SettingsSettings for this calculationUS
The total number of glass lites or windows to be set.
Count LITES, not windows. A sash divided into two panes is two lites and takes two pairs of blocks, because setting blocks carry the glass's own weight down onto the frame and every independent piece of glass needs its own support. Small lites need them as much as large ones; the block size changes with the weight, the need does not.
The number of setting blocks placed beneath each lite.
Standard practice uses two setting blocks at the quarter points beneath each lite; larger or heavier lites may use additional blocks per the glass manufacturer's or glazier's recommendation.
Total setting blocks needed
80 setting blocks
They open the calculator with your figures already in it
Window Setting Block Count Calculator: 80 setting blocks — shown in imperial, US market. The link sets both, so the result they see is the one on your screen.
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How this was calculated
Formula source(s)
- Total setting blocks = number of lites × blocks per lite, following standard glazing practice of two setting blocks placed at the quarter points beneath each glass lite
Inputs used
- Number of Glass Lites
- 40
- Setting Blocks per Lite
- 2
What this calculation does not cover
- The result is a count, not a size and not a load check. Setting block length, width and hardness are chosen from the weight and area of the lite and the bearing stress the block can carry, and a block narrower than the full glass edge will load only one pane of an insulating unit instead of the spacer and both panes; none of that is tested by multiplying lites by blocks, and the dimensions and durometer come from the glass manufacturer's glazing instructions.
- A single blocks-per-lite figure is applied to every lite in the batch, and the input accepts only two to four. A mixed order in which the oversized lites take four blocks and the rest take two must be run as two separate calculations and the totals added, and a lite whose manufacturer calls for more than four blocks cannot be entered at all. The total is an exact product, with no spare blocks added for units dropped, cut wrong or lost on site.
- Nothing here positions the blocks. The quarter-point placement the calculation assumes, the edge clearance the block sets between glass and frame, and the rule that a block must never sit across a weep hole or dam the glazing pocket are all outside the count, and a correct quantity fitted in the wrong place still traps water against the edge seal.
- Only the blocks that carry the lite on its bottom edge are counted. Side blocks and anti-walk blocks on operable sashes, top blocking, and the shims and spacers used to centre the glass in the pocket are separate items and are not included in this total.
- Block material is not considered anywhere in the calculation. An elastomer incompatible with the glazing sealant can stain the edge seal of an insulating unit or inhibit the cure of structural silicone, so the compatible compound has to be specified from the sealant manufacturer's compatibility data independently of the quantity.
Estimated cost — your price
This site holds no price list for this material — local prices vary too much to publish honestly. Enter your supplier's price and the result is costed with it.
Computed in your browser — nothing you enter is uploaded. Presented in US customary units and US trade terminology. Where a formula follows a published standard, that standard and its edition are cited beside it on this page; where none governs, the page says so. Local amendments override model codes — verify against the code in force where you build.
Sources checked 2026-09-02 · in the site-wide review of 2026-09-06 · v1.0.1
Regulatory standards & verification citations1
- Total setting blocks = number of lites × blocks per lite, following standard glazing practice of two setting blocks placed at the quarter points beneath each glass lite
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