Belt Length Calculator
Belt length for a two-pulley drive from diameters and centre distance.
Order the closest standard belt and let the adjustment slots absorb the difference. Wrap under ~120ยฐ on the small pulley invites slip โ that's what idlers are for.
Formula
Belt Length Calculator is a free belt length for mechanical and machine-design engineers โ instant, accurate and 100% client-side, with the governing formula and reference shown next to the result so the number can be defended, not just quoted.
About Belt Length Calculator
Belt length for a two-pulley drive from diameters and centre distance. The calculation implements L = 2C + ฯ(Dโ+Dโ)/2 + (DโโDโ)ยฒ/4C (Belt drive geometry; IS 2494). Order the closest standard belt and let the adjustment slots absorb the difference. Wrap under ~120ยฐ on the small pulley invites slip โ that's what idlers are for.
How to use Belt Length Calculator
- 1Enter Pulley 1 ร in mm.
- 2Enter Pulley 2 ร in mm.
- 3Enter Centre distance in mm.
- 4Read Pitch belt length, Wrap on small pulley instantly โ no submit button needed.
- 5Need US units? Flip the SI/Imperial toggle and every field converts.
Why use Belt Length Calculator?
- โImplements the standard formula โ L = 2C + ฯ(Dโ+Dโ)/2 + (DโโDโ)ยฒ/4C
- โReference cited on-page: Belt drive geometry; IS 2494
- โOne-click SI โ Imperial toggle โ values convert in place, physics stays in SI
- โLive worked example: the substitution recomputes from your numbers
- โRuns entirely in your browser โ nothing uploaded, free forever
Frequently asked questions
What formula does the Belt Length Calculator use?+
It computes L = 2C + ฯ(Dโ+Dโ)/2 + (DโโDโ)ยฒ/4C, per Belt drive geometry; IS 2494. The formula is displayed under the result along with a worked example substituted with your own inputs.
What should I keep in mind when using this calculator?+
Order the closest standard belt and let the adjustment slots absorb the difference. Wrap under ~120ยฐ on the small pulley invites slip โ that's what idlers are for.
Is this suitable for machine design coursework?+
Yes โ these are the exact Shigley/Machinery's-Handbook formulas, with the substitution shown step by step, so you can follow the worked example into your own calculation sheet.
Is the Belt Length Calculator free to use?+
Yes โ completely free, no sign-up, no limits. It runs client-side in your browser, so inputs stay private and results are instant even on slow connections.
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