THE NUMBERS, EXPLAINED
How to use this calculator.
Calculates ideal straight-edge cut dimensions from concentric diameters. Inside-following reduces dimensions; outside-following increases them. Corner radii, bushing clearance, runout, depth and tool compatibility need separate checks.
Start with your inputs
Enter guide bushing outside diameter (mm), cutter diameter (mm), rectangular template width (mm), rectangular template height (mm), follow inside opening (1) or outside template (2). Keep amounts in the units shown on each field. The example is a starting point, not a recommended value.
| Input | Example value |
|---|---|
| Guide bushing outside diameter (mm) | 20 |
| Cutter diameter (mm) | 10 |
| Rectangular template width (mm) | 200 |
| Rectangular template height (mm) | 100 |
| Follow inside opening (1) or outside template (2) | 1 |
A worked example
With the example inputs above, offset per edge (mm) is 5. Change the inputs to explore your own scenario.
| Result | Example answer |
|---|---|
| Offset per edge (mm) | 5 |
| Resulting cut width (mm) | 190 |
| Resulting cut height (mm) | 90 |
How this is calculated
Offset per edge (mm)
Half the difference between bushing and cutter diameters.
Resulting cut width (mm)
Template width minus twice the offset for inside, plus twice for outside.
Resulting cut height (mm)
Template height minus twice the offset for inside, plus twice for outside.
Symbols and units
- a
- Guide bushing outside diameter (mm)
- b
- Cutter diameter (mm)
- c
- Rectangular template width (mm)
- d
- Rectangular template height (mm)
- e
- Follow inside opening (1) or outside template (2)
Use the units shown. A list keeps the order in which you enter its values. The symbol ^ means “raised to the power of”.
Assumptions and limits
Calculates ideal straight-edge cut dimensions from concentric diameters. Inside-following reduces dimensions; outside-following increases them. Corner radii, bushing clearance, runout, depth and tool compatibility need separate checks.
Calculations use the values you enter. Blank or invalid inputs show an error instead of silently substituting zero. Results are displayed to useful precision; calculations retain the underlying numeric precision.
Questions about this tool
What does the result tell me?
Offset per edge (mm); Resulting cut width (mm); Resulting cut height (mm). The result applies to the method and inputs described above. Check the units and assumptions before using it in a decision.
Why might another calculator differ?
Differences in units, rounding, timing or model definitions can produce different answers. Compare the input definitions and the method, rather than only the final number. For this tool: Calculates ideal straight-edge cut dimensions from concentric diameters. Inside-following reduces dimensions; outside-following increases them. Corner radii, bushing clearance, runout, depth and tool compatibility need separate checks.
Are my inputs stored or sent to AI?
Calculations on this page happen in your browser. The separate AI question finder sends its submitted conversation to OpenAI; these calculator fields are not sent. Favourites and recent tool names are stored locally. A shared link contains the inputs you choose to include.
Further reading
OpenStax: geometric formulas and arithmetic ↗
Background reading; this does not imply endorsement or independent review of SumFizz.
Review status
Software example and browser checks are recorded in our quality report. No external expert review is claimed. Created with coding assistance; calculations run as ordinary browser code.
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