2400 mm and 8 ft timber: the 38.4 mm difference

Published by DraftVano, the tool's publisher. AI-assisted explanation checked against our calculator model. This is a planning example, not a completed customer build.

A timber label that says “2400mm / 8ft” can look like a direct conversion. It is not. If your cut list nearly fills a board, the difference can change how many boards you need.

The difference is 38.4mm

One inch is 25.4mm. Eight feet is 96 inches, so an exact 8ft length is 96 × 25.4 = 2438.4mm. A 2400mm board is approximately 94.488 inches. The two stock lengths differ by 38.4mm (about 1.512 inches).

Neither label tells you that the actual board has square, undamaged ends or exactly that usable length. Measure the stock and choose an end allowance for the material you really have.

A cut list where that difference matters

Suppose you need two finished pieces, each 1200mm long, and the cut between them removes 3mm. With zero end allowance, the two finished lengths plus their separating cut need 1200 + 3 + 1200 = 2403mm.

• 2400mm stock: one board is too short. The calculator suggests two boards.
• Exact 8ft / 2438.4mm stock: one board has room for the two parts. In our calculator, the remaining tail also receives a final 3mm separating cut, leaving a calculated 32.4mm offcut when end allowance is zero.

Zero allowance is appropriate only when the stock ends already suit the job. With a 5mm reserve at each end, the 8ft board still fits this example, while the calculated offcut falls to 22.4mm. Actual cutting methods and usable stock still need checking.

Keep the calculation in one system

1. Write down finished part lengths and quantities. These are the lengths your design needs, not a guess at how much stock to buy.
2. Measure the actual stock length. Enter 2400mm for 2400mm stock. Enter 96 inches for an exact 8ft board. Do not replace one with the other simply because a catalogue groups them together.
3. Add the actual blade kerf and end reserves. The 3mm kerf here is an example, not a universal blade specification. The end reserve applies at each end.
4. Review the board map before cutting. Check defects, grain, safe workholding and every finished measurement. A layout cannot check the suitability of your design.

Open this exact 8ft-stock example in the free calculator →

The free browser tool accepts mm or decimal inches and produces a suggested board map, CSV, printable output and a share link. No account or plan purchase is needed. It handles straight timber lengths for one section and stock length per run. Its first-fit-decreasing arrangement is a suggestion, not a guaranteed minimum or a plywood-sheet layout.

Exact room dimensions are a separate decision

A 2183mm space should not silently become 2180mm when you enter it into a configurator. DraftVano's six project builders preserve exact dimension inputs and have 1mm metric adjustments. Physical fit still needs deliberate installation clearances, connection details and checks against the real room or appliance.

If you already have your part lengths, use the free calculator. If you need a generated timber-framing design too, browse the six project families and inspect the fixed PDF samples first. Configured project PDFs are separate purchases from EUR 9.90, with optional M-04 guidance EUR 4.90 extra (EUR 14.80 total). They do not provide structural certification or CNC/DXF files.

For the different case where one finished part already fills a suitable board exactly, read the worked kerf and exact-fit guide. A part that needs no shortening cut does not automatically require another blade width.