Difference between a Quote and Estimate.

For many businesses is impossible to offer a standard price for a similar job, as similar job vary according to specific customer needs.
When proposing a cost of a specific job contractors need to take into account time, skills, materials and unforeseen events or circumstances that are beyond the reasonable control that may occur during the execution of the project.
When it's not possible to work from a standard price list, you have to give a quotation or an estimate instead.
An Estimate is not a legal binding contract, that because as the name suggest is simply an estimation or an educated guess by the contractor of how much could cost to complete the job. An estimate is a price within a percentage range of the final cost. When giving Cost Estimate of a project contractors should provide with different prices to take in account various circumstances, this to avoid price surprise once the job is completed if unforeseen events has occurred during the execution of the job.
When a contractor provide an estimate the client may experience price increase, this can result as consequence of unforeseen circumstances or because the contractor need to put in more time or effort to do the work.
The alternative to Estimate is for a client to ask for a definitive quote. As the name suggest a client will know outright the final cost of the project feeling comfortable that the job is completed within client budget.
A quotation represents a fix price offer to complete the job that once accepted by the client cannot be changed even if the contractor has to carry out much more work than expected.
When providing quotation is good practice to specify precisely what the quote cover by making a description list of what the job will involve and the cost associated to each one of them. Also is a good practice to make a disclaimer citing that any jobs occurred outside the job description list may be subjected to additional charges.