Sold by the square metre, but the entrance does not know how long it is

The driveway is the outdoor work with the simplest price list — so many square metres, so much per metre — and the most lopsided quote there is. Because two items do not live in the square metres: the excavation with its sub-base, which under the paving is often worth as much as the paving itself; and the entrance — the connection to the road, the edging, the gullies, the gate threshold — which costs the same on the 30-square-metre layout and on the 240 one. This calculator breaks the quote into its three forces — surface, sub-base, entrance — and sums it up in two honest numbers: the effective square metre and the index ι, how many times the total exceeds the surface-only bill.

The formula: surface, sub-base and entrance

The model is the decomposition of the horizontal worksite. The surface bill is A·c: the area times the cost per square metre of the finished paving — material and laying, from asphalt to pavers to stone. On that bill acts the surcharge s for excavation and sub-base: near zero on ready ground, above 40% with slope, drainage or soft ground. Outside the product stays the fixed cost F of the entrance: the fixed cost disguised as an accessory, fifth appearance of the geometry — the fence gate, the deck railing, the chimney head, the pool plant room, and now the road connection. The index ι = C/(A·c) is dimensionless and works in any currency.

The scale of the area: the short driveway pays the long one's entrance

The table grows the layout with everything else held equal (60 per m², sub-base 20%, entrance 1,500):

On the short layout the entrance is worth four tenths of the price and the effective square metre doubles the list; on the long forecourt it dilutes until it disappears. It is the driveway's honest paradox: the short layout pays the dearest metre — because connection and gullies do not know how many metres stand behind them.

A complete numerical example

Typical driveway: 60 m² — twenty metres by three — at 60 per square metre of finished paving, excavation and sub-base declared at 20%, a 1,500 entrance across connection, edging and gullies. The surface bill is 60 × 60 = 3,600; the sub-base brings it to 4,320; the entrance closes at 5,820. The index is 5,820 / 3,600 = 1.62: the effective square metre is 97 — not the list's 60 — and the entrance weighs 25.8%. Whoever compares two quotes «at 55 and 65 per metre» without reading sub-base and entrance is comparing the wrong item.

How to read the quote index

The four bands tell four worksites. Below 1.25 you buy square metres of paving: ready ground, simple entrance — the most comparable quote. Between 1.25 and 1.5 the quote is well grounded: the physiology of the driveway without surprises. Between 1.5 and 1.9 the sub-base raises its voice: excavation and off-surface items are a real slice — survey territory. Above 1.9 the driveway is a miniature road worksite: slope, drainage, ancillary works. No band is «wrong»: the index says where to point the lens before signing.

The cost per square metre: what it really contains

The variable c sums up the material choice, and it is as wide as the market: asphalt is the fast economical one of cold climates; concrete follows with its reinforced slab; pavers buy beauty and piece-by-piece repairability; stone and outdoor porcelain play in the high band; gravel opens the list from below. Inside c live the material and laying of the finishing layer. Outside stays what cannot be seen: two «60 per metre» with different thicknesses or bedding sands are not the same price — and the twin rule holds here too: the lowest square metre is almost never the cheapest driveway to own.

The sub-base: the invisible half that decides the lifespan

The variable s is the worksite that will never be seen again: box excavation, geotextile, hardcore compacted in layers, falls for the water. It is the item that produces the driveway's two opposite pathologies: the cracked one, where the sub-base was saved on and the frost or the removal lorry wrote it on the surface; and the golden one, where difficult ground — water table, clay, slope — demanded drainage and road-grade thicknesses. The surcharge is discovered at the survey, not on the phone: it is why two gardens equal on paper produce quotes a third apart.

International perspective: square feet, climates and the same decomposition

The driveway is universal, the conventions are not. North America measures in square feet (multiply by 0.093 for square metres) and lives the seasonality of asphalt — laid hot, laid in summer; Northern Europe digs frost-proof sub-bases that elsewhere would be oversized; the South works on storm drainage. Everywhere the bill has this model's three items — surface, sub-base, entrance — and the index ι compares quotes from different markets on the same scale, because a ratio needs neither exchange rate nor climate.

Limits of the model and correct use

The model photographs the standard driveway: it does not cover retaining walls, lighting, motorised gates nor permits where required — items that add to the total, not hide in the square metre. The area is the truly drivable one: curves and manoeuvring widenings are measured, not guessed. And the price is half the story: the paver calculator counts pieces, sand and hardcore for the DIY route, and the excavation cost calculator isolates the earthworks item when the ground is the real culprit — because a driveway paid right but laid on the wrong sub-base is still a quote that cracks.

The scale of the sub-base: from ready lawn to sloping worksite

The table raises only the excavation-and-sub-base surcharge, surface and entrance held still (60 m², 60 per m², entrance 1,500):

Every 20 surcharge points move the total by 720 — a fifth of the surface bill — and climb the index by almost exactly one band: the ready lawn is a well-grounded worksite, the sloping 80% garden is already past 2.2. The same driveway, five prices: it is the ground that decides, before the price list does.

Reading the scale: the sub-base multiplies only the surface

There is a counter-intuitive detail in the entrance column: while the excavation gets dearer, the entrance share falls — from 29.4% to 18.8%. Not because the entrance costs less, but because the total grows and the fixed part dilutes. It is the structure of the formula made visible: the surcharge s multiplies only the surface bill, never the fixed part — difficult ground does not make the road connection more expensive. For the quote reader it is a quick test: if an offer with a difficult worksite also raises the entrance items «for complexity», that complexity has been counted twice.

The scale of the entrance: from simple connection to monumental gateway

The table raises only the entrance fixed cost, surface and excavation held still (60 m², 60 per m², sub-base 20%):

Between 1,000 and 6,000 lies a whole world: the flush connection with two kerbs on one side; the rebuilt level, the cross drainage channel, the stone threshold and the widened gateway on the other. The surface is the same, the total climbs 94% — and not one more square metre to drive on.

The three heavy rows: when the entrance commands

The last three rows of the scale light up the 30% threshold signal: from 2,500 up the entrance is worth 36.7%, 44.8% and finally 58.1% of the total — more than half the price standing on the first two metres. It is the mirror of the first table: there it was the short layout making the entrance weigh by geometry, here it is the rich gateway doing it by choice. The practical difference is all there: geometry is not negotiable, the specification is — and it is the first item to reread when the quote exceeds the budget, because almost everything living in the entrance can be simplified or postponed, while nobody re-paves halfway.

From quote to worksite: the sequence that protects the budget

The right order is a defence of the wallet. First, the layout: length, width and level decide excavation and entrance more than any negotiation. Second, the survey: the surcharge s is discovered on site — the serious contractor declares it item by item, not spread into the square metre. Third, the specification in three blocks: surface, sub-base, entrance — the calculator's same three — because two close totals with different blocks are two very different driveways. Last, the signature: with the index ι computed on every offer, the «incomprehensibly» distant quotes become almost always explainable — and the inexplicable ones become questions to ask before, not cracks to pay for after.

Typical mistakes and how to avoid them

Four recurring traps. Comparing bare square metres: the «60 per metre» without a specification says nothing about thicknesses or sub-base — compare the index, not the list. Saving below: the skimped sub-base is invisible at handover and visible by the second winter; lifespan is bought below, not above. Narrowing to fit the budget: the entrance stays, the saving is less than proportional — and below 2.5 usable metres you pay in wing mirrors. Forgetting the water: the 1-2% fall and the gullies are not an optional of the specification but the difference between a driveway and an involuntary pool at the first storm.

Frequently asked questions

How much does paving a driveway cost?

With the decomposition C = A·c·(1+s/100) + F: the square metres times the cost of the finished paving, surcharged by excavation and sub-base, plus the entrance fixed cost. With 60 m² at 60 per metre, sub-base at 20% and a 1,500 entrance, the total is 5,820.

What is the driveway quote index?

It is the ratio ι = C/(A·c) between the total and the surface-only bill. Below 1.25 you buy square metres of paving; between 1.5 and 1.9 the sub-base raises its voice; above 1.9 the driveway is a miniature road worksite — slope, drainage, ancillary works.

Why does a short driveway cost more per square metre?

Because the road connection, edging, gullies and threshold cost the same on 30 and on 240 m²: on the short layout the entrance is worth 41% of the price and the effective metre doubles the list. It is the fixed cost disguised as an accessory — the entrance does not know how many metres stand behind it.

What does the cost per square metre include?

Material and laying of the finishing layer: asphalt, concrete, pavers, stone or gravel. Two «60 per metre» with different thicknesses, bedding sands or sub-bases are not the same price: the specification is read layer by layer, just like the entrance.

How much does excavation affect the driveway price?

It is the model's surcharge s: near zero on ready ground, 20% for the ordinary worksite, above 40% with slope, water table, clay or drainage. It is the invisible half of the work — and it is discovered at the survey, not on the phone: two gardens equal on paper can be a third of the price apart.

Asphalt, concrete or pavers for the driveway?

Three bands of the same variable c: asphalt is the fast economical one, concrete the jointless slab, pavers buy beauty and piece-by-piece repairability, stone plays in the high band. The index ι stays comparable across all: c changes, the structure of the count does not.

What does the entrance fixed cost include?

The connection to the public road (ramp and level adjustment), the containment edging, the gullies with their grates, the gate threshold. It is the item that does not scale with the square metres — and the one dominating the short layout's quote.

What slope must a driveway have?

The 1-2% cross fall to shed water is the physiological minimum; above 12-15% longitudinal the ramp demands anti-slip finishes and, in cold climates, becomes the critical ice spot. Steep slope ends up in the surcharge s: more excavation, more drainage, more worksite.

Does the calculator work with square feet?

Yes, converting: 1 square foot = 0.093 m², so a 600-square-foot driveway is about 56 m². The index ι changes with neither unit nor currency, because it is a ratio: just use area and cost in the same family of units.

How long does a paved driveway last?

It depends on the sub-base more than on the finish: well-laid asphalt lasts 15-25 years, concrete and pavers over 25 — but any finish on a skimped sub-base cracks within a few winters. Lifespan is bought below, not above: that is the meaning of the surcharge s.

What is NOT included in the computed cost?

Retaining walls, lighting, the gate and its automation, permits where required. The model photographs the standard driveway: surface, sub-base and entrance — the rest is added item by item.

Is a narrower driveway worth it to save money?

Less than it seems: the entrance stays, so cutting metres raises the effective square metre — and below 2.5 usable metres the daily manoeuvre is paid in wing mirrors. The calculator's area scale shows exactly what each removed metre returns: often less than it costs in use.

Updated July 2026