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SnapScaleCalc

Help & resources

Help & Resources

Need help with a calculation? Most questions can be answered directly from the calculators, methodology and reference pages below. If something still looks wrong, you can contact SnapScaleCalc by email at the bottom of this page.
  • Find the right tool
  • Understand a result
  • Report a problem

Find the right tool

Grouped by the job you are doing rather than by keyword.

Resize something

Change one dimension into another and read the factor, percentage, area and volume effects together.

Convert between scales

Move between representative scales such as 1:72 and 1:48 and get the exact resize percentage.

Model making

Work between real and model dimensions, and compare the result against documented scale conventions.

Make something fit

Find the largest uniform scale that still fits inside a defined space, with the limiting axis named.

3D printing

Slicer percentage, resulting XYZ dimensions, geometric volume change and build-volume fit.

Drawings and architecture

Drawing-to-real dimensions, representative scales and imperial architectural notation.

Maps

Map distance, ground distance and the representative fraction between them.

Multiple resizes

Combine sequential resize operations into one factor, with the reciprocal correction back.

Fix a printed scale

Compare expected against measured output and separate uniform from non-uniform distortion.

Understand your result

You have a number and want to know what it means, or why it differs from what you expected.

Reference and scale conventions

Calculated value vs documented convention

  • A mathematical scale and a documented convention are two different things. The first is arithmetic; the second is what a field has settled on using.
  • SnapScaleCalc calculates the mathematical result first, and never bends it to fit a convention.
  • Documented conventions are shown separately, alongside the calculated value, where they are relevant.
  • Conventions can differ by field, organisation, era and region, so a nearby convention is a comparison, not a correction.
→ Common scales reference

Documented conventions by field, each with the source it was taken from.

→ Methodology

Definitions, formulas and how reference data is sourced and presented.

Accuracy and limitations

Exact arithmetic

The engine can calculate the relationship you enter exactly, and derives area and volume effects from the unrounded factor rather than from a displayed value.

Real-world accuracy

A result is only as meaningful as the measurements and assumptions behind it. A mis-measured edge or the wrong unit produces an exact answer to the wrong question.

Specialised limits

3D printing, drawings, manufacturing, maps, fit-to-space and print correction all carry real-world limits beyond pure geometry — tolerances, material behaviour, projection and device output.

→ How the calculations work→ Disclaimer and scope of use

Something looks wrong?

Nine checks that explain most unexpected results. Work through them before writing.
  • The input values themselves — a transposed digit is the most common cause.
  • The selected units on every field, including mixed metric and imperial input.
  • Whether your percentage means scale to that value or increase by it.
  • The direction: original → target, not target → original.
  • The representative-scale direction — 1:48 is larger than 1:72, not smaller.
  • Whether the drawing or print you measured had already been resized once.
  • Whether displayed rounding is being read as the internal value.
  • Whether X and Y print distortion actually differ, which no single factor can fix.
  • Whether the fit assumptions — clearance, rotation, bounding box — match your real problem.

Report a calculation issue

Include this

  • The page or calculator you used
  • The exact values you entered
  • The units selected for each value
  • The result shown
  • The result you expected
  • The steps needed to reproduce it
  • Your browser and device, if the problem looks like an interface issue

Reference or source corrections

  • The scale or convention entry concerned
  • What appears to be incorrect
  • The issuing organisation or source
  • A direct source URL where one exists
  • Publication, version or date where known

Verifiable primary sources are preferred: a standard, a specification, or the body that defines the convention.

Calculation reports come first

A reproducible arithmetic error is treated as the most serious kind of report here, ahead of any other change to the site.

Privacy, terms and scope

→ Privacy policyWhat is and is not processed when you use the calculators.→ Terms of useThe terms covering use of the site and reuse of its material.→ DisclaimerWhere calculated results stop and real-world responsibility begins.→ About SnapScaleCalcWhat this site is, how it is built and what it deliberately leaves out.

Still need help?

Email is the way to reach SnapScaleCalc. There is no contact form, no account and no newsletter. Write about:

  • Calculation problems and bug reports
  • Source or reference corrections
  • Accessibility or usability problems
  • Privacy, terms or legal questions
  • General site feedback
  • Requests for a calculator that is missing

Email

snapscalecalc@proton.me

Replies are written by a person, so no response time is promised. Your message and email address are handled by the mailbox provider and kept only as long as needed to deal with the issue.