Plan a full soil project in one pass — multi-zone layout, soil mix ratios, settling buffer, bag vs bulk cost comparison, truckload planning and a budget reverse-solver. Covers the calculation competitors skip: how much you actually need after settling, and what your money really buys.
- Multi-Zone Planner
- Soil Mix Blender
- Settling Buffer
- Budget Reverse Solver
- Sensitivity Matrix
- Bag vs Bulk Cost
Soil Mix Blender — split any zone into topsoil, compost and sand ▾
Enable to break the total soil volume into a recipe. Most beds use a blend rather than 100% topsoil. The three common ratios are shown below.
Results are at rest
Set your zones, depth and soil mix, then press Calculate Topsoil.
Inputs changed — press Calculate Topsoil to refresh.
Bag vs bulk cost comparison
Depth × area sensitivity (cubic yards)
| Depth | 100 sq ft | 250 sq ft | 500 sq ft | 1,000 sq ft |
|---|
Budget reverse solver — what your money buys
Four Questions Every Topsoil Project Asks
People come to a topsoil calculator with one of four questions. Most tools answer only the first. This one answers all four, in the order they actually matter.
1. How much do I need?
The raw calculation: area × depth. Every calculator answers this. It is the starting point, not the answer.
2. How much do I order?
After settling. Fresh topsoil compresses 10–20% in the first month. Ordering the raw number leaves you short every time.
3. What mix do I actually spread?
Beds rarely need 100% topsoil. Most recipes call for a blend with compost or sand. Splitting the volume before ordering is what most calculators skip.
4. What does my budget buy?
If you have $300 to spend, how much area can you cover? The reverse solver flips the math and gives you the answer.
Topsoil is excavated, screened, loaded, trucked, dumped and spread. Every step aerates it and adds pore space. When you water and walk on it, the air pockets collapse and the layer drops by 10 to 20%. A 4-inch layer measured on the truck often settles to 3.2 to 3.6 inches on the ground. That gap is where most short-order frustration comes from.
Topsoil Depth Guide by Project
The right depth depends on what is growing in it, what is underneath, and how much root space the plant needs. These are the depth bands used by extension services and landscape architects. Depths are always the finished depth after settling.
| Project | Depth (settled) | Notes |
|---|---|---|
| Lawn top dressing | 0.25–0.5 in | Light layer to fill low spots and improve surface |
| New lawn from seed | 4–6 in | 4 in minimum over rough-graded subsoil; 6 in if subsoil is clay |
| Sod installation | 2–4 in | Blend with 4–6 in of existing tilled soil for best rooting |
| Flower beds | 6–8 in | Shallow-rooted annuals and perennials |
| Vegetable garden | 8–12 in | Root crops like carrots need 10–15 in; leafy greens do fine at 8 |
| Raised beds | 8–18 in | Depends on bed wall height; 12+ in for tomatoes, peppers, squash |
| Tree & shrub planting | Hole depth + 6 in | Backfill with native soil, use topsoil as surface layer |
| Fill dirt / grading | As needed | Use unscreened fill for deep lifts; cap with screened topsoil |
| Landscape bed refresh | 2–3 in | Top-up over existing beds without disturbing roots |
Depth is the number to get right, not the formula. Most people who come to a topsoil calculator already know the formula. They are stuck on the depth. The guide above gives a defensible band for every common project. When in doubt, go to the middle of the band and add the settling buffer.
Coverage per Cubic Yard
One cubic yard covers the area below at each depth. Use this to sanity-check the calculator output against your project size.
| Depth | Coverage | Weight (approx.) | Common use |
|---|---|---|---|
| 0.5 in | 648 sq ft | ~1.3 tons | Lawn top dressing |
| 1 in | 324 sq ft | ~1.3 tons | Light top-up |
| 2 in | 162 sq ft | ~1.3 tons | Sod base, thin beds |
| 3 in | 108 sq ft | ~1.3 tons | Bed refresh |
| 4 in | 81 sq ft | ~1.3 tons | New lawn minimum |
| 6 in | 54 sq ft | ~1.3 tons | New lawn preferred, flower beds |
| 8 in | 40 sq ft | ~1.3 tons | Vegetable garden |
| 12 in | 27 sq ft | ~1.3 tons | Raised beds, deep planting |
Weight varies more than volume. Dry screened topsoil sits around 2,600 lb/yd³. Wet, unscreened topsoil can hit 3,000 lb/yd³. That is a 15% swing on the same cubic yardage. Always confirm weight with the supplier if the truck is close to its legal limit.
Topsoil Quality — What to Look For
Volume and depth get you the right quantity. Quality gets you the right results. Three tests determine whether the topsoil you are buying will actually grow anything.
Texture
Moisten a handful and squeeze it. Loam crumbles with a light touch. Heavy clay forms a sticky ribbon; sandy soil falls apart. Ideal loam is roughly 40% sand, 40% silt, 20% clay. If the seller cannot tell you the texture, the topsoil is unknown quality.
pH
Most vegetables and lawn grasses grow best at pH 6.0 to 7.0. Acidic soil locks up nutrients; alkaline soil does the same. Ask for a pH reading or test it yourself with a $15 kit. Lime raises pH; sulfur or peat lowers it.
Organic matter
Good topsoil holds 3–5% organic matter. Below 2% the soil is dead. Above 8% it is closer to compost than topsoil. Ask the supplier for a recent soil test — every commercial yard should have one.
Contamination
Watch for weed seeds, roots, rocks, glass and chemical residue. Screened topsoil removes most of these. Unscreened topsoil is cheaper but can bring weed problems that last years. For vegetable beds, always buy screened.
Dig a hole one foot deep in three or four spots across the project area. Look at where the dark topsoil layer ends and the lighter subsoil begins. That transition depth is the topsoil already present. If it is 4 in and you want 8 in of finished soil, you only need to bring in the difference. This single test saves more money than any calculation.
Worked Examples
Example 1: 1,200 sq ft front lawn at 4 inches
| Step | Calculation | Result |
|---|---|---|
| Raw volume | 1,200 × 4 ÷ 324 | 14.81 yd³ |
| Settling buffer (15%) | 14.81 × 1.15 | 17.03 yd³ |
| Weight (2,600 lb/yd³) | 17.03 × 1.3 | 22.1 tons |
| Bulk cost ($35/yd³ + $120 delivery) | 17.03 × $35 + $120 | $716 |
| Bag cost (1.5 cu ft bags at $5) | 17.03 × 27 ÷ 1.5 × $5 | $1,533 |
| Best price | Bulk delivery | $716 (saves $817) |
Example 2: 200 sq ft raised vegetable bed at 12 inches
| Step | Calculation | Result |
|---|---|---|
| Raw volume | 200 × 12 ÷ 324 | 7.41 yd³ |
| Settling buffer (18%) | 7.41 × 1.18 | 8.74 yd³ |
| 70/30 topsoil/compost split | 8.74 × 0.70 / 0.30 | 6.12 / 2.62 yd³ |
| Topsoil cost ($35/yd³) | 6.12 × $35 | $214 |
| Compost cost ($40/yd³) | 2.62 × $40 | $105 |
| Delivery | — | $120 |
| Total | — | $439 |
Example 3: Budget reverse solver — what $300 buys
| Step | Calculation | Result |
|---|---|---|
| Budget | — | $300 |
| Less delivery fee | $300 − $120 | $180 available for material |
| Cubic yards at $35/yd³ | $180 ÷ $35 | 5.14 yd³ |
| Square feet at 4 inches | 5.14 × 81 | 416 sq ft |
| Square feet at 2 inches | 5.14 × 162 | 833 sq ft |
| Square feet at 6 inches | 5.14 × 54 | 278 sq ft |
Notice the reverse solver in action: $300 covers 416 sq ft at 4 inches, or 833 sq ft at 2 inches, or 278 sq ft at 6 inches. Same money, three different project sizes. This is the calculation nobody does, and it is the one that actually fits a real budget.
Bagged vs Bulk Topsoil
The per-unit price difference is dramatic. The delivery fee is what closes the gap. There is a specific break-even volume where bulk starts winning.
| Volume | Bagged cost (1.5 cu ft at $5) | Bulk cost ($35/yd³ + $120) | Cheaper option |
|---|---|---|---|
| 0.5 yd³ | $135 | $137.50 | Bagged |
| 1 yd³ | $270 | $155 | Bulk (saves $115) |
| 2 yd³ | $540 | $190 | Bulk (saves $350) |
| 5 yd³ | $1,350 | $295 | Bulk (saves $1,055) |
| 10 yd³ | $2,700 | $470 | Bulk (saves $2,230) |
| 20 yd³ | $5,400 | $820 | Bulk (saves $4,580) |
Break-even is roughly half a cubic yard once delivery is included. Below that, bagged topsoil wins on convenience. Above that, bulk wins on price and wins harder with every extra yard. The calculator above shows both totals side by side so you can see your exact break-even point.
Handling Irregular and Curved Beds
Most garden beds are not clean rectangles. Curved borders, kidney shapes and L-shaped lawns all need a measurement method that accounts for the actual footprint.
Break into rectangles
Chop the bed into the largest rectangles you can fit inside it. Calculate each area. This underestimates slightly, which is safe.
Add circles for curves
Approximate curved ends with circles or half-circles. Use π × r² for full circles and half of that for half-circles.
Use triangles for wedges
Angled sections of an irregular bed are triangles: 0.5 × base × height. Add them to the total.
Offset (trapezoid) method
For very irregular shapes, lay a tape along one edge. Measure widths at regular intervals. Average the widths, multiply by the interval length, sum the strips. This is the surveyor's method for curved ground.
When in doubt, over-measure by 5%. Curved and irregular beds almost always end up larger than the initial estimate. Adding 5% to your total area before running the calculator is cheaper than a second delivery.
Common Topsoil Mistakes
Ordering the raw calculation
No settling buffer. You water the soil, it drops 15%, and now you are short by exactly that amount.
Mixing inches and feet
Depth is in inches, area is in feet. The ÷324 shortcut handles both. Forgetting to convert depth to feet first is the most common arithmetic error.
Using fill dirt as topsoil
Fill dirt is cheap, but it has almost no organic matter and often contains rocks and weeds. It is for bulk grading, not for growing.
Ignoring the existing topsoil
If a test hole shows 4 inches of good topsoil already in place, you only need to bring in the difference. Skipping the test hole doubles your order.
Spreading straight topsoil in beds
Most beds perform better with a topsoil/compost blend. Pure topsoil can compact and drain poorly. Mix before ordering.
Not checking truck access
A loaded dump truck weighs 25–30 tons. It needs a wide, firm driveway and room to turn. Confirm access before ordering bulk delivery.
Topsoil specification follows ASTM D5268 (Standard Specification for Topsoil Used for Landscaping Purposes). Bulk density is measured under ASTM D7263. pH and organic matter testing follow ASTM D4972 and ASTM D2974. Compaction testing uses AASHTO T180 (modified Proctor). UK landscape work follows BS 3882 for topsoil specification.
One cubic yard of topsoil covers 324 sq ft at 1 inch, 108 sq ft at 3 inches, 81 sq ft at 4 inches, 54 sq ft at 6 inches or 27 sq ft at 12 inches. One cubic yard weighs about 1.3 tons (2,600 lb). A 40 lb bag is about 0.75 cu ft, so 36 bags equals one cubic yard. Add 15% settling buffer on top of the raw volume. Bulk topsoil at $30–$50/yd³ is roughly 5× cheaper than bagged once delivery is spread across a real order.
People Also Ask
How do I calculate how much topsoil I need?
Multiply the area in square feet by the depth in inches and divide by 324 to get cubic yards. Then add 15% for settling. For a 1,200 sq ft lawn at 4 inches: 1,200 × 4 ÷ 324 = 14.81 yd³ raw, plus 15% settling = 17.03 yd³. Order 18 yards to be safe.
How deep should topsoil be for a new lawn?
4 inches minimum over rough-graded subsoil, and 6 inches preferred if the subsoil is clay or compacted. Blend the topsoil into the top 1–2 inches of existing soil so roots transition smoothly between layers. Deeper than 6 inches is wasteful for grass because most lawn roots stay in the top 4–6 inches.
How many cubic yards of topsoil are in a truckload?
A single-axle dump truck carries 8–10 cubic yards. A tandem-axle carries 12–15. A tri-axle carries 18–20. Weight limits often bind before volume: a tandem truck hauling wet topsoil at 1.5 tons/yd³ hits its 25-ton legal limit at about 16 yards. Always confirm the supplier's actual load size.
How much does a cubic yard of topsoil weigh?
Dry screened topsoil weighs about 2,600 lb (1.3 tons) per cubic yard. Wet or unscreened topsoil can reach 3,000 lb (1.5 tons). Blended garden mix with compost sits around 2,200–2,400 lb. Weight is the binding constraint on most deliveries, not volume.
Is bagged or bulk topsoil cheaper?
Bulk is almost always cheaper once you cross about half a cubic yard. A 1.5 cu ft bag at $5 works out to $90 per cubic yard. Bulk topsoil at $35/yd³ plus a $120 delivery fee works out to $155 for the first yard, then $35 for every yard after. At 5 yards you are paying $295 bulk vs $1,350 bagged — a $1,055 saving.
What is the settling buffer and why do I need it?
Fresh topsoil is aerated during excavation, screening and loading. When you water it and walk on it, air pockets collapse and the layer drops by 10 to 20%. A 4-inch layer settles to about 3.4 inches. Order 15% extra so the finished depth matches what you planned. For raised beds with fluffy blends, use 18–20%.
How much topsoil for a raised garden bed?
Depends on the bed wall height. For a 12-inch bed: 200 sq ft × 12 ÷ 324 = 7.41 yd³ raw, plus 18% settling = 8.74 yd³. Split that 70% topsoil / 30% compost for most vegetables: 6.12 yd³ topsoil and 2.62 yd³ compost. Root crops like carrots want 10–15 inches; leafy greens do fine at 8.
What is the best topsoil mix for vegetables?
The most common extension-service recommendation is 70% topsoil and 30% compost by volume. Some growers use 50/50 for heavier soils or 60/30/10 with sand for drainage. Pure compost is too rich and holds too much water; pure topsoil is too lean. Blend before filling. Never use fill dirt for a vegetable bed.
How do I measure an irregular or curved garden bed?
Break the bed into the largest rectangles you can fit inside it, then add circles or half-circles for the curved ends and triangles for angled wedges. For very irregular shapes, use the offset method: lay a tape along one edge, measure the width at regular intervals, average the widths, and multiply by the interval length. Add 5% to the total for safety.
Do I need to remove old topsoil before adding new?
Usually no. If the existing topsoil is at least 3–4 inches and drains well, till it and blend the new layer into it. Remove only if it is compacted, contaminated, or sits on a hardpan layer that blocks roots. Removing and replacing is expensive — a test hole tells you whether it is necessary.
How do I check the quality of topsoil before buying?
Three quick tests: Squeeze test — moist soil should crumble loosely; clay ribbons, sand falls apart. Smell test — good topsoil smells earthy, not sour or chemical. Jar test — fill a jar one-third with soil, top with water, shake, and let settle. Sand settles first, then silt, then clay. The proportions tell you the texture. Ask the supplier for a recent pH and organic matter test.
What is the difference between topsoil, fill dirt and compost?
Topsoil is the upper layer of native soil, screened and used for growing. Fill dirt is subsoil or lower-grade material used for bulk grading and elevation; it has little organic matter. Compost is decomposed organic matter used to amend soil fertility and structure. Most beds need a blend of topsoil and compost; fill dirt is for the base layer below them.
How much does topsoil cost?
Bulk screened topsoil runs $25 to $50 per cubic yard delivered in most markets. Unscreened fill dirt is $10 to $25. Premium blends with compost run $40–$70. Bagged topsoil at retail is $3–$7 per 40 lb bag, which works out to $90–$200 per cubic yard equivalent. Delivery adds $50–$150 per load with a 2–5 yard minimum from most yards.
How much area does a cubic yard of topsoil cover?
One cubic yard covers: 324 sq ft at 1 inch, 162 sq ft at 2 inches, 108 sq ft at 3 inches, 81 sq ft at 4 inches, 54 sq ft at 6 inches, or 27 sq ft at 12 inches. Divide 324 by the depth in inches to get the coverage at any depth.
Should I add sand to topsoil for drainage?
Only if the topsoil is heavy clay. Adding sand to clay creates a concrete-like mix — the opposite of what you want. For clay soil, add compost instead. For sandy soil that drains too fast, add compost to hold moisture. Sand is useful in raised bed blends at 10% by volume for aeration, not as a general drainage fix.
How long does topsoil take to settle?
Most settling happens in the first 4 to 8 weeks after spreading and watering. Light watering accelerates it. Do not compact fresh topsoil with machinery — that destroys the structure. After two months, walk on it, water it, and top up any low spots with the leftover 15% buffer you ordered. Plant after the first major settling is done.
Is this calculator free and does it store my data?
Yes and no. Every calculation runs entirely in your browser — nothing is sent to a server, nothing is stored. Your inputs are not saved anywhere. The only thing remembered is the rating counter, which uses your browser's local storage and never leaves your device.
Related Calculators
References
- ASTM D5268 — Standard Specification for Topsoil Used for Landscaping Purposes. ASTM International.
- ASTM D7263 — Standard Test Methods for Laboratory Determination of Density (Unit Weight) of Soil Specimens. ASTM International.
- ASTM D4972 — Standard Test Methods for pH of Soils. ASTM International.
- ASTM D2974 — Standard Test Methods for Moisture, Ash, and Organic Matter of Peat and Other Organic Soils. ASTM International.
- AASHTO T180 — Standard Method of Test for Moisture-Density Relations of Soils Using a 4.54-kg Rammer and a 457-mm Drop.
- British Standards Institution. BS 3882: Specification for Topsoil.
- USDA Natural Resources Conservation Service. Soil Quality Indicators.
Confirm topsoil quality, pH and organic matter with a soil test before purchase. Topsoil quantities from this calculator are planning estimates. Depth and settling characteristics vary by soil type and local conditions.