Builder quote comparison calculator
Three quotes, three different ideas of what the job is. This puts them on one basis: your allowance added back for anything a quote leaves out, provisional sums swapped for what you actually expect to spend, the same tax footing on all three, and the weeks on site costed if the work puts you out of the house. Then it ranks them on true cost. Free, no sign-up, eleven currencies, and no country’s tax rate assumed anywhere.
Everything is worked out in your browser. Nothing you type is uploaded, saved or shared. Last updated 8 August 2026.
The tax rate is only used on a quote you mark as excluding tax. Put in your own local rate: sales tax and VAT differ by country, by type of work and sometimes by the builder’s registration, so nothing is filled in for you. The weekly cost is rent, storage, eating out or anything else the work costs you while it runs. Leave it at zero if the job does not displace you.
1. Everything the job needs
One list, used against all three quotes. Put your own allowance against anything you would have to buy separately if a builder left it out. Anything left at zero is ignored, so you only need figures for the lines that matter to you. Rename a row, add your own, or delete what does not apply.
2. Quote A
3. Quote B
4. Quote C
Leave the price at zero if you only have two quotes.
How to compare builder quotes like for like
Four adjustments. Everything else is reading the quote carefully.
Quoted price
+ Tax, if the quote is priced without it
- Every provisional sum inside the quote
+ What you actually expect those items to cost
+ Your allowance for anything the quote leaves out
+ Weeks on site x your cost per week
= TRUE COST1. Put the prices on the same tax basis
A quote priced without tax next to a quote priced with it is not a 20% difference, it is a formatting difference. Read each quote for the words rather than assuming, because whether tax applies at all, at what rate, and on what part of the work varies by country and by the type of job. Some renovation and energy work is charged at a reduced rate in some places, and a builder below a registration threshold may not charge it. That is why this page asks you for the rate instead of filling one in.
2. Replace every provisional sum
A provisional sum is a placeholder in the total for something nobody can price yet. It looks like a price, it is not one, and different builders put different placeholders against the same item. Take the placeholder out and put in the figure you expect to actually spend, then both quotes are carrying the same assumption. The commonest place this bites is a kitchen: one builder allows 3,000, one allows 8,000, and the kitchen you want costs 5,500 whoever fits it.
3. Add back what is missing
This is where most of the movement is. Write one list of everything the job needs, price the lines that matter, then read each quote against your list. If a quote excludes scaffolding, add your scaffolding allowance to that quote. You are not penalising the builder, you are recognising that you will be paying for it either way.
4. Cost the time, if the time costs you
Twelve weeks instead of eight is a month of rent, storage or eating out. If none of that applies to you, leave the weekly figure at zero and the calculation ignores it. If it does apply, put a real number in and let it fall on whichever quote is slower.
What this does not do
It does not price the work, and it does not tell you whether a number is fair for your area. It also cannot see the things that decide most renovations: whether the builder turns up, whether they finish, and whether the two of you will be able to talk to each other in week nine. References and a look at a finished job are worth more than any arithmetic on this page.
A worked example
The default figures, and the reason the cheapest quote is not the cheapest quote.
Three quotes for the same single-storey rear extension. Headline prices of €42,000, €38,500 and €49,000, so the order looks obvious. Then you read them.
Marchetti’s €38,500 is priced without tax, and the quote stops at plastered walls: no making good after first fix and no decoration, which is €3,600 on your own list. Hollis includes almost everything but carries a €3,000 provisional sum for kitchen units against a kitchen you have already chosen at €5,500, and excludes decoration. Nordvik is dearer on paper and includes the lot.
The page opens with the tax rate at zero, because the right rate depends on where you are and what the work is, and it warns you that Marchetti is priced without tax while nothing is being added. Put 20 in the tax rate box and the table below is what you get.
| Hollis & Son | Marchetti | Nordvik | |
|---|---|---|---|
| Quoted price | €42,000 | €38,500 | €49,000 |
| Tax added | €0 | €7,700 | €0 |
| Provisional sum removed | −€3,000 | €0 | €0 |
| Real cost of those items | €5,500 | €0 | €0 |
| Missing scope added back | €2,400 | €3,600 | €0 |
| True cost | €46,900 | €49,800 | €49,000 |
| Weeks on site | 8 | 10 | 7 |
The lowest headline is €10,500 below the highest. The true costs are within €2,900 of each other, and the quote that looked cheapest by a distance finishes last. Nordvik, which most people would have discarded at first glance, comes in €800 below Marchetti and is the only one of the three where nothing is left to find out.
Now add a weekly cost. If you are renting somewhere while the work runs at €450 a week, Hollis adds €3,600 for eight weeks, Marchetti €4,500 for ten and Nordvik €3,150 for seven. True costs become €50,500, €54,300 and €52,150, and the gap between first and second widens to €1,650. Speed is worth money when you are paying to be somewhere else.
What builders leave out, and roughly what it costs you
The exclusions list is the most useful page of any quote, and it is usually the one nobody reads.
These are the lines that most often sit outside a price. No figures are given for them, deliberately: labour rates, hire charges and waste disposal costs are local, and a number from another country is worse than no number. Get one price for the lines that apply to you and reuse it across all three quotes, which is what the allowance column on this page is for.
| Item | The question to ask |
|---|---|
| Scaffolding and access | Who hires it, for how many weeks, and who pays if the job overruns the hire period. |
| Skips and waste | How many, and whether removing the old kitchen, bathroom or roof covering is inside the price. |
| Site protection | Floor protection, dust screens and whether furniture is moved or you move it. |
| Structural engineer | Who commissions the calculations, and whether the fee is in the quote or billed to you. |
| Inspection fees | Who applies, who pays, and what happens if an inspector asks for extra work. |
| Units and appliances | Whether the price is supply and fit, or fit only against a kitchen you buy. |
| Tiling and floors | Whether the materials are a provisional sum, and at what price per square metre. |
| Making good | Whether walls, floors and ceilings are left ready to paint or left as they fall. |
| Decoration | Almost always excluded. On a whole-house job it is a trade in its own right. |
| Final clean | Builder’s clean or nothing. There is a real difference and it is a day of somebody’s time. |
What each input means
- Your allowance
- What that item would cost you to buy separately, as you would actually pay it, tax included if tax applies. It is used for every quote that does not include the item, so a single figure keeps the three comparisons consistent. Leave a line at zero and it is ignored entirely, which is the right answer for anything that does not apply to your job.
- Quoted price
- The headline number on the quote, exactly as written, before you adjust anything.
- Tax treatment
- Whether that headline already includes tax. If it does not, the rate at the top of the page is added to it, and to that quote’s provisional sums, so everything stays on one footing. If the quote says nothing about tax, ask. It is the single largest correction on this page and the easiest one to get wrong.
- Provisional sums inside the price
- The total of the placeholder amounts the quote carries for things nobody has chosen yet: a kitchen, a bathroom suite, floor coverings, or an allowance for what might be found under the floor. Enter it on the same basis as the quote, which is why the tax treatment above applies to it too.
- What you expect those to really cost
- Your own figure for the same items, all in, as you would pay it. If you have chosen the kitchen, this is its price. If you have not, use the price of one you would be happy with rather than the cheapest you can find. This is the field that stops a low provisional sum from flattering a quote.
- Weeks on site
- The duration the builder has quoted, not the duration you hope for. It only affects the arithmetic if you have put in a weekly cost, but it is worth recording either way: a quote with no duration in it is a quote with no commitment in it.
- Your cost per week on site
- Rent, storage, eating out, commuting, a second set of bills. Only what the work actually costs you, and only for the weeks it runs. Zero is the correct answer for most single-room jobs.
- Tax rate to add
- Your own local rate, used only on quotes you mark as excluding tax. Nothing is filled in for you, because the right rate depends on the country, the type of work and sometimes on whether the builder is registered.
Mistakes people make comparing quotes
- Comparing headline to headline. The prices answer different questions until you normalise them.
- Assuming the tax position. Ask. It moves a number more than anything else on the page.
- Treating a provisional sum as a price. It is a placeholder that will be replaced by an invoice.
- Giving each builder a different brief. Quotes priced from different conversations cannot be compared.
- Ignoring the exclusions page. It is the most informative part of a good quote.
- Forgetting decoration and making good. Invisible until the end, and then thousands.
- Reading a low quote as a bargain. More often it means a smaller scope has been priced.
- Choosing on price alone. The cheapest builder who does not finish is the most expensive one.
Questions about comparing builder quotes
How do I compare builder quotes fairly?
Write one list of everything the job needs, then read each quote against that list rather than against the other quotes. For anything a quote leaves out, add your own allowance for buying it separately. Replace every provisional sum with the figure you actually expect to spend. Put all the prices on the same tax basis. Only then are the numbers comparable. The headline prices almost never are, because each builder has drawn a different line around the work.
Why are builder quotes so different from each other?
Three reasons, and only the third is about price. The scope differs: one quote includes scaffolding and decoration, another does not. The risk allowance differs: a builder who has priced an old property before carries more contingency inside the number. And the workload differs: a builder with a full order book prices high because they do not mind losing it. A gap of 30% between two quotes for the same words is normal, and most of it is usually scope.
What is a provisional sum in a builder’s quote?
A placeholder for work that cannot be priced yet, such as a kitchen you have not chosen or a floor nobody has lifted. It sits in the total and looks like a price, but it is a guess that will be replaced by an invoice. Two quotes carrying different provisional sums for the same item are not comparable until you substitute the same realistic figure into both, which is exactly what the provisional sum fields on this page are for.
Should I always take the cheapest builder quote?
Take the cheapest quote that is genuinely for the whole job, which is often not the lowest headline. Once the missing items are added back and the provisional sums are made real, the order changes more often than not. And a quote well below the others is information: it usually means the builder has read the scope differently, and it is worth asking which parts they have not included before treating it as a bargain.
What is usually left out of a builder’s quote?
Scaffolding and access, waste removal and skips, site protection, structural engineer fees, inspection or building control fees, kitchen and bathroom units where only the fitting is priced, floor coverings, making good after first fix, decoration, and the final clean. Decoration and making good are the two that catch most people, because they are invisible until the work is finished and then they cost thousands.
Do builder quotes include tax?
Sometimes, and that is the problem. Whether tax is shown, at what rate, and whether the builder charges it at all depends on the country, on the type of work and often on whether the builder is registered above a turnover threshold. Read each quote for the words rather than assuming, and if one is quoted without tax and another with it, you are looking at a gap that is not there. This calculator asks you which basis each quote uses and what your own local rate is, and assumes nothing.
How many builder quotes should I get?
Three is the usual advice and it holds up, because two quotes give you no way to tell which one is the outlier. Give all three the same written scope, in the same words, and ask each to state clearly what is excluded. Quotes priced from different conversations cannot be compared no matter what you do to the numbers afterwards.
Should the length of the job change which quote I take?
If you are paying for somewhere else to live, or storage, or eating out, then yes, and it can be decisive. Four extra weeks at a real cost of €400 a week is €1,600 that belongs in the comparison. Put your own weekly figure in and the calculator adds it to each quote in proportion to the weeks that builder has quoted. Leave it at zero if the work does not displace you.
What should be in a written builder quote?
The scope in enough detail that you can tell what is not in it, a list of exclusions, how provisional sums and prime cost items will be settled, the tax position, the payment stages and what triggers each one, the start date and the expected duration, who arranges inspections, who removes waste, and what happens when something is found behind a wall. A quote that is one number and one paragraph is not a quote, it is an opening position.
Does this calculator send my quotes anywhere?
No. Every figure stays in your browser. Nothing is uploaded, stored or logged, there is no account and no email address is asked for. Close the tab and it is gone.
Choosing the builder is the easy day
This page settles which quote to accept and then forgets it, which is the right shape for a calculator and it stays free. The harder question starts the week after: what has actually been spent, which variations were agreed and at what price, whether an invoice has been paid twice, and how much of the contingency is left in month five. The Home Renovation Budget Tracker is the spreadsheet for that part. Approved change orders revise the budget line they hit, the contingency meter turns amber at 25% remaining, the quote tab ranks bids on true all-in cost the way this page does, and a duplicate invoice reference gets flagged. One .xlsx file, six tabs, no macros, €13 once.
See the budget tracker