Toolarithm

Unit Converter

Paper Size Converter

Physical dimensions. Clear raster choices.

Plan your sheet

Physical size. Explicit pixel policy.

Bleed and safe area
Raster planning

Whole PPI from one through 2400; independent of CSS reference pixels.

View paper results
Precision and report
Worked presets

ISO A4 finished trim dimensions

210.0000000×297.0000000 mm210.0000000\times297.0000000\,\mathrm{mm}

Nominal physical dimensions in the selected orientation. Display rounding does not change the exact calculation. Printer scaling and nonprintable margins are not inferred.

Raster planning for the trim sheet

Nx×Ny=2480×3508 pxN_x\times N_y=2480\times3508\,\mathrm{px}

Requested density: 300 pixels per inch. Rounding: nearest. Axes are rounded independently.

Ntotal=8699840 pxN_{\mathrm{total}}=8699840\,\mathrm{px}

Effective horizontal density

Px≈299.9619048 px/inP_x\approx299.9619048\,\mathrm{px/in}

Effective vertical density

Py≈300.0107744 px/inP_y\approx300.0107744\,\mathrm{px/in}

Whole-pixel rounding can slightly change effective density on each axis. Raster PPI is independent of printer dot resolution and CSS reference pixels.

Relative paper rectangles
Outline: finished trim sheet. This is a proportion diagram, not an actual-size measuring template.

Trim area

A=0.06237000000 m2A=0.06237000000\,\mathrm{m^2}

Width-to-height ratio

WtHt≈0.7070707071\frac{W_t}{H_t}\approx0.7070707071

Finished trim dimensions by unit

Unit conventionWidthHeight
MillimetersW=210.0000000 mmW=210.0000000\,\mathrm{mm}H=297.0000000 mmH=297.0000000\,\mathrm{mm}
CentimetersW=21.00000000 cmW=21.00000000\,\mathrm{cm}H=29.70000000 cmH=29.70000000\,\mathrm{cm}
International inchesW≈8.267716535 inW\approx8.267716535\,\mathrm{in}H≈11.69291339 inH\approx11.69291339\,\mathrm{in}
PostScript pointsW≈595.2755906 ptW\approx595.2755906\,\mathrm{pt}H≈841.8897638 ptH\approx841.8897638\,\mathrm{pt}
PostScript picasW≈49.60629921 pcW\approx49.60629921\,\mathrm{pc}H≈70.15748031 pcH\approx70.15748031\,\mathrm{pc}
CSS reference pixelsW≈793.7007874 pxCSSW\approx793.7007874\,\mathrm{px}_{\mathrm{CSS}}H≈1122.519685 pxCSSH\approx1122.519685\,\mathrm{px}_{\mathrm{CSS}}

Step-by-step paper size calculation

  1. 1. Resolve the oriented trim sheet

    Use nominal catalog dimensions or convert the literal custom dimensions to millimeters, then apply the chosen orientation. Ledger keeps its defined landscape order in native mode.

    Wt×Ht=210.0000000×297.0000000 mmW_t\times H_t=210.0000000\times297.0000000\,\mathrm{mm}

  2. 2. Apply bleed and safe margins to the oriented sheet

    Bleed extends outward; safe margins inset the trim. The top, right, bottom and left edges belong to the final orientation. No printer nonprintable area is inferred.

    Wb=Wt+bL+bR,Hb=Ht+bT+bB,Ws=Wt−mL−mR,Hs=Ht−mT−mBW_b=W_t+b_L+b_R,\quad H_b=H_t+b_T+b_B,\quad W_s=W_t-m_L-m_R,\quad H_s=H_t-m_T-m_B

  3. 3. Convert the selected raster box to pixel axes

    Raster pixels use the selected pixels per inch and explicit integer rounding. CSS reference pixels use a fixed definition and are a separate table row.

    px=Wmm25.4P,py=Hmm25.4P,Nx×Ny=2480×3508 pxp_x=\frac{W_{\mathrm{mm}}}{25.4}P,\quad p_y=\frac{H_{\mathrm{mm}}}{25.4}P,\qquad N_x\times N_y=2480\times3508\,\mathrm{px}
What Can You Create?

Create a precise sheet and artwork specification

Named or custom trim dimensions

Choose among thirty-three nominal sheets, preserving all fourteen original identifiers. ISO A, ISO B, North American and ANSI choices are labeled explicitly; custom dimensions cover other physical rectangles without guessing a paper standard.

A clearly oriented layout

Keep defined order or apply portrait or landscape, then state bleed and safe margins on the final edges. Linked controls handle uniform amounts; independent controls allow different top, right, bottom and left values.

A reproducible raster estimate

Choose pixels per inch and integer rounding rather than treating a floating-point pixel estimate as a file dimension. The trim or bleed rectangle supplies the physical extent, and effective density is reported separately on each axis.

Paper size formulas and worked examples

Use the exact international inch relationship

Physical units share a defined length relationship. PostScript points and picas, along with CSS reference pixels, use the inch factors below. The table applies these factors to the oriented trim dimensions. Raster pixels are calculated separately, because their count depends on a chosen sampling density rather than only on a fixed unit definition.

1 in=25.4 mm=72 pt=6 pc=96 pxCSS1\,\mathrm{in}=25.4\,\mathrm{mm}=72\,\mathrm{pt}=6\,\mathrm{pc}=96\,\mathrm{px}_{\mathrm{CSS}}

Example: A4 at a stated sampling density

For nominal A4 dimensions and 300 px/in300\,\mathrm{px/in}, divide each millimeter axis by the exact millimeters-per-inch factor, then multiply by the requested density. Nearest-integer rounding produces the familiar pair below. Other rounding policies can change an axis, so the requested density and policy belong with the saved dimensions.

px=21025.4⋅300,py=29725.4⋅300,(Nx,Ny)=(2480,3508)p_x=\frac{210}{25.4}\cdot300,\quad p_y=\frac{297}{25.4}\cdot300,\qquad (N_x,N_y)=(2480,3508)

Example: outward bleed and inset safe area

With A4 trim, a uniform 3 mm3\,\mathrm{mm} bleed extends each side outward. A uniform 5 mm5\,\mathrm{mm} safe margin moves each side inward. Their effects are opposite, and each dimension includes two edges. Independently entered edges use the same rule, with the corresponding left/right or top/bottom values applied after orientation.

(Wb,Hb)=(216,303) mm,(Ws,Hs)=(200,287) mm(W_b,H_b)=(216,303)\,\mathrm{mm},\qquad (W_s,H_s)=(200,287)\,\mathrm{mm}

Check effective density after integer rounding

The actual integer pixel axes may imply slightly different horizontal and vertical sampling densities. Divide each rounded axis by its physical extent in inches to check those values. The physical trim area and aspect ratio are separate geometric quantities; neither a larger pixel count nor more displayed significant figures changes the nominal sheet dimensions.

Px=NxWin,Py=NyHin,A=WtHtP_x=\frac{N_x}{W_{\mathrm{in}}},\quad P_y=\frac{N_y}{H_{\mathrm{in}}},\qquad A=W_tH_t
Why Users Love This Tool

Keep physical dimensions and raster choices understandable

Exact arithmetic before presentation

  • Nominal catalog decimals and literal custom dimensions retain exact rational values. Rounded displays never feed later box or pixel calculations.
  • Safe-area validation checks the final oriented trim sheet. Invalid edges clear stale output instead of silently clamping the inner rectangle.
  • Area and width-to-height ratio derive from nominal dimensions. An ISO series label does not replace the listed millimeter dimensions with an ideal irrational ratio.

Complete records for later checking

  • Copied text and CSV include all unit rows, chosen edge values, raster rounding and exact numerator/denominator certificates, even if visible sections are hidden.
  • Sharing retains active custom dimensions and layout choices after validation. Dormant custom buffers and hidden linked-edge values do not leak into the shared model.
  • Server-rendered A4 results and accessible mathematical markup remain available before interactive code loads. Invalid edits and clipboard limitations receive clear feedback.
Perfect For

Useful for page setup, artwork planning and teaching

Document and drawing preparation

Compare a named sheet with the physical dimensions expected by a layout application. Ledger ordering, portrait/landscape and explicitly labeled ISO B sizes help avoid ambiguous page-setup choices.

Image export planning

Inspect a trim or full-bleed raster estimate at a stated sampling density. Compare the exact continuous pixel request with the chosen whole axes and their resulting effective densities.

Measurement and unit exercises

Follow the exact inch relationship through millimeters, points, picas and CSS reference pixels. The proportion diagram helps explain trim, outward bleed and inset safe area without implying that the on-screen drawing is actual size.

How It Works

How it works in three quick steps.

1

Choose the trim dimensions and orientation

Select a named sheet or enter custom physical width and height with their unit. Preserve defined order or choose portrait or landscape. Review the nominal trim dimensions before adding layout edges.

2

State layout edges and raster policy

Optionally add linked or independent bleed and safe margins, using the final orientation. Set whole pixels per inch, a rounding policy and the trim or bleed raster rectangle. Inspect all physical and integer-pixel results.

3

Save the complete dimension record

Copy text or LaTeX working, download dimensions and exact certificates as CSV, share active settings or print the calculation report to PDF. Report printing does not create an actual-size blank sheet or infer printer scaling.

Download & Print

Save dimensions and print a calculation report

Copy or share the active setup

Copy a full numerical summary or display-delimited LaTeX working. A versioned share link restores the selected sheet, orientation, active custom inputs, layout edges, raster policy and report preferences after validation.

Download a complete CSV record

The quoted UTF-8 file retains all physical unit rows, exact certificates, box dimensions, pixel counts and effective densities. Hidden unit tables and working remain in the complete export for independent inspection.

Print the selected report

Print / Save PDF removes form controls and supporting articles while retaining the dimension report and proportion diagram. Review page size and scaling in the browser preview. The printed report documents a setup; it does not export a blank sheet at the selected physical size.

FAQ

Frequently Asked Questions

What does the Paper Size Converter calculate?
It starts with a named nominal trim sheet or custom physical dimensions, applies the selected orientation, and converts width and height into common layout units. Optional edge settings derive an outward bleed rectangle and an inset safe-area rectangle. A separate raster section converts the chosen rectangle into whole pixel dimensions at your stated pixels per inch, with the rounding policy kept explicit.
Are A4 and US Letter the same physical size?
No. The A4 nominal trim dimensions are 210×297 mm210\times297\,\mathrm{mm}, while US Letter uses 8.5×11 in8.5\times11\,\mathrm{in}. They have different widths, heights and aspect ratios. Changing a selected paper name compares dimensions; it does not resize an existing document or determine how a printer will scale it. Check the trim result and the application's page setup when moving a layout between those sheets.
What is the difference between Tabloid, Ledger and orientation?
The Tabloid and Ledger catalog entries describe the same rectangular sheet with opposite defined width/height order. Native orientation preserves that distinction, including Ledger’s landscape order. Portrait places the shorter dimension first, while landscape places the longer dimension first. Custom dimensions follow the same rule. Bleed and safe-margin edge names apply after this orientation choice, so top and left refer to the final layout.
How do bleed and safe margins affect dimensions?
Bleed extends outside the finished trim and increases the artwork rectangle. Safe margins inset the trim and reduce the inner rectangle intended for important content. Link edges for a uniform amount or unlink them to enter all four sides independently. Opposite safe margins must leave a positive width and height. These are user-supplied layout assumptions, separate from a printer’s nonprintable area or a finishing provider’s specification.
Why are CSS pixels different from raster pixels at my selected PPI?
The CSS reference pixel has a fixed unit relationship: 96 pxCSS=1 in96\,\mathrm{px}_{\mathrm{CSS}}=1\,\mathrm{in}. Raster pixel dimensions instead depend on the physical rectangle and your chosen image sampling density. Changing raster PPI therefore changes the bitmap estimate without changing the CSS reference-pixel table row. Device pixels, printer dots and CSS reference pixels should not be treated as interchangeable quantities merely because an application uses the word resolution.
Which pixel rounding policy should I use?
Nearest rounds each positive axis to its closest integer, with exact halves rounded up. Round-up never produces fewer pixels than the unrounded request, while round-down can slightly reduce effective density. The report shows the resulting horizontal and vertical densities independently. A tiny physical sheet at very low PPI may round an axis to zero; the physical conversion remains valid, but that rounded pair is not a usable bitmap size.
Does selecting ISO B5 also cover JIS B5?
No. The catalog explicitly labels the ISO B series, whose nominal dimensions differ from similarly named JIS B sizes. Check the full standard or the printer dialog’s exact dimensions before assuming that a shared paper label means the same sheet. Custom physical dimensions are available when your required sheet is outside this catalog. The tool retains nominal dimensions rather than changing them to force an ideal mathematical aspect ratio.
Will Print / Save PDF produce an actual-size sheet template?
The print action saves a calculation report containing dimensions, raster policy, the proportion diagram and selected working. Its page size is controlled by the browser print dialog, so it is not a blank document with the selected physical trim size. Use the values to configure your layout application, or open a related graph-paper generator for a printable sheet. CSV and copied text retain complete numerical certificates, including sections hidden from the visible report.
About This Tool

About this Paper Size Converter

The Toolarithm Paper Size Converter translates nominal sheet dimensions into the units used for page setup and artwork planning. It preserves the original fourteen named choices, including A4 and Ledger, while extending the catalog to thirty-three explicitly labeled sheets. Custom physical dimensions cover rectangles outside the catalog. Defined order keeps the original width and height, while portrait and landscape arrange the axes before subsequent layout edges are applied.

The model keeps finished trim, outward bleed and inset safe area separate. Bleed and safe-margin controls can be linked for a uniform amount or unlinked for independent edges. Their unit is explicit, and safe margins must leave a positive inner rectangle. Those values are user-supplied layout assumptions. A nominal paper name alone does not establish a printer’s usable area, finishing requirement, paper tolerance or document scaling behavior.

Raster planning starts from either the trim rectangle or the complete bleed rectangle. The requested pixels per inch and integer rounding policy determine the whole axes, while the report retains unrounded requests and resulting effective densities. CSS reference pixels appear as a distinct fixed-unit table row. Printer dots and device pixels are not inferred from that reference. Tiny sheets at low sampling densities can produce a zero-pixel side under a chosen policy; the tool records that limitation while keeping the valid physical dimensions available.

Exact rational arithmetic preserves the declared decimal or fractional numerical model through conversion, layout boxes and pixel rounding. Accessible LaTeX and MathML present visible quantities, and server-rendered default results remain available before interactive code loads. Text and CSV retain complete numerical certificates and hidden report sections. The print action produces a calculation report with a proportion diagram and selected working. It supports checking and documenting a layout setup rather than creating an actual-size blank document or a calibrated measuring template.

Editorial Transparency

Who maintains this page

Ownership and review

Written and maintained by the Toolarithm editorial team. No review date is shown without a maintained editorial record. No independent professional review is claimed.

Methodology

Conversion factors are normalized to canonical units and checked in both directions. Exact definitions and offset formulas are preferred over rounded lookup values.

Read the editorial methodology

Dates and sources

Review dates change only after a substantive method or content check.

Finished sheet versus printed artwork

Treat paper size, imageable area, and pixel dimensions separately

A named paper size defines the finished sheet, not the printer's usable rectangle and not a raster file's detail. This converter keeps those concepts separate by showing physical dimensions first and making the 300-PPI pixel row an explicit planning estimate.

Representative sheet comparisons

The registry stores ISO dimensions in millimeters and North American dimensions through their inch definitions.

A4
210×297210\times297 mm; approximately 8.268×11.6938.268\times11.693 inches.
US Letter
8.5×118.5\times11 inches; 215.9×279.4215.9\times279.4 mm.
US Legal
8.5×148.5\times14 inches; 215.9×355.6215.9\times355.6 mm.
Tabloid
11×1711\times17 inches in portrait orientation.
Ledger
17×1117\times11 inches in landscape orientation.
A3
297×420297\times420 mm; two A4 sheet areas.

Understand the A-series relationship

ISO A-series sheets retain the same aspect-ratio system as successive sizes are obtained by halving the longer side, subject to the standard's integer-millimeter dimensions. That makes A4-to-A3 or A4-to-A5 scaling predictable.

North American Letter and Legal do not share the A-series aspect ratio. A document can therefore reflow, crop, or change margins when a print dialog substitutes Letter for A4 even though the two sheets look similar at a glance.

Calculate raster size from a declared assumption

The pixel row multiplies physical inches by 300. For A4, the inch conversion produces non-integer pixel values, while a raster image must ultimately use whole pixels. Round according to the export workflow and verify whether the application resamples.

Changing only a DPI metadata field does not create image detail. Pixel dimensions, physical output size, and resampling behavior must all be checked before a raster file is judged ready for print.

Add bleed and margins outside the finished-size result

The converter reports the trimmed sheet. If artwork extends through the cut edge, follow the printer's requested bleed specification and add it to both sides of each dimension.

Desktop printers often have non-printable hardware margins. A file that matches the sheet exactly can still be clipped or scaled unless borderless output is supported and deliberately selected.

Worked check: prepare an A4 raster reference

  1. 1Select A4 and keep the defined finished size 210×297210\times297 millimeters.
  2. 2Read the displayed inch conversion, approximately 8.268×11.6938.268\times11.693 inches.
  3. 3Use the 300-PPI row as a planning estimate, then choose whole-pixel export dimensions and confirm bleed, imageable area, and scaling with the target print provider.

Regional and print-production limits

  • The named size does not indicate paper weight, coating, grain direction, tolerance, printer tray availability, or finishing method. Those are separate production specifications.
  • Tabloid and Ledger share physical dimensions but reverse orientation. Software names can vary, so verify width and height rather than relying on the label alone.
  • Browser and PDF print dialogs can choose fit, shrink, or a substituted tray size. Use actual size or 100 percent and measure a test output when dimensional accuracy matters.

Sources and definitions

Continue the task

Related next steps

DPI and PPI calculatorRelate the chosen sheet to an actual raster's pixel dimensions.Printable templatesBrowse reviewed graph layouts by paper size.Length converterConvert custom margins, bleed, or sheet measurements.

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