Show HN: While the world builds AI Agents, I'm just building calculators
117 comments
·February 22, 2025chrismorgan
Some comments, based purely on https://www.calcverse.live/calculators/bmi.
• Keyboard accessibility is suffering, because the buttons aren’t associated with a form. Most notably, pressing Enter when one of the text boxes is selected doesn’t do anything. You should put everything inside a <form> element, and then if you’re using <button>, decide whether it’s type=button or type=submit.
• A tad more subjective, but actual radio buttons are better than the buttons you’ve used for Metric/Imperial.
• As it stands, they lack a keyboard focus indication. (And the submit button has poor focus indication.)
• People don’t talk about heights in inches. They talk about them in feet and inches. You want to be able to accept feet and inches as two separate inputs. Not everyone who knows that their height is X′Y″ knows that means 12X+Y inches, and even more will make a mistake in calculating that, or just give up.
• If you switch between metric and imperial, and there’s a number in height or weight, it should probably convert the number to the chosen scale.
• If you just recalculated on input rather than on submit click, the experience would probably be smoother.
• Colour contrast on “Category: Overweight” is definitely too low. “Category: Normal weight” is also a little too low; underweight and obese are fine.
• Consider sometimes what related information might be useful. Every BMI calculator lists the categories, but something I somehow haven’t ever seen and yet which would be very useful for giving someone something to aim for is a mapping: for a given height, what weights do the categories correspond to? e.g. for 200cm, underweight = 0–74kg, normal weight = 74–100kg, overweight = 100–120kg, obese = 120–∞kg. Consider visualisations too. And mentioning what the calculation actually is that is being performed. Calculations are simple. Presenting them well is the harder bit.
adi_hn07
Thank you so much for the detailed feedback! I'll take some time to go through these points and fix the issues, and will revert back here asap.
adi_hn07
I have implemented most points, except the 2nd and last ones. I felt its better to have buttons as they are easier to click. I'm figuring out how to implement the last point.
redbell
Somehow related: “A calculator app? Anyone could make that”: https://news.ycombinator.com/item?id=43066953
karparov
A suggestion for your speed converter: different sports use different units which your converter could support as well.
A few examples:
Running usually measures pace in minutes per kilometer or mile. That will be extra fun for you since it wouldn't be 4.33333 min/km but would be written as sth like 4:20 min/km.
Swimming uses min/100m or sec/100m.
Rowing uses min/500m.
If you add these then I'd be using this a lot!
adi_hn07
Thanks for the great feedback! I've added pace units to the speed convertor, do check it out and let me know if you need any changes. You can send all requests at the contact form on the site too: https://www.calcverse.live/contact
Will aim to implement it within 24 hrs. Thanks again!
4887d30omd8
You're not the only one. I recently took up running and didn't particularly like any of the existing running pace calculators, so I made my own: https://calcubest.com/health/runningpace
And then kinda realized that there were others I wanted to have, and a few I thought others might want, so I added more.
A calculator is simple enough that it's fun to work on one when I need a break from something more complex but want to be able to do something other than doom scrolling. So now every couple of weeks I add another one.
megadata
To anyone thinking of starting running but either doesn't know where to start or thinks he can't do it, look up "couch to 5k".
It's a free NHS audio program that guides your phase so that in 9 weeks you can do a 5k run.
4887d30omd8
I can second this. That's the program I started with. I'm now training for a half marathon using https://www.baa.org/races/baa-half-marathon/train/leveltwo and I've shaved like a minute off my mile pace while increasing my milage from 6 mile runs to 12 mile runs.
There's lots of programs for running and most of them seem good for improving performance.
anshumankmr
No strength training in this?? I have been training legs for years along with runs (treadmill runs/uphill runs etc)... only problem my timing for the half marathon has gone down from 2h35 to 2h38 and then I had an accident last year which made me unable to run most of the second half of last year which has made things a lot tougher for me to train :(
kjhughes
Suggestions:
- Fix your certs to not lose traffic when Chrome (at least at the default security level) puts up a scary "Your connection is not private" warning for net::ERR_CERT_AUTHORITY_INVALID and requires an override to proceed to your site.
- Fix whatever reputation damage has caused you to be classified as a phishing site: https://phish.opendns.com/main?url=www.calcverse.live
adi_hn07
This is really strange, what can I do to resolve this? My SSL cert is valid. My site doesn't collect or store any sensitive information at all.
RandomDistort
I doubt the cert issue is on your end, it appears whenever OpenDNS (Cisco Umbrella) tries to intercept any site when it blocks it.
adi_hn07
Thanks for your reply. Will try to contact OpenDNS.
stanleykm
One calculator I’ve come to love over the years is Numi. I keep it open all day every day and it does a pretty good job of bridging the gap between the typical skewmorphic calculator app and scilab or python. It’s a text based calculator that allows you to declare variables and do unit and base conversions and save and load your work. No graphing though unfortunately and i dont think it really has much in the way of plugin support.
Anyway not to say your calculators arent useful op, i just think that something that can be open on the desktop is more useful than something that is hidden in a chrome browser tab.
lubujackson
Haven't tried Numi, but I made a calculator with variables as a side project on a whim: https://calc.li/ - it is online, but there is no backend and you can save the whole page as an offline file if you want, using localStorage for state.
ay
Typing “2”, “+”, “3” on an iPhone in Safari gets it to display “23+”, which doesn’t appear correct to me ? Looks cute otherwise.
saransh29
I also love numi on my mac! a similar online alternative is https://numbr.dev/
lelandfe
If I calculate something, hit back in my history, and then return, what I had entered is wiped out.
If I enter text into this HN comment box, hit back in my history, and then return, what I've typed is maintained.
ninalanyon
BMI calculators are dangerous tools in uncritical hands. Here is a link to the UK NHS page that provides such a calculator but only after it has described some of the limitations:
https://www.nhs.uk/health-assessment-tools/calculate-your-bo...
megadata
Yep, according to BMI, Schwarzenegger has always been obese af.
ikhare
On the topic of calculators. I discovered Figr[1] on HN a while ago, and it really helps when doing one off multi variable thing, like helping a customer estimate their bill etc.
Kudos on building this. I occasionally search for these on Google and am always disappointed by the mess. Bookmarked.
adi_hn07
Thank you so much for the bookmark! Means a lot. Figr looks great, will take inspiration and guidance from it. Thanks for the suggestion.
sjakati98
Sick work! I built this small calculator I was using to estimate Redis usage when I'm working on some projects: https://redisestimator.fly.dev
fragmede
A tiny bit of feedback, for you about unit conversion. I don't want to convert 47383974 seconds to hours, I want to know that it's 1 year, 6 months, 0 days, 18 hours, 51 minutes, and 18 seconds. I don't want to know that 7492837 inches. that's 624,403.0833 feet, but what I really want is for it to say 118 miles, 454 yards, 1 foot, and 1 inch!
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ndr42
Looks nice. Feedback: I was trying to enter "1000$" and "12%" (in the loan calculator) and it rejected my inputs ("Loan amount must be a positive number" and "Interest rate must be between 0 and 100") - could you just make it a bit more forgiving, if the units $ or % are included in the user input?
I figured I needed to work on my coding skills before building the next groundbreaking AI app, so I started working on this free tool site. Its basically just an aggregation of various commonly used calculators and unit convertors.
Link: https://www.calcverse.live
Tech Stack: Next, React, Typescript, shadcn UI, Tailwind CSS
Would greatly appreciate your feedback on the UI/UX and accessibilty. I struggled the most with navigation. I've added a search box, a sidebar, breadcrumbs and pages with grids of cards leading to the respective calculator or unit convertor, but not sure if this is good enough.