Postcard Size Rule Checker
Validates postcard dimensions against standard mail minimums and maximums.
How to use
- 1Open the Postcard Size Rule Checker tool page.
- 2Enter or paste your input into the provided fields.
- 3The tool processes your input instantly in your browser.
- 4Copy or download the result using the buttons provided.
Privacy & limitations
- Processing happens locally in your browser — nothing is uploaded.
- Works on modern desktop and mobile browsers.
- Very large inputs may take a moment; the interface will show progress.
Related tools
Spine Width Calculator
Calculates finished book spine thickness in mm or inches from page count, paper caliper, and cover board weight.
Book Block Thickness Estimator
Predicts total book block depth from sheet count, paper bulk factor, and swell allowance.
Paperback Spine Text Width Planner
Computes the maximum readable spine text width from final spine thickness.
Hardcover Case Board Calculator
Works out case board dimensions from trim size, overhang, and hinge allowances.
Case Wrap Cloth Yield Calculator
Estimates cloth or paper wrap area needed for a given case size and turn-in width.
Dust Jacket Flap Width Calculator
Computes flap width and fold positions from trim size and jacket coverage goals.
Dust Jacket Spine Score Planner
Places spine score lines and fold marks from trim, bleed, and board thickness inputs.
Endpaper Size Calculator
Calculates endpaper sheet size from trim size, trimming allowance, and guard margin.