--- title: "Segmented 90° Bend Calculator — Developed Length & Shot Spacing | BendBoss" description: "Segmented (big-radius) 90° bend calculator: developed length = 1.5708 × radius, degrees per shot and mark spacing for any number of shots. Worked example for a 24″ radius sweep." url: https://bendboss.app/segmented-90/ language: en last_reviewed: 2026-11-14 --- [BendBoss](https://bendboss.app/) › Segmented 90 # Segmented 90° bend calculator When a 90 needs a bigger radius than any shoe or factory elbow, bend it in shots: several small, equal bends spaced along the conduit. The arc's developed length tells you how much conduit the sweep uses, and dividing it up tells you where each shot goes. Last reviewed Nov 14, 2026 · Sources at the end of the page _Interactive calculator on the web page: https://bendboss.app/segmented-90/_ Equal shots approximate the quarter circle. ## The segmented 90 formulas Developed length = (π ÷ 2) × radius ≈ 1.5708 × radius Degrees per shot = 90 ÷ number of shots Spacing = developed length ÷ number of shots The developed length is a quarter of the circumference at the centerline radius — IBEW Local 903's Bending Book uses "multiply the radius by 1.57." It's the straight conduit the sweep consumes. ## Worked example: 24″ radius, 6 shots 1. Developed length: 1.5708 × 24 = **37 11/16″**. 2. Degrees per shot: 90 ÷ 6 = **15°**. 3. Spacing: 37 11/16″ ÷ 6 = **6 5/16″**. 4. Marks from the start of the sweep: 0″, 6 5/16″, 12 9/16″, 18 7/8″, 25 1/8″, 31 7/16″. ## Two common spacing conventions Dividing the developed length by the number of shots (what this calculator and the BendBoss app do) puts each shot at the middle of its share of the arc. Local 903's book divides by one less than the number of bends, so the first and last bends sit right at the ends of the arc — its example is a 4″ radius in 9 bends of 10°, 6.28″ ÷ 8 spaces ≈ ¾″. That spreads the sweep slightly wider. Either works; be consistent and check the finished radius against your layout. ## How many shots? More, smaller shots look smoother. Gardner Bender's guide caps hickey segment bends at 10° per bend, and Local 903 suggests keeping the spaces under about 3″ so the elbow stays smooth. Check the minimum bending radius for your conduit in NEC Chapter 9, Table 2. ## Common questions ### How do you calculate the developed length of a 90? Multiply the centerline radius by 1.5708 (π ÷ 2). A 24″ radius uses about 37 11/16″ of conduit. ### How many degrees per shot in a segmented 90? 90 divided by the number of shots: 6 shots = 15° each, 9 shots = 10° each. ### How far apart are the marks? Developed length ÷ number of shots. Some training books divide by one less than the number of bends; both are used in the field. ### Why do my segmented 90s come out short of 90? Springback and uneven shots. Bend every shot the same, check with a level as you go, and touch up the last shot. ## Sources * [IBEW Local 903, Bending Book rev. 2](https://lu903.com/wp-content/uploads/2017/06/Bending-Book-rev-2-full.pdf) * [nVent Gardner Bender, Hand Benders How-To Guide B-0040](https://file.ecmindustries.com/-/media/inriver/B-0040.pdf) **Every bend on this site, in one app** BendBoss does offsets, saddles, rolling offsets, stub-ups, kicks, parallel runs (mixed sizes), segmented and compound 90s — fraction keypad, bend diagrams and step-by-step walkthroughs. $25.00 once. No subscription, no ads. English and Spanish. [Get BendBoss — $25.00 once](https://www.paypal.com/ncp/payment/XJL85QN76KKT6)[See what's in the app](https://bendboss.app/conduit-bending-app/) ## Related bend guides * [90° stub-up & take-up](https://bendboss.app/90-degree-stub-up/) * [Compound 90](https://bendboss.app/compound-90/) * [Offset calculator](https://bendboss.app/offset-calculator/) * [Offset multiplier & shrink chart](https://bendboss.app/offset-multiplier-chart/) * [The BendBoss app](https://bendboss.app/conduit-bending-app/)