How we check facts and build our tools

How the tools compute

Each tool's formula, assumptions and limits are written on its page in plain text, with two or three worked examples. The same code that runs the tool in your browser is used by an automated test that recomputes every example and table before a page can be published, so a figure on the page cannot drift from what the tool calculates. The seating chart maker, for instance, counts seats, auto-fills and shuffles with the same functions its tests check.

Where the figures come from

Table capacities, floor areas, dance floor rules and spacing come from the published guides of rental companies and event businesses; the 36-inch accessible route from the ADA standards, and the occupant-load figure from the International Building Code. Each page names its sources with the date we checked them, and a Basis line under each table or rule says whether a figure is a source's, our arithmetic or our own choice.

How we use AI

The pages' text and the tools' code are drafted with AI tools, from the sources each page lists, and the narration and sound effects in our tool videos are AI-generated (ElevenLabs; the music under them is written by our own code). Before anything is published, a separate AI review that did not write the draft checks each claim against its named source and the tool's code, and the site's owner approves the page. Any AI-generated illustration is labeled as such on the page.

Corrections log

Every correction made after a page is published is recorded here with the page, what changed and the date. No corrections yet: the site went live on October 28, 2026. Report an error at hello@seatchartly.com.

Checks before launch

Before launch, each page was checked by a separate AI review that had not written it, against its listed sources and the tool's code: the seating chart maker on October 23–28, 2026, the home page on October 24–28 and the guests-per-table calculator on October 24–28. The main figures corrected before launch:

• Round tables for more than 12. The maker's fit note said no rental guide lists one; Stuart Event Rentals lists a 96-inch round for 12–14, and the note now names it for 13 or 14 seats.
• Banquet tables in the layouts. The basis said every layout used the top of the rental range; banquet tables seat 4 a side, 8 per 8-foot table, the low end of the 8–10 range, and the basis now says so.
• Bright Event Rentals' dance floor rule. One section for every 4 guests was described as a 15 × 15 ft floor for 100 guests (25 sections of 3 × 3 ft); Bright's own 100-guest example uses 4 × 4 ft sections and sizes it as 20 × 20 or 16 × 24 ft, about 400 sq ft.
• Small round tables. For 2 to 6 guests the maker's note named only a 48-inch round, though Party Rental Ltd. and Stuart Event Rentals list smaller rounds (24 to 42 inches); it now names them.
• Several charts in one browser. The maker's page first said each chart keeps its own Undo history; Undo starts afresh when another chart is opened, and the page now says so. It also offered 20 charts without a caveat: near the 1,000-guest limit a browser's few megabytes for a site hold fewer, so the page now says charts are kept as far as the browser's storage allows.
• Colors for every section. The home page first said a band gets each section in its own color; the maker has eight group colors, which repeat after the eighth, so the page now says only that the legend counts each section.
• A claim about guests. The home page first said guests ask where to sit in the last half hour; nothing supported it, and the sentence is gone.
• The calculator's video. Its narration said the room's length and width check that everything fits; the calculator compares floor areas, and the narration now says it checks the floor area.
• Your own floor plan. The home page first said you could begin with your own floor plan; the maker places tables on a plain grid, not a scaled floor plan, and the page now says to place your own tables.
• Spacing between tables. The maker's Spacing view first marked a gap between two tables under 36 inches as narrow, borrowing the ADA's 36-inch clear width for a walking route, though the tables' own chairs stand in that gap. Between tables it now marks only fine (54 inches or more, from Stuart Event Rentals and Planning Pod) or tight, and the 36- and 24-inch figures apply only to aisles between blocks of chairs.
• Round tables of your own size. The first version judged any other diameter by 24 inches of table edge a guest, which is stricter than the rental companies' own counts (their 60-inch round seats 8–10, about 23.6 inches each at 8); a size a company lists is now judged by that listing, and any other size against the listed sizes either side, so a bigger table never gets a worse verdict.