- Repairs where the extent of the fault is unknown until you open things up
- Hourly or day-rate work where the time required is uncertain
- Projects that depend on materials whose prices fluctuate
- Early-stage conversations where the customer needs a ballpark to decide whether to proceed
- Jobs with several possible approaches, each with a different cost
What a good estimate contains
An estimate should be just as carefully laid out as a quotation; the difference is in how the figures are framed, not how much care goes into them. Alongside the usual identifying details, the document needs to explain the basis of the numbers, so the customer understands why the price might change and by roughly how much.
- The word Estimate, a reference number, and the date, so it can be matched to the later invoice
- Your details and the customer's details, plus the address where the work will happen
- A description of the work and the assumptions you have made about it
- Itemised labour as hours or days at your rate, and materials with quantities and unit prices
- A contingency line or a low-to-high range, with a note of what would push the price towards the top
- If you are registered for VAT/GST, a note that tax will be added at the applicable rate
- An expiry date and a statement that the final invoice will reflect the work actually carried out
A worked example
Imagine a plumber asked to replace a kitchen mixer tap and trace a slow leak under the sink. The estimate lists labour at 3 hours times 55.00, giving 165.00; a replacement mixer tap at 95.00; and fittings and consumables at 18.00. The expected subtotal is 278.00. Because the leak might turn out to be in the pipework behind the cabinet, the plumber adds a contingency line: replacement of up to two metres of pipework if required, up to 120.00. The estimate therefore shows an expected cost of 278.00 and a likely maximum of 398.00.
The customer now knows the probable cost, the worst reasonable case, and exactly what would trigger it. If the pipework is fine, the invoice comes in at 278.00. If it is not, the plumber can point to the contingency line that was agreed in advance. In the generator above, you can enter the contingency as its own item and describe the condition in the notes.
Hourly estimates and not-to-exceed limits
When you bill by time, the estimate is really a forecast of hours. Base it on similar jobs you have done, break the work into stages and estimate each one, and then add a buffer of roughly ten to twenty percent for the things that always take longer than expected. Present the result as a range of hours multiplied by your rate, so the customer can see how the money follows the time.
Many customers will happily agree to an hourly estimate if you offer a not-to-exceed limit: a cap you will not pass without their written approval. It costs you nothing if the job runs as expected, and it gives the customer the confidence to say yes. If you find yourself approaching the cap, stop and explain before continuing; a quick message at that moment is far better received than a surprise on the invoice.
From estimate to final invoice
Because the estimate is not the final price, the invoice that follows needs to explain itself. Keep the estimate number on the invoice, use the same line descriptions, and show the actual hours and materials against each. Where the figures differ from the estimate, add a short note saying why, such as the pipework contingency being used or fewer hours being needed. Customers accept variations they understand and dispute variations they do not.
- Get the customer's agreement before doing any work that will push the bill above the estimate
- Reference the estimate number and reuse its line descriptions on the invoice
- Show actual quantities and hours next to each line, not just totals
- Explain each difference from the estimate in a sentence
- If the job came in under the estimate, say so; it builds trust for next time
Common estimating mistakes
Most estimating errors are errors of omission rather than arithmetic. Travel time, waste disposal, parking, and the hour spent collecting materials are real costs that are easy to leave out when you are keen to win the job. Pricing materials from memory rather than checking current prices is another frequent slip, as is rounding the total down to look competitive and then absorbing the difference. Finally, an estimate without an expiry date or a list of assumptions gives you nothing to point to when circumstances change. The checklist of elements above exists precisely to catch these before the document goes out.
Helpful guides: Estimate vs Quote: What's the Difference (and When to Use Each)? / How to Invoice as an Individual (No Company Needed) 2026 / Free billing calculators
Frequently Asked Questions
Is an estimate legally binding?
Generally no: an estimate is understood to be an approximate figure that may change once the work is under way, which is why it must be clearly labelled as an estimate rather than a quotation. That said, a final bill that far exceeds the estimate without warning or explanation can still be disputed, so communicate before costs rise and keep the customer's agreement in writing.
How much can the final invoice differ from the estimate?
There is no universal rule, but many professionals aim to stay within ten to fifteen percent of the estimated figure and treat anything beyond that as something to discuss with the customer before continuing. Stating a range or a contingency on the estimate itself sets expectations and makes a higher final bill far easier to accept.
Should I charge for providing an estimate?
A simple visual estimate is usually offered free as part of winning the work. A detailed estimate that requires a survey, measurements, or diagnostic time can reasonably be charged for, provided you say so before the visit. Many businesses credit the estimate fee against the job if the customer goes ahead.
Should I send an estimate or a quotation?
Send a quotation when you can see the whole job and are comfortable committing to a fixed price. Send an estimate when there are unknowns that could change the scope, when the work is billed by time, or when the customer only needs a figure to decide whether to proceed. Labelling the document correctly protects both of you.
How do I show a price range on an estimate?
Either list the expected items and add a separate contingency line that explains what it covers, or show a low and a high figure with a sentence describing what would move the price from one to the other. Both approaches work in the generator above; the key is that the customer can see what drives the difference.
Do I include tax on an estimate?
If you are registered for VAT/GST, say so and either show the tax at the applicable rate or state clearly that it will be added to the final invoice. If you are not registered, note that no tax applies. Leaving tax unmentioned is one of the most common reasons an invoice comes as an unwelcome surprise.