Can I charge more than my estimate?

Usually yes, if the extra work was genuinely unforeseen and you told the customer before doing it. What causes disputes is a surprise at the end, not the increase itself.

How much can an estimate change?

There is no fixed rule. Many trades work to a rough guide of ten to fifteen per cent, but the only real protection for both sides is writing down what the estimate assumed.

Should I charge for producing an estimate?

Some trades do where the work needed to produce it is substantial, such as a site survey. If you intend to, say so before you start rather than putting it on the final bill.

Is an estimate binding?

Generally not in the way a quotation is, because it is presented as an approximation rather than an offer of a fixed price. That protection depends on the document actually reading like an estimate, which is why labelling it clearly matters.

How do I stop an estimate being treated as a quote?

Use the word estimate on the document, state that the figure is approximate, and write down the assumptions it rests on. A bare number with a total at the bottom reads like a price whatever you called the file.

Free Estimate Generator

An approximate price, clearly labelled as one. Fill the form, watch it build itself, download the PDF. No sign up, no watermark, and nothing you type is sent anywhere.

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An estimate should read like a forecast

An estimate is your considered guess at what something will cost before the job is fully understood. It is not a lesser quotation, it is a different document with a different promise attached.

Say so on the page. A customer who believes they were given a fixed price will treat any increase as a broken agreement, however reasonable the reason.

If you already know enough to commit to a figure, do that instead and call it a quotation. Estimating when you could have quoted reads as evasive.

The assumptions are the document

What you have been told, and by whom.

What you have not been able to see yet: behind the wall, under the floor, inside the system.

Quantities you have assumed rather than measured.

Anything the customer has to do first, and what happens to the timeline if it slips.

An estimate without its assumptions written down is a number with nothing holding it up.

Telling someone the price has moved

Tell them before you do the work, not when you invoice. Almost every dispute about an estimate is about the surprise rather than the money.

Put the revision in writing with the reason next to it, and reissue the estimate rather than amending it verbally.

Some trades work to an informal tolerance of ten or fifteen per cent before a revision is expected. That is a custom rather than a rule, and it is no substitute for telling the customer.

Estimate, quotation, or a price cap

Use an estimate when the unknowns are real and you would rather not price them as risk.

Use a quotation when you understand the job and the customer wants certainty.

A third option is an estimate with a ceiling: your best guess, plus a figure you undertake not to exceed without written agreement. It gives the customer the certainty they want without you pricing in guesswork.

A worked estimate

The same job, quoted before anyone has seen the existing site's content.

Estimate E-118, issued 2 March.
Design and build, approximately 10 to 14 days at 480.00: 4,800.00 to 6,720.00.
Assumes the client supplies final copy and images by 10 March.
Assumes the existing product data exports cleanly; if it has to be rekeyed, that is extra.

It is labelled an estimate and gives a range, so it does not read like a fixed price someone can hold you to.

The two assumptions are the document. Without them the number is a guess with nothing holding it up.

If the data will not export, the customer hears that before the work happens, not on the final bill.

How to make an estimate

Enter your details and the customer's.
List the work with your best estimate for each part.
Say what could change the price.
Download the PDF.

Questions about estimates

Can I charge more than my estimate?: Usually yes, if the extra work was genuinely unforeseen and you told the customer before doing it. What causes disputes is a surprise at the end, not the increase itself.
How much can an estimate change?: There is no fixed rule. Many trades work to a rough guide of ten to fifteen per cent, but the only real protection for both sides is writing down what the estimate assumed.
Should I charge for producing an estimate?: Some trades do where the work needed to produce it is substantial, such as a site survey. If you intend to, say so before you start rather than putting it on the final bill.
Is an estimate binding?: Generally not in the way a quotation is, because it is presented as an approximation rather than an offer of a fixed price. That protection depends on the document actually reading like an estimate, which is why labelling it clearly matters.
How do I stop an estimate being treated as a quote?: Use the word estimate on the document, state that the figure is approximate, and write down the assumptions it rests on. A bare number with a total at the bottom reads like a price whatever you called the file.