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Today's Gardens Project Planner

Lawn levelling calculator and method

https://todaysgardens.org/lawn-levelling-calculator/ Planning estimate — generated in your browser and not stored.

Levelling a lawn starts with measuring how deep the dips actually are: shallow ones can be top-dressed and grown through, deeper hollows need the turf lifted and filled underneath. This tool quantifies the material for either approach.

What are you levelling?

Top-dressing a whole lawn, filling a handful of dips, or taking material off in one place and adding it in another.

Area to fill

Fill depth

An average across the whole area, not the depth of the deepest dip. Top-dressing is usually a few millimetres at a time.

Low spots

One row per dip. Each row has its own area and its own average fill depth, and each is reported separately.

Square metres only, so there is no unit to misread.

Your own name for this section, such as Back lawn. It changes no arithmetic.

Area to cut

The high ground you are taking material off. Reported separately from the fill.

Square metres only, so there is no unit to misread.

Cut depth

Assumptions

Applies to fill only. A removal quantity gets no allowance.

Calculations run in your browser. Enable JavaScript to use this calculator.

Your estimate

Worked example — not your result

A 40 m² lawn top-dressed to an average fill depth of 15 mm.

600 litres (L) of fill material

Fill volume
0.600 m³
Area being treated
40.00 m²
Assumptions in this example
Average fill depth 15 mm
Overage not entered — no allowance added
Bag size not entered — no bag count shown
Bulk bag size not entered — no bulk bag count shown

This is an example, not your result. It matches golden vector L1 in the calculation methodology. Enter your own measurements and select Calculate.

How to level a lawn

Levelling starts with measurement, not material. Lay a straight edge or a taut string line across the dips and measure down to the surface: that number decides the method. Shallow hollows can be filled from above and grown through. Deeper ones cannot — bury living grass under 50 mm of soil and it dies, leaving you with a flat patch of bare earth.

  1. Assess. String line and a rule across each dip. Note the depth of each one rather than an impression of the lawn as a whole.
  2. Mark the low spots. Canes or a line of sand. Do this before you start moving material, because a half-filled lawn all looks the same.
  3. Shallow dips — top-dress. Under roughly 25 mm, spread a sandy top-dressing in thin layers, work it in with the back of a rake, and let the grass grow through. Several light passes over a season beat one heavy smothering.
  4. Deeper hollows — lift and fill. Cut an H through the turf, peel the two flaps back, fill and firm the soil underneath, then lay the turf back and press it down.
  5. Firm. Tread or roll lightly. You are closing air pockets, not compacting the ground.
  6. Re-level and check. String line again. Expect to repeat: settlement over the first few weeks reveals what you missed.
  7. Aftercare. Keep the surface damp while the grass knits back together, and keep off it until it has.

Top-dressing after aerating

Levelling and aeration belong together: spiking the lawn first gives the top-dressing somewhere to go, rather than sitting in a layer on the surface.

The lawn care planner will tell you whether the month and the conditions suit aerating first. The compost calculator works out the organic matter for a top-dressing mix, and the topsoil calculator handles the bulk order if the volume is large.

Why cut and fill are never netted

If you enter both, this tool reports two separate figures and refuses to subtract one from the other. Half a cubic metre out of a high spot is not half a cubic metre of usable fill: it comes out mixed with turf, thatch and roots, it needs somewhere to go, and it is rarely the graded material you want to place back under a lawn. Netting them to zero would produce a tidy number and a job you cannot actually do.

Ground preparation checklist

This prints with the record, so you can work down it on site.

  1. String line set up and dip depths written down.
  2. Low spots marked on the ground.
  3. Material ordered against the figure this tool gave, with the assumptions noted.
  4. Access checked: where the delivery lands and how it reaches the lawn.
  5. Turf lifted where dips exceed roughly 25 mm.
  6. Fill placed in layers and firmed, not tipped and raked flat.
  7. Turf relaid, butted tight, and pressed down from a board.
  8. Surface kept damp; lawn kept off until it has knitted.
  9. Re-checked after two to three weeks and topped up where it settled.

How this figure is worked out

Every step is arithmetic you can repeat by hand. Full precision is kept through the calculation and rounded once for display.

Formulae used on this page
Step Formula
Net volume net volume m³ = net area m² × depth m
Gross volume after overage gross volume = net volume × (1 + overage % ÷ 100)
Bag count bags = ceiling(gross litres ÷ bag litres)
Bulk bag count bulk bags = ceiling(gross m³ ÷ bulk bag m³)
Low spot fill volume spot volume m³ = spot area m² × average fill depth m
Cut volume cut volume m³ = cut area m² × average cut depth m

The calculation methodology sets out every formula, bound and rounding rule this site uses.

Sources

SourceRHS — Lawn Care in Autumn

https://www.rhs.org.uk/lawns/autumn-care

checked 6 August 2026. Source key rhs-autumn-care.

  • The mild, damp conditions of early autumn suit this maintenance, and the key tasks are best done in September or October — though not all of them are needed every year.
  • Raking or scarifying removes thatch, which helps water reach the soil and improves air circulation between the grass plants.
  • The field test: if you cannot see the soil between the blades of grass, the lawn would benefit from scarifying.
  • Rake vigorously with a spring-tined rake, aiming to reduce loose debris without uprooting the grass, then compost what comes out.
  • Aerating improves the movement of air and water among the grass roots. Spike with a garden fork, holes 10–15cm apart, as deep as the tines will go, working the fork back and forth to enlarge them.
  • On a large lawn, concentrate on the most worn or compacted areas, or aerate a different area each autumn.
  • For most lawns aerating every two to three years is adequate; on clay or waterlogged soil a hollow-tined aerator is better, every three to four years.
  • Top-dressing is the next step after aerating: six parts sharp sand, three parts loam and one part well-rotted compost or soil improver, raked into the holes. It is particularly useful on heavy soil.