The grass is bought by the square metre, the base is not

Anyone asking for an artificial grass quote looks at the price of the roll — and discovers the real bill is played elsewhere. The price has three souls: the laid turf — yarn, weed membrane and labour — paid per square metre; the base preparation — dig, draining screed, compaction — inflating the price as a percentage, the item that never shows in photos; and the fixed items quotes put at the bottom: disposal of the old surface or the existing lawn, transport, edges and seaming — items that do not count the metres and that, on a small courtyard, weigh as much as half the grass. This calculator reassembles the three souls and judges them with a dimensionless metric: the quote index, the total divided by the bare turf.

The formula: the bare turf and its two tolls

The model is the structure of every serious quote: C = A·c·(1 + p/100) + F. The bare turf A·c is the area times the cost of the laid synthetic; the preparation p scales it by the real base; the fixed cost F is added at the end, indifferent to the metres. From here the two reading metrics: the index ι = C/(A·c), saying how many times the total exceeds the bare turf, and the share q = 100·F/C, saying how much of the price is not grass. The first compares quotes with each other; the second tells where the money goes.

The area scale: the small courtyard pays for the truck

Turf at 40 per square metre, preparation at 30 percent, fixed items 800; only the area grows:

The reading is all in the last columns: on the 10-square-metre courtyard, disposal and fixed items are 60.6 percent of the price and every metre costs 132; on the condominium the same fixed items slide to 7.1 and the metre drops to 56. And the patio row touches an exact frontier: index 2.30 on the nose — the doorway of the band where you buy excavation, not grass. The per-square-metre cost of synthetic turf does not exist: only your garden's does.

A complete numerical example

The typical home garden: 40 square metres, mid-range turf at 40 per laid square metre, preparation at 30 percent on reasonable ground, 800 fixed for old lawn disposal, transport and edges. The bare turf is 40 × 40 = 1,600; preparation takes it to 1,600 × 1.30 = 2,080; the fixed items close at 2,880. That is 72 per effective square metre — against the 40 list price — with index 1.80 and fixed share at 27.8 percent: a quote within physiology, where the turf commands and base and fixed items follow in proportion.

How to read the quote index

The four bands of the index tell what you are really buying. Below 1.55 the large garden dilutes the worksite: the total travels close to the bare turf and the comparison is played on the yarn. Between 1.55 and 1.90 is the well-proportioned synthetic lawn: the physiology of the home garden. Between 1.90 and 2.30 the base weighs as much as the turf: the preparation should be detailed item by item. From 2.30 upward you are buying excavation, not grass: the geometry of small courtyards and bases to rebuild — where the right question is whether a few more metres at marginal cost change the bill more than any discount.

The turf: where the differences you see for years live

The variable c is the visible heart of the quote. At the bottom of the range, 20-30 per laid square metre, live the short, budget yarns: honest on a terrace, suffering in a lived-in garden. In the middle, 40-50, the serious synthetic: 30-40 millimetre pile, dual-blend yarn, UV resistance guaranteed for years — the warranty that separates the lawn that lasts from the lawn that fades. At the top, 60-80, high density and memory fibres that stand back up on their own. The golden rule: yarn is judged by touch and against the light, but its life is decided by the UV certification — the only line of the specification that works every summer day.

The base: the lawn you cannot see

The variable p is the true trade of the installation: synthetic turf lasts as long as its base does. Under the grass work the 8-12 centimetre dig, the weed membrane, the compacted aggregate screed that must drain water like a flat roof: a base that ponds lifts the turf, makes bumps and odours, and one winter of standing water gives back every summer discount with interest. On stable ground the preparation runs 10-20 percent; on real lawn to remove or clay soil it climbs to 50-80. It is the item to have detailed centimetre by centimetre — because that is where two quotes equal outside hide two different gardens underneath.

International perspective: the same grass in every currency

The model is deliberately currency-neutral: enter the costs in your own money and read total and per-square-metre cost in the same unit. Synthetic turf is a global market — the yarns travel from the same plants towards Europe's mild winter gardens and towards North America and arid countries, where artificial lawn is a child of water restrictions and is measured in square feet (1 m² ≈ 10.8 sq ft). Everywhere the base is prepared the same way and disposal does not count the metres. And the quote index is dimensionless: 1.80 tells the same proportion in Milan, Phoenix or Hamburg — the metric that travels without exchange rates.

Model limits and correct use

This is the parametric quote for decorative garden turf: it does not cover sports fields with their performance infills and federation certifications, nor roof gardens on waterproofing membranes — where the base is another trade — nor maintenance: synthetic grass is not watered but it is brushed, and now and then asks for top-up sand. The area is measured on real geometries with roll offcuts; and the lawn is one piece of the outdoor project: the fence cost calculator closes the perimeter of the same garden, and the pergola cost calculator puts a price on the shade the synthetic thanks in torrid summers — because a well-made outdoor space is one single worksite, and fixed costs split across several works weigh half as much.

The preparation scale: the worksite under the grass

A 40-square-metre garden, turf at 40, fixed items 800; only the base preparation grows:

The progression is regular: every twenty points of preparation are worth 0.20 of index — from the stable base at 1.70 to the limit case touching 2.30 on the nose, the same frontier the 20-square-metre patio reaches by another road. And the fixed share falls while everything rises: the dig inflates the proportional part, and the truck — which does not change — weighs ever less in percentage. The practical lesson: the survey with a screwdriver is gold — an hour probing the real base moves the quote more than any negotiation.

The fixed scale: the truck that does not count the metres

The same 40-square-metre garden, turf at 40, preparation at 30 percent; only the fixed items grow:

The first row touches the exact 1.55 border — the doorway of physiology — and the fourth finds 2.30 again by the third road: small area, difficult base or full fixed items lead to the same frontier. From the last three rows the share exceeds 30 percent and the disposal commands the bill: at 2,000 of fixed items, half the quote is not grass. It is not theft — landfill and trips cost — but it is the moment to ask whether the trip can be shared: with the driveway, the neighbour, the new fence — because the truck divided by two is the only discount that takes no quality away.

The exact borders of the bands

The model's frontiers can be touched by hand. The 20-square-metre patio with turf at 40, ordinary preparation and a clean 200 fixed: total 1,240, per square metre 62, index exactly 1.55 — the border belongs to the physiology band, not to dilution. The same patio with turf at 50, half the base to rebuild and 400 fixed: total 1,900, 95 per metre, index 1.90 exact — the first step into the band where the base weighs as much as the turf. And the 10-metre courtyard at 50 with preparation at 40 and 300 fixed closes the picture: a round 1,000 total, 100 per square metre, index 2.00 and fixed share at exactly 30.0 percent — the first millimetre of the territory where the disposal commands; one hundred less of fixed items, and the share slides to 22.2 in the ordinary band.

Terrace, garden, courtyard: three typical worksites

The terrace: draining turf laid on the existing membrane without piercing it, light preparation at 10-20 percent, small fixed items — the index travels low and the comparison is played entirely on the yarn. The home garden: 30-60 square metres with the old lawn to remove, dig and aggregate — the profile of our example, index between 1.7 and 2.0, where the base specification decides the lifespan. The small courtyard: 10-20 metres between walls, narrow access, the truck costing as for a hundred metres — indexes above 2.3 are physiological, the territory where you buy excavation and logistics before grass. Three scales, three weights of the same four levers: the calculator exists to see them before signing.

How to lower the bill without losing lawn

The good levers sit at the sides of the formula. On the turf: the geometry of the rolls — rolls come in fixed widths, and a garden drawn on commercial widths wastes less offcut than one carved on a whim. On the preparation: do not pay for the dig you do not need — an already stable base asks only levelling and membrane, and the difference is worth twenty points of index. On the fixed items: the shared trip — disposal and transport bundled with other outdoor works halve the item that does not count the metres. There is only one bad lever: saving on drainage — standing water under the turf gives back every discount in one winter, with interest and with odours.

The mistakes of the DIY quote

The first mistake is multiplying metres by roll price: the bare turf ignores base and fixed items, and the real quote arrives nearly double. The second is judging the synthetic by the photo instead of the specification: density, blend and UV warranty do not show in a picture — and they are what remains after three summers. The third is ignoring the base: the grass is laid on a worksite, not on a lawn — who does not dig today redoes everything tomorrow. The fourth is forgetting the pile direction: rolls are all laid the same way, and a patchwork garden shows at every sunset. And the fifth is comparing quotes with different perimeters: the quote index exists precisely to make commensurable totals that look equal outside and are not underneath.

Frequently asked questions

How much does installed artificial grass cost?

It hangs on four levers: area, turf cost, base preparation and fixed items. The typical garden — 40 square metres at 40 with 30 percent preparation and 800 fixed — closes at 2,880, that is 72 effective per square metre. The 10-metre courtyard climbs to 132 per metre: the unit cost depends on the garden, not the roll.

What is the quote index?

The total divided by the bare turf A·c of the laid synthetic alone: a dimensionless metric that compares quotes. Below 1.55 the large garden dilutes the fixed items; between 1.55 and 1.90 the physiology; between 1.90 and 2.30 the base weighs as much as the turf; above 2.30 you are mostly buying excavation and disposal.

What does base preparation include?

The 8-12 centimetre dig, the weed membrane, the compacted aggregate that drains like a flat roof. On stable ground it runs 10-20 percent; on real lawn to remove or clay it climbs to 50-80: the item to have detailed centimetre by centimetre.

Why is the base so important?

Because synthetic turf lasts as long as its base: ponding lifts the turf, makes bumps and odours, and one winter of standing water gives back every discount with interest. Drainage declared in the specification is worth more than ten points of discount on the yarn.

Which turf should I choose?

A 30-40 millimetre dual-blend pile is the standard for a lived-in garden; short budget yarns live well on terraces. The line that counts is the UV warranty: it is what separates the lawn that lasts ten years from the lawn that fades in three.

How much does disposal weigh on the bill?

It is the fixed item that does not count the metres: the truck costs the same for ten metres and for a hundred. In physiology it runs 10-25 percent; above 30 the calculator flags it — typical of small courtyards, where bundling the job with a neighbour or other works changes the bill more than any discount.

Is synthetic grass really maintenance-free?

Free of watering and mowing, yes; free of care, no: it is brushed against the pile, leaves are removed, and the infill sand is topped up now and then. Half an hour a month against the weekly hours of real lawn: little, but not zero.

Does artificial grass get hot in summer?

Yes: in direct sun the surface goes well above real grass. The countermoves: cool-blend yarns, lighter colours, a pass of water in torrid hours and designed shade — a pergola over the synthetic is a marriage that works.

Is drainage needed on a terrace too?

Yes, but it is another trade: on a terrace the draining turf rests on the existing membrane and the water must be guided to the outlets without piercing it. The preparation is lighter than a garden dig, but slope and edges deserve the same seriousness.

Does the calculator work outside Europe?

Yes: the model is currency-neutral and the structure of the bill — turf, base, fixed items — is identical in every market, from European gardens to arid countries where synthetic lawn was born of water restrictions (1 m² ≈ 10.8 sq ft). The index is dimensionless and compares quotes everywhere.

When is the fixed share too high?

Above 30 percent the calculator flags it: typical of 10-20 square metre courtyards. It is not an error — it is the geometry of the truck and the small worksite — but a number to use: a few more metres cost only themselves, and a shared trip halves the fixed cost.

What does the calculation NOT cover?

Sports fields with infills and federation certifications, roof gardens on membranes, residual irrigation for real flowerbeds, maintenance over the years. It is the parametric quote of the decorative lawn: confirmation belongs to the installer on the real survey.

Updated July 2026