Heat Capacity Calc
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100 calls/day, no card, no spam. Built by one person, in public.
About Heat Cap
Heat Cap was built for the moment you just need to handle this task and move on — no signup, no upload to a third-party server. The goal was to keep the path from "open the page" to "get the result" as short as possible. No mandatory account, no cookie wall, no upsell at every step. If you find yourself doing this regularly, the rest of the utility suite covers most adjacent tasks with the same approach.
When you'd reach for Heat Cap
You're hitting the daily limit of a paid SaaS and need a backup option for a single quick job.
Marketers and ops people whose primary tool is metered.
Stay productive without burning credits.
You need to handle a one-off task right before a meeting and don't have time to install anything.
Anyone working remotely on a borrowed or restricted machine.
Open the page, get the result, paste it into your doc — under a minute.
You're on a public or shared machine and don't want to leave traces of what you're working on.
Travelers, contractors, anyone working from a friend's computer.
Nothing is uploaded, nothing persists if you're not signed in.
You're cleaning up a folder of files that accumulated over a project and need to standardize them.
Designers, writers, and developers wrapping up deliverables.
Drop each file in, copy the output, move on.
Frequently asked about Heat Cap
- Does Heat Cap work on mobile?
- Yes, Heat Cap is fully responsive and tested on iOS Safari and Android Chrome.
- Are my files uploaded to a server when I use Heat Cap?
- Heat Cap processes everything in your browser using local APIs. Your files never leave your device.
- Do I need to create an account to use Heat Cap?
- No. Heat Cap works without any signup. We only ask for an email if you decide to subscribe to a paid plan.
- Is Heat Cap really free?
- Yes — Heat Cap is free for unlimited personal use, with no account required and no watermark on the output.
- What browsers does Heat Cap support?
- Every modern browser released in the last three years: Chrome, Firefox, Safari, Edge, Brave, Opera.