--- title: Copy Length & Page Estimator｜Mai Strategy ナレッジアカデミー lang: ja source: https://mindsprt.dev/ja/tools/copy-length-estimator/ --- # Copy Length & Page Estimator > Paste the copy and see roughly how many pages it fills at your page size and type size, before deciding what to cut Paste your copy, set the page size, type size and line height, and the tool works out characters per line, lines per page, and roughly how many pages it fills. The page count is a range rather than a single number, because one CJK character to one square is a typesetting fact while Latin letter widths vary by typeface, so the 0.5em average carries error. The most useful output is the flag for a last page under 5% full: that usually means trimming a small amount of copy saves a printed page, which is the most worthwhile edit in the document. This is an estimate, not typesetting. Headings, images, tables and line-breaking rules are not counted, and final pagination still comes from InDesign. ## How to Use 1. Paste the full copy into Paste your copy, then pick a size under Page size, such as A4 or A5 2. Adjust Type size, Line height, Margin, Columns and Gutter to match the real layout 3. The estimated page range appears immediately, along with characters per line and per page 4. If the last-page-under-5% warning shows, trimming a little copy will pull it back to a full page ## Method & Assumptions Characters per line is the column width divided by the character width, floored; lines per page is the text height divided by type size times line height, multiplied by the column count. Gutters are deducted from the text width first. Character widths fall into three classes: CJK characters and full-width punctuation occupy one square at 1.0em, which is a typesetting fact; Latin letters count as 0.5em; half-width digits and punctuation match Latin. Spaces count as half-width. Full-width punctuation is counted as CJK. Missing it costs only a few characters on one page, but across a long document it adds up to a whole page. Page counts round up. One character over is one page more, which is the reality of printing. The result is a ±12% page range rather than a single figure, because the Latin width is an average. That is where most of the error sits, so copy that is mostly Chinese estimates more accurately. Page presets cover A4, A5 and B5 plus 16-up and 32-up from the Shiroku and Kiku systems, using the same cut derivation as the print unit converter. Everything runs in your browser; pasted copy is never sent to a server. ## Use Cases - A4 with 20mm margins at 10pt and 1.5 line height gives 48 full-width characters per line and 48 lines per page, about 2,304 characters a page. - Switch the same copy to two columns with a 6mm gutter and each line holds fewer than half as many characters, while the total line count doubles. - Moving from 10pt to 12pt cuts page capacity noticeably, which is worth estimating before deciding to print more pages for readability. - An estimate of five pages where the last page is only 3% full triggers a red flag: trimming a short passage brings it back to four. - Estimating before quoting gives you the order of magnitude for paper and press time, without waiting for layout to finish. - Marketing hands over copy for a booklet locked at 8 pages, so design runs it through the estimator to find the character ceiling and flags the overflow for marketing to cut or move online ## FAQ ### How accurate is the estimate? Close, for copy that is mostly Chinese, because one character to one square is fixed. A high proportion of English introduces error since letter widths vary by typeface, which is why the tool gives a ±12% range rather than one number. ### Why not just give a single page count? Because a single figure invites people to treat an estimate as settled. A range prompts you to check; a point value does not. ### Are headings and images counted? No. The tool models plain body text flow only. With headings, images, tables or generous paragraph spacing, the real page count runs higher. ### Does it account for line-breaking rules and punctuation compression? No. CJK line-breaking rules and punctuation compression shift actual capacity slightly, which sits inside the stated error range. ### Can I quote from this page count? Use it for order of magnitude, not as the final basis. Formal quotes should follow the actual pagination from finished layout. ### Is my pasted copy uploaded? No. Everything is computed in your browser and nothing is sent to a server. ## Limitations & Disclaimer - This is an estimate, not typesetting. It models plain body text flow only, with no headings, images, tables, paragraph spacing or page-break handling. - Latin characters use a 0.5em average width. Real typefaces run wider or narrower, and this is the main source of error. - Line-breaking rules, punctuation compression and hyphenation are not implemented, so actual CJK capacity varies slightly. - Margins are uniform on all four sides, with no support for binding margins or asymmetric inner and outer margins. - Final pagination comes from layout software such as InDesign. This tool does not replace it. Updated: 2026-08-15 · Method version: v1.0.0 --- > HTML version: https://mindsprt.dev/ja/tools/copy-length-estimator/ > MINDS — 麥思印刷整合有限公司 · https://mindsprt.dev