MOACUTSheet planning guide
How to Calculate Required Sheet Quantity
A sheet-area division gives a useful lower bound, but it does not prove that every rectangular part will physically fit. This guide shows how part dimensions, quantity, kerf, edge margin, and rotation turn an area estimate into a usable nesting result.
Last updated: August 31, 2026What required sheet quantity means
Required sheet quantity is the number of stock sheets allocated by a valid layout for the complete cut list. A cut list is not complete unless every part size is paired with its required quantity. Ten parts at 600 × 400 mm require ten separate rectangles in the layout, even when they share one line in the input table.
MOACUT expands each quantity into individual rectangular parts, sorts the parts from larger area to smaller area, and tries candidate positions from the bottom-left of sheets already opened. When a part cannot be placed on an existing sheet, the calculation opens another sheet. The displayed Required Sheets value is the resulting number of allocated sheets.
Start with the area lower bound—not the final order quantity
Area lower bound = ceiling(part area total ÷ one sheet area)
This calculation answers a narrow question: how many sheets would be needed if the part area could fill sheets without geometric constraints. It ignores whether widths can share a row, whether heights fit the remaining strip, and whether space must be reserved between parts or around the edge.
Use the area lower bound as a quick reasonableness check. Then run a nesting calculation to determine whether real rectangles fit. A result can legitimately use more sheets than the lower bound because an unused strip may have enough area but the wrong shape.
Inputs that can change the required sheet count
| Input | How MOACUT uses it | Planning consequence |
|---|---|---|
| Sheet width and height | Define the full stock rectangle. | Changing either dimension changes which rows and columns can fit. |
| Part width, height, quantity | Create the rectangles that must all be placed. | Two lists with equal total area can require different layouts. |
| Kerf | Acts as the required spacing between neighboring rectangles. | Spacing can prevent a row from fitting even when its part widths alone fit. |
| Edge margin | Reduces usable width and height by twice the entered margin. | A 10 mm margin reserves 10 mm on all four sides. |
| Allow rotation | Lets a non-square rectangle swap width and height by 90° during placement. | Rotation may fill a narrow remainder; turn it off for directional material. |
MOACUT workflow: input, calculate, inspect
- Enter the actual stock sheet width and height in millimetres, or select a preset and verify it against the material being purchased.
- Enter every rectangular part's finished width, height, and quantity. CSV import accepts rows in Width, Height, Quantity order.
- Set the inter-part kerf/spacing and the four-sided sheet edge margin for the planned process.
- Enable rotation only when turning a part by 90° is acceptable for grain, print direction, or surface finish.
- Sign in and run the nesting calculation. Inspect each sheet drawing, not only the summary cards.
- Read Required Sheets, Used Area, Material Utilization, Scrap, and Estimated Material Cost together.
MOACUT multiplies the calculated sheet count by the user-entered cost per sheet. It does not add machine time, labour, tooling, tax, delivery, or finishing costs.
Worked example: why one sheet by area can become two
The following scenario was evaluated with MOACUT's current quantity expansion, largest-area-first ordering, bottom-left candidate search, margin handling, rotation checks, and overlap rules.
The twelve parts have a pure area of 12 × 600 × 400 = 2,880,000 mm² (2.88 m²). The full sheet area is 1220 × 2440 = 2,976,800 mm². Area division therefore gives a lower bound of one sheet.
| Scenario | MOACUT result | Parts per sheet | Overall utilization | Overall scrap |
|---|---|---|---|---|
| Kerf 0 mm | 1 required sheet | 12 | 96.7% | 3.3% |
| Kerf 3 mm | 2 required sheets | 10 + 2 | 48.4% | 51.6% |
With the 10 mm margin, usable width is 1200 mm. At zero spacing, two 600 mm parts fit exactly across. At 3 mm spacing, that same pair needs 1203 mm, so the simple two-column layout no longer fits. The calculation places ten parts on the first sheet and two on the second.
The utilization drop does not mean kerf consumes 51.6% of the material. The second sheet is only partly occupied, and MOACUT reports pure part area divided by the full area of all allocated sheets. The example demonstrates why the final layout—not area alone—determines the purchasing quantity.
How to read the result cards
- Required Sheets: number of sheet arrays created by the placement calculation.
- Used Area: sum of placed rectangle width × height, converted to square metres for display.
- Material Utilization: pure placed part area divided by full nominal area of all required sheets.
- Scrap: 100% minus overall material utilization. It includes all unoccupied area, including margin, spacing, and unusable remnants.
- Estimated Material Cost: required sheets × entered unit cost.
Each individual sheet drawing also shows its own utilization and scrap. This makes a lightly occupied final sheet visible even when the overall percentage looks acceptable.
Practical considerations and limits
MOACUT currently nests rectangular parts with optional 90° rotation using a bottom-left placement procedure. It is a practical estimate and layout, not a mathematical guarantee that no alternative arrangement could use fewer sheets. Re-run the plan when a sheet size, part quantity, spacing, margin, or rotation rule changes.
Do not use a layout as the sole instruction for physical cutting. Confirm actual stock dimensions, damaged edges, grain or print direction, machine holding areas, tool behaviour, tolerances, and process safety before ordering or machining.