← All comparisons

Dome design tools we'd pick, by job — 2026

Not a league table. Each tool below was given the same dome — 20 ft · 3V · 5/8 sphere — by hand on a recorded date, and each pick names the job the tool is good at. Every tool named here was run; anything we haven't run is a category, not a name.

One entry below is our own product. It's labelled, it's last, and it lists what we're worse at.

  1. 1. For strut lengths, quickly

    Desert Domes calculator

    Strut calculator·Free; the site asks for donations and carries advertising.

    One screen, one radius, three cuts of counts, and it has been right for twenty years.

    Matches DomeSketch to the thousandth of a foot

    Also listed in the builders directory (unpaid, unranked). That listing and this page are separate: the directory never mentions this ranking, and this page judges the tool alone.

  2. 2. For any measure but the diameter

    Domerama 3V calculator

    Strut calculator·Free to use in the browser; no account.

    Start from a strut you already have, a floor area or a height, and every other value follows; weights and slab quantities in the same table.

    Matches DomeSketch to the thousandth of a foot

    Also listed in the builders directory (unpaid, unranked). That listing and this page are separate: the directory never mentions this ranking, and this page judges the tool alone.

  3. 3. For timber cut angles

    Geo-Dome 3V tool

    Strut calculator·Free tool; the site sells dome plans, kits and a book.

    Mitre angles to the half degree on the same page as the lengths, from a builder.

    Matches DomeSketch, shown to fewer decimals

    Also listed in the builders directory (unpaid, unranked). That listing and this page are separate: the directory never mentions this ranking, and this page judges the tool alone.

  4. 4. For geometry beyond Class I

    Acidome

    3D constructor·Free in the browser, donations invited; an offline version is offered.

    Octahedral, Class III, Kruschke, frequencies to 18, beam cut lengths, .obj export — the widest geometry range of the tools we ran.

    Counts match; lengths reported differently
  5. 5. For understanding the numbers

    Simply Differently — Geodesic Dome Notes

    Notes with calculators·Free; donations invited.

    Chord factors, bending angles, face angles and lath-cut optimisation, explained.

    Matches DomeSketch to the thousandth of a foot
  6. 6. For Sonostar hubs

    Sonostar Hub calculators

    Kit calculator·Calculators and configurator are free; the company sells hub kits.

    Their calculators deduct their hub width; nothing general does.

    A different geometry variant — not like for like

    Also listed in the builders directory (unpaid, unranked). That listing and this page are separate: the directory never mentions this ranking, and this page judges the tool alone.

  7. 7. For designing the dome as a building — our own entry

    DomeSketch — our own entry

    Design studio·Free; no account. The "Get the full plan" button is not for sale yet.

    Openings, pad, rainwater, materials and five build methods on one shape, saved as a link. Everything it does not do is listed on its entry.

    • Class I icosahedral only, 1V–8V: no octahedral, no Class II or III, no Kruschke or Mexican subdivisions (Acidome, Simply Differently).
    • No bevel, dihedral or mitre angles and no timber cut lengths net of a joint (Geo-Dome, Acidome).
    • No reverse calculation from a strut length (Domerama, Desert Domes); no lath cut optimisation (Simply Differently).
    • Feet and inches only in the interface; millimetres only in the STL export.
    • Prices and mix yields are placeholders and the page says so; the materials estimate is rough.
    • No hub cut deductions for any specific connector (Sonostar).

Categories we haven't run

CAD plugins and scripts (SketchUp, Rhino/Grasshopper, Fusion 360, Blender)

What to look for: Whether it makes a true Class I geodesic (chord factors you can check against the reference tables) or just a subdivided sphere. Whether struts are solids with real cross-sections and end cuts, or only lines. Whether the base ring is trimmed to a cut you can build on.

How to verify at home: Build a 3V 5/8 dome of radius 1 and read the three edge lengths: they should be 0.34862, 0.40355 and 0.41241. If they are not, the plugin is not making a Class I icosahedral dome.

Places to look: SketchUp Extension Warehouse searches for "geodesic"; Grasshopper definitions shared on the Rhino forums; Blender's built-in Add Mesh: Extra Objects → Geodesic Dome.

Kit makers' own configurators

What to look for: Whether the numbers are for their connector only (usually yes, and that is the point). Whether the configurator ends in a quote or a checkout — it is a sales tool, which is fine if you are buying from them. Whether you can get the strut list out without ordering.

How to verify at home: Ask for the strut count and hub count for a 3V 5/8 dome: 165 and 61. A different total means a different geometry, not a mistake.

Mobile dome calculator apps

What to look for: Which frequencies and cuts they cover. Whether the chord factors match the reference tables. What they charge and whether the numbers are behind the payment.

How to verify at home: Same test as the plugins: radius 1, 3V 5/8, compare the three lengths to the reference tables.

Runs made 2026-09-20 · prices verified 2026-09-20 · candidates reviewed 2026-09-20 · a person did every check; nothing here was scraped. Entries older than 90 days say so rather than disappearing.

Every page here says when it was last checked; a stale entry keeps its date rather than being quietly changed. A corrections address will go here once there is one.