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Mill and Fill Calculator — RAP Tonnage and New Mat Tons

A mill-and-fill takeoff asks two different questions about the same rectangle: how much pavement comes off, and how much goes back on. Enter the area, the mill depth and the new lift thickness, and this tool returns both tonnage figures from one pass — milled RAP by its own stockpile unit weight, new hot mix by mix density — plus the haul and delivery loads and a profile check that tells you whether the finished surface ends up above or below the existing grade.

The Formula

RAP tons = (Area sq ft × Mill depth in ÷ 12) × RAP unit weight lb/ft³ ÷ 2,000 • New mat tons = (Area × Lift thickness ÷ 12) × HMA density ÷ 2,000 × (1 + Allowance %) • Surface change = Lift thickness − Mill depth

How the Calculation Runs

  1. Convert the mill depth to feet and multiply by area for milled cubic feet; divide by 27 for cubic yards.
  2. Multiply milled volume by the milled RAP unit weight, then by 1 ÷ 2,000 for haul-away tons.
  3. Convert the new lift thickness to feet, multiply by area and by hot-mix density for net mat tons.
  4. Apply the order allowance to the new mat only — a cut that comes off the road never needs an overage.
  5. Divide each tonnage by truck capacity and round up separately, because hauling off and delivering are different trips on different tickets.
  6. Subtract mill depth from lift thickness for the profile check, the number that decides whether curbs and garage sills still line up.

What Each Variable Means

SymbolVariableUnitNotes
AMilled areasq ftOne number drives both sides. Split irregular lots with the multi-area calculator first.
DmMill depthinCut taken by the machine, measured from the existing surface.
γrMilled RAP unit weightlb/ft³Stockpiled, not rolled. See the asphalt density guide for every material band.
TfNew lift thicknessinCompacted thickness of the replacement course — the same convention the square feet to tons calculator uses.
ΔSurface changeinTf − Dm. Zero means the pavement comes back at the same elevation.

Entering Your Numbers

  • Area to mill (sq ft)
  • Milling depth (in) — How deep the drum cuts. Mill below the depth of distress — that is what makes an overlay hold.
  • Milled RAP unit weight (lb/ft³) — FHWA-RD-97-148: milled or processed RAP runs 120–140 lb/ft³ in the stockpile. This is not the compacted-RAP figure.
  • New lift thickness (in) — Compacted thickness of the HMA you put back. Set it equal to the mill depth to hold grade.
  • Density (lb/ft³) — Typical hot mix runs 142–148 lb/ft³. Use your supplier’s mix-design value when you have it.
  • Order allowance — Covers edges, cuts, and measurement error. Not a compaction factor.
  • Truck capacity (tons) — Applied to haul-away and delivery. Leave blank to skip loads.
  • Your price per ton ($) — Optional — material-only, as quoted by your plant.

Known Limitations

  • The profile check compares two thicknesses only. It does not know your curb heights, garage lip, drainage swales or utility setbacks — check those before you commit to a cut deeper than the lift you can fit.
  • Milling produces a loose, aerated material. The FHWA band used here (120–140 lb/ft³) is for milled or processed RAP in a stockpile; if your hauler weighs loads, reconcile against tickets rather than this figure, and read the compacted vs loose asphalt guide before adjusting it.
  • No milling, haul or disposal price is built in. Equipment time, truck distance and dump fees are project-specific, so any dollar figure here comes only from the optional price you enter.
  • Structural decisions — how deep to cut, whether the base needs work, whether a level-up course is required — belong to the overlay guide and your paving engineer. This tool converts a decision into quantities.

Worked Examples

Every number below is produced by the same engine at build time — not typed by hand.

Same-depth mill and fill — 1,000 sq ft, 2 in off, 2 in back

New asphalt to order: 12.69 US tons

  1. Area: 1,000 sq ft milled and paved = 111.11 sq yd
  2. Milled depth: 2 in ÷ 12 = 0.1667 ft
  3. Milled volume: 1,000 sq ft × 0.1667 ft = 166.67 ft³ (6.17 yd³)
  4. RAP to haul away: 166.67 ft³ × 130 lb/ft³ ÷ 2,000 = 10.83 US tons
  5. Haul loads out: 10.83 tons ÷ 20-ton truck (round up) = 1 load, last 10.83 tons
  6. New mat tons: 1,000 sq ft × 0.1667 ft × 145 lb/ft³ ÷ 2,000 = 12.08 US tons
  7. New mat order: 12.08 tons × (1 + 0.05) = 12.69 tons
  8. Delivery loads in: 12.69 tons ÷ 20-ton truck (round up) = 1 load, last 12.69 tons
  9. Surface change: 2 in new lift − 2 in milled = +0 in (0 mm) at the existing grade
  10. Total truckloads: 1 out + 1 in = 2 moves

Rut correction — 2,400 sq ft, 3 in off, 2 in back

New asphalt to order: 30.45 US tons

  1. Area: 2,400 sq ft milled and paved = 266.67 sq yd
  2. Milled depth: 3 in ÷ 12 = 0.25 ft
  3. Milled volume: 2,400 sq ft × 0.25 ft = 600 ft³ (22.22 yd³)
  4. RAP to haul away: 600 ft³ × 130 lb/ft³ ÷ 2,000 = 39 US tons
  5. Haul loads out: 39 tons ÷ 25-ton truck (round up) = 2 loads, last 14 tons
  6. New mat tons: 2,400 sq ft × 0.1667 ft × 145 lb/ft³ ÷ 2,000 = 29 US tons
  7. New mat order: 29 tons × (1 + 0.05) = 30.45 tons
  8. Delivery loads in: 30.45 tons ÷ 25-ton truck (round up) = 2 loads, last 5.45 tons
  9. Surface change: 2 in new lift − 3 in milled = −1 in (25.4 mm) below the existing grade
  10. Total truckloads: 2 out + 2 in = 4 moves

Frequently Asked Questions

What is mill and fill?

Milling shaves a measured depth off the existing pavement; filling puts new hot mix back to bring the surface to grade. It repairs rutting and cross slope without raising the road, so curbs, gutters and driveways stay where they are. This calculator sizes both sides of that exchange from the same area.

How many tons of millings do I get per inch of milling?

That depends entirely on the unit weight of the material coming off, so the calculator runs it rather than quoting a rule of thumb. Enter the area and depth and read the haul-away tonnage; the default sits on the FHWA-RD-97-148 band for milled or processed RAP, 120–140 lb/ft³, which covers most dense-graded surface courses. Moisture and aggregate type move individual loads more than they move the takeoff.

Should the mill depth equal the new lift thickness?

If you want the surface back at the same elevation, yes — mill and fill the same number. Cut deeper than you fill and the pavement ends up low (water holds, trip risk at the apron); fill thicker than you mill and it ends up high, which is how overlays choke a garage door.

Is the order allowance applied to milled tonnage too?

No, and that is deliberate. An allowance covers short-order risk on material you buy. Milled pavement is a measured cut — it is already there — so it is reported net, with no overage stacked on it.

Can I reuse the millings?

Sometimes, as a base or driveway surface, but that is a material decision, not a conversion: reclaimed asphalt is a separate page in this series.

Sources & Data Lineage

  • FHWA-RD-97-148, Reclaimed Asphalt Pavement — Material Description: milled or processed RAP unit weight 1940–2300 kg/m³ (120–140 lb/ft³). Reviewed 2026-10. www.fhwa.dot.gov
  • Asphalt Paving Handbook (NAPA/AAPTP), §5.3 Surface Preparation for Overlays — mill to below the depth of distress; level-up course practice. Reviewed 2026-09. handbook.asphaltpavement.org
  • FHWA TechBrief FHWA-HIF-19-053, Thin Asphalt Overlays — rut depth limits that trigger milling. Reviewed 2026-09. www.fhwa.dot.gov
  • FHWA Western Federal Lands Estimating Handbook — hot-mix asphalt density basis for the 145 lb/ft³ planning default. Reviewed 2026-09.

Related Calculators

When to mill and fill instead of overlayingOrder tonnage for a single new liftSplit loads for delivery and haul-awayUnit weights for HMA, RAP and base