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How do you work out how much carpet you need?
Measure each room at its longest and widest points, then fit that rectangle onto the roll widths the carpet comes in, allowing for pile direction, joins and trimming. The amount you buy is set by the roll, not the floor area, so ask each shop to show its cutting plan.
Last reviewed:Why is a carpet calculator only a starting point?
A simple carpet calculator multiplies length by width and give you an area. That tells you how big the floor is, but not how much carpet you will be charged for. Carpet is cut from a roll of a fixed width, so the amount you buy depends on how your room fits onto that roll.
Two rooms with the same floor area can need very different amounts of carpet. A long, narrow hall cut from a wide roll leaves a big offcut. A room just a little wider than the roll needs a second strip and a join. A room with a deep bay window may be measured as a larger rectangle than its floor.
This guide sets out a method you can use at home to check a shop's figure. It does not print a price per square metre, because carpet prices vary hugely by product and the fitting depends on the room. What it gives you is a way to make sure every quote is for the same amount of carpet.
QuoteZila starts in Cheshire, with Crewe, Nantwich and Sandbach first, and anyone in the UK can post a carpet job. Our flooring fitters page covers the trade.
How do you measure a room for carpet?
You need a tape measure, a pencil and a rough sketch of the room seen from above.
Measure at the widest and longest points. Walls are rarely perfectly square. Measure the length in two or three places and the width in two or three places. Use the largest figure each way.
Go into the doorway. Carpet usually finishes under the door, at the threshold strip. Measure to the middle of the doorway, not to the face of the wall.
Include bays, alcoves and recesses. Measure each one and draw it on your sketch. A bay window is often treated as part of a bigger rectangle, because it is cut from the same piece.
Mark fixed items. Fitted wardrobes, a fireplace hearth, radiator pipes and floor vents all change the cutting. Show them on the sketch.
Write down what is on the floor now. Old carpet, underlay, gripper, vinyl or floorboards all affect the job, even though they do not change the size.
If the room has stairs off it, measure the stairs separately. Our measuring stairs for carpet page explains treads, risers and winders.
How do you turn the measurements into a quantity?
Start with the roll widths the carpet you like comes in. Ask the shop, or read the product label. Some ranges come in more than one width, and the right one depends on your room.
If the room is narrower than a roll width, you need one piece, as long as the room and as wide as the roll. The strip you cut off the side is waste unless it can be used somewhere else.
If the room is wider than the largest roll, you need two or more pieces joined together. The join is called a seam. Where it goes matters: across a doorway or a main walking line it will wear and show.
Allow for trimming. A fitter needs a little extra at every wall to cut a clean edge. This guide does not print a margin figure, because it depends on the fitter and the room. Ask them what they allow.
Check pile direction. The pile of a carpet usually lies one way, which changes how the colour looks from different angles. Every piece in a room, and usually across connected rooms, should run the same way. That can rule out turning an offcut round to fill a gap.
Patterned carpet needs pattern matching. Each piece has to line up with its neighbour, so more is needed than for a plain carpet of the same size. Ask how much extra the shop has allowed and why.
Once you have the shape on paper, the quantity is the length of roll needed to cut every piece in the right direction. That is the number a shop's quote should match.
What should a carpet quote list?
A clear quote shows the quantity as well as the price. Without the quantity, you cannot tell whether one shop has allowed more carpet than another.
| Line | What a clear quote says | Why it changes the cost |
|---|---|---|
| Carpet | Product name, roll width and length of roll needed for each room | The roll, not the floor area, sets how much you buy |
| Joins | How many seams, and where they will go | More pieces mean more carpet and more fitting time |
| Underlay | Product name and area covered | A different underlay is a different price, even if the carpet is the same |
| Gripper and door bars | Length of gripper and number of threshold strips | Each doorway needs a finish where the carpet meets the next floor |
| Uplift of old floor | Whether old carpet, underlay and gripper are lifted and taken away | Removal is labour and waste, and must be dealt with properly [S3] |
| Furniture | Whether the fitter moves it, or expects the room empty | Moving a full bedroom takes time |
| Doors | Whether doors will be trimmed to clear the new carpet | A thicker carpet and underlay can stop a door closing |
| VAT | Included or added. Registration is required above £90,000 of taxable turnover in the last 12 months [S2] | Comparing a total with VAT to one without is not like for like |
| Payment | When money is due, any deposit, and a receipt [S1] | Protects you if something goes wrong |
A quote that covers every line may look higher than one that covers half of them. That does not make it the dearer job.
What makes the quantity go up?
Room shape. L-shaped rooms, bays, chimney breasts and long corridors all add offcuts.
Roll width choice. If the carpet you like only comes in one width, and that width suits your room badly, you may pay for a lot of waste. A different carpet in a better width can be cheaper overall even if its price per metre is higher.
Pile and pattern. Pile direction and pattern matching both stop offcuts being turned round to fill gaps.
Splitting rooms. Pricing each room separately can mean buying a full width for a small room that could have been cut from another room's offcut. Ask the shop to plan the cuts across the whole order.
Stairs and landings. These are measured differently and often cut from their own piece. The carpet for stairs guide explains what changes that part of the price.
What else is in the price besides the carpet?
The amount of carpet is only one part of a quote. The fitting labour, underlay, gripper and door bars all add to it.
Preparation. A concrete floor with dips, or floorboards that squeak, may need work before the carpet goes down. That is a separate task, and a good fitter will say so.
Taking up the old floor. GOV.UK's waste code says that when a tradesperson does work on your property, they are responsible for the waste they produce, including its transport and disposal, and its cost should be included in what they charge [S3]. If you lift the old carpet yourself and ask someone to take it away, the code says you must take all reasonable measures to make sure it goes only to an authorised person [S3].
Doors. New carpet and underlay can raise the floor. Ask whether trimming doors is included.
Carpet fitting costs covers the fitting side in more detail, and carpet installation explains what happens on the day.
How do you compare carpet quotes fairly?
Send every shop or fitter the same thing: your sketch, your measurements, the carpet you want, and photos of the room and the doorways. Ask them to measure before anything is cut, and to put their own quantity on the quote.
Citizens Advice suggests trying to get written quotes from at least 3 different traders, and says some traders charge for quotes, so ask about this first [S1]. It explains that a quote is a fixed price, while an estimate is just a rough guess and you might end up paying more [S1]. Once you say yes to a quote, it is a binding agreement, whether it is written down or not [S1].
If a shop asks for a deposit to pay for the carpet, Citizens Advice suggests offering to buy materials yourself instead, so at least you own them if something goes wrong [S1]. For a long job where a deposit cannot be avoided, it says not to agree to more than 25%, and always to get a receipt [S1].
If the fitting goes wrong later, Citizens Advice says the Consumer Rights Act 2015 requires services to be provided with reasonable care and skill [S4]. A written quote with the quantity on it makes it much easier to show what was agreed.
What if you plan to fit it yourself?
A small, square room with a sound floor is the most realistic DIY carpet job. Laying carpet walks through the stages. Even then, measuring carefully and buying from the right roll width will save more money than any other step.
For anything with a join, a patterned carpet, or stairs, a fitter is usually the safer choice. A badly placed seam or a short piece cannot be fixed after the carpet is cut.
Jobs you might post
These are examples, not taken from real job posts.
- "Two bedrooms and a landing. I have measured and drawn a plan. Please check my figures and quote to supply and fit, with the roll width and quantity written on the quote."
- "Lounge with a bay window, wider than most roll widths. Please say where the join would go and quote for carpet, underlay and fitting."
- "I have bought the carpet already and want a fitter to measure the offcuts and fit it in the hall and a box room."
Posting a carpet job
Your sketch and photos of the room are the most useful things you can add. Your job goes to up to five matched local businesses [QZ2]. QuoteZila is free for customers and local businesses [QZ1].
Honest status: QuoteZila is new. We're starting in Cheshire, beginning with Crewe, Nantwich and Sandbach, and growing area by area. Anyone in the UK can still post a job or register a business. How fast you get quotes depends on how many local businesses have joined near you. Businesses can register and receive jobs straight away. We don't check insurance, qualifications or registrations, so please check these yourself before you hire.
Posting a job is not open yet
Questions about working out carpet quantities
Why does the shop want to sell me more carpet than my floor area?
Because carpet comes off a roll in fixed widths. If your room is narrower than the roll, the strip left along one side is waste you still pay for. If it is wider, you need a second piece and a join. The shop's figure should come from a cutting plan, and you can ask to see it.
Can I use an online carpet calculator instead of measuring?
An online calculator is a useful first check, but it only knows the numbers you type in. It cannot see a bay window, a chimney breast or which way the pile should run. Use it to compare, then let the fitter measure before anything is cut.
Do I need to measure for underlay and gripper too?
Underlay is usually priced on the room's area, because it can be joined anywhere and is not patterned. Gripper rod goes round the edges, so its length follows the walls, minus doorways. Ask for both as separate lines so you can see how much of each is included.
Is it cheaper to have one carpet through several rooms?
Sometimes. Cutting several rooms from one roll can use offcuts from a big room for a small one, such as a cupboard or a landing. Ask the shop whether they have planned the cuts across all the rooms together, or priced each room on its own.
Does VAT change the price?
It can. A business must register for VAT if its taxable turnover for the last 12 months goes over £90,000. Ask each shop or fitter whether VAT is included in their total, so you compare like with like.
How many quotes should I get?
Citizens Advice suggests trying to get written quotes from at least 3 different traders before you decide on one. Give each the same room measurements and the same carpet choice, so the quotes can be lined up.
Does QuoteZila check flooring fitters?
No. We don't check insurance, qualifications or registrations, so please check these yourself before you hire. You can report a quote or a business from your job page.
This page is general information, not professional or legal advice. QuoteZila does not check Gas Safe, WaterSafe, NFRC, NICEIC or other registrations against the register on your behalf: look them up yourself.
Part of Cost guides. All services
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Related pages
- Carpet Fitting Cost: What Changes the Price. What changes the cost of carpet fitting: room size and shape, stairs, underlay, gripper, lifting old flooring, floor preparation, furniture, doors and VAT.
- Carpet for Stairs: What Changes the Price. What moves a stair carpet quote: straight steps or winders, fitted carpet or a runner, open sides, the landing and uplift of the old carpet. No price per step.
Sources
- QZ1: QuoteZila product fact. QuoteZila home and FAQ copy.
- QZ2: QuoteZila product fact. QuoteZila FAQ How does getting quotes work.
- S1: Before you get building work done, Citizens Advice. Accessed 2026-11-01. https://www.citizensadvice.org.uk/consumer/getting-home-improvements-done/before-you-get-building-work-done/
- S2: Register for VAT, GOV.UK. Accessed 2026-11-01. https://www.gov.uk/register-for-vat
- S3: Waste duty of care: code of practice, GOV.UK (Defra). Accessed 2026-11-01. https://www.gov.uk/government/publications/waste-duty-of-care-code-of-practice/waste-duty-of-care-code-of-practice
- S4: If you're unhappy about poor service, Citizens Advice. Accessed 2026-11-01. https://www.citizensadvice.org.uk/consumer/somethings-gone-wrong-with-a-purchase/complain-about-a-service/