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AutoCAD Scale Converter

Compute the object scale factor between any two drawing scales for any paper size. Supports ISO A-series, ANSI/Arch, all imperial fractions, and all common metric ratios. Source-derived from EEP_v6_3_2.lsp standard scale tables.

✓ ISO 5455 · ANSI Y14.5 ✓ Metric & Imperial ✓ Annotative scale ready

Inputs

Pick paper size, source scale, target scale. Result = source / target (object scaled to print correctly when plotted at target scale).
How to apply in AutoCAD: Use the SCALE command with the resulting factor on the selected objects, or set the DIMSCALE / LTSCALE / VPSCALE system variables. For annotative objects, add the target scale via OBJECTSCALE instead — equivalent to c:ASC in EEP_v6_3_2.lsp.

Result

Click Compute. Result includes scale factor, text-height recommendation, and trace.
Set inputs and press Compute scale factor.
Output: factor, scaled object size, recommended text height (per paper-space ≈ 2.5 mm rule), and step-by-step trace.

Standard text-height reference

Company drawing-scale-based text heights — extracted verbatim from EEP_v6_3_2.lsp · *EEP-LT-TEXT-SIZE-DB* (lines 2225–2273).
ScaleGeneralMediumLargeUse
Metric 1:2560 mm90 mm135 mmEquipment elevations, large details
Metric 1:50120 mm180 mm270 mmPlans, sections, room-level details
Metric 1:75180 mm270 mm405 mmMedium plans
Metric 1:100240 mm360 mm540 mmFloor plans (most common)
Metric 1:125300 mm450 mm675 mmSite / context plans
Metric 1:150360 mm540 mm810 mmSite plans
Metric 1:200480 mm720 mm1080 mmMaster / overall plans
Imperial 1/2"=1'-0"2.25 in (57 mm)3.75 in (95 mm)6.00 in (152 mm)Large-scale details
Imperial 1/4"=1'-0"4.50 in (114 mm)7.50 in (191 mm)12.0 in (305 mm)Floor plans (most common imperial)
Imperial 1/8"=1'-0"9.00 in (229 mm)15.0 in (381 mm)24.0 in (610 mm)Small-scale plans
Imperial 1/16"=1'-0"18.0 in (457 mm)30.0 in (762 mm)48.0 in (1219 mm)Site plans
Paper Space2.4 mm (3/32 in)3.6 mm (1/8 in)5.4 mm (1/4 in)Printed nominal