Free tools
Tools that answer one question, correctly
Interactive calculators and analyzers for engineering and marketing work. Every result shows its formula, its units and its assumptions — and basic use needs no account.
- 7 assets
- updated 2025-08
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Each of these has the inventory to justify its own page. Anything without it stays a filter here rather than a thin page of its own.
Tools
All tools
Every card states what the asset delivers, what it costs and when it was last updated.
Belt Speed Calculator
Belt speed from drive-pulley diameter and motor RPM, with gearbox and optional belt-slip correction.
- No signup
- Formula shown
- updated 2026-09
Free
Pulley Speed Calculator
Driven-pulley RPM and belt linear speed from two pulley diameters and driver RPM.
- No signup
- Formula shown
- updated 2026-09
Free
Belt Length Calculator
Geometric belt length for a simple open two-pulley path.
- No signup
- Formula shown
- updated 2026-09
Free
Conveyor Belt Roll Length Calculator
Estimated belt inventory on a roll from outside diameter, core diameter and thickness.
- No signup
- Formula shown
- updated 2026-09
Free
Solar Savings Calculator
Illustrative solar operating savings and simple payback from your own annual kWh estimate.
- No signup
- Formula shown
- updated 2026-09
Free
SEO ROI Calculator
Forecast organic visits, conversions and attributed revenue from a keyword opportunity.
- No signup
- Formula shown
- updated 2026-09
Free
Content ROI Calculator
Attributed revenue per 1,000 organic sessions and a revenue-based content return proxy.
- No signup
- Formula shown
- updated 2026-09
Free
Questions
Common questions
- Do the tools need an account?
- No. The calculators run in the browser and return the result immediately. There is no email wall and no result held back behind a form.
- Can I use the results commercially?
- Yes. The results are yours to use. What you should not do is present the tool itself as your own product.
- How are the free tools related to the paid assets?
- A tool answers one narrow question, free. When you need the data behind it, the supplier list, or the full method, that is a dataset, template or agent run — and each tool page links to the ones that continue the job.
- Something in a calculator looks wrong. What do I do?
- Email us with the inputs and what you expected. Corrections are applied and noted in the tool’s version history, because a wrong calculator is worse than no calculator.
Start with the task
Tell us what you need to get done.
Describe the calculation you need and find the closest free tool. Product requests also help decide what Newlii builds next.
Free calculators need no signup · Methods and limits are shown