Try quickly typing 1 + 2 + 3 into the iOS Calculator. I bet you won’t get 6.

I came upon this Reddit thread and thought, “Impossible. This can’t be true.”

But yes, it is. Try this yourself. When you hit the plus sign for the second time, the calculator app goes into some odd state. Not sure if this is intentional, or a bug, but either way, this is not what you’d expect.

The good news? PCalc gets it right.

UPDATE: Looks like this is an animation lag issue and goes back at least through iOS 9, possibly earlier. Also, Apple employee #8 weighed in about filing a radar.



  • Will Taylor

    It’s hit or miss for me. Also, it seems to depend on whether or not one is accessing it via a locked phone or an unlocked one.

  • James Hughes

    It seems to depend on how fast I do it. This is on iOS 10.3.3. If I type it slowly, it works. Type it fast and it messes up, sometimes…

  • malhal

    I get 23 WTF. Apple can’t even code a calculator without bugs now?

  • Jim_Perry

    The addition button will not register another hit until its “highlight mode” turns off from the previous operation.

    • James Hughes

      That makes sense and fits with that I wrote about the speed of typing in the digits.

      • GS

        Form over function, literally. Issue persists with the latest beta. Don’t know how universal this is, but the calculator widget on the Mac has reintroduced an old bug. Calculator works fine but when you switch away from notification center for more than a few seconds it forgets your total, when you come back it shows 198,447.397

        • David Stewart

          This almost certainly isn’t an form over function issue but just a bug due to sloppy implementation/testing.

          • I concur. It’s a bug, not a design flaw.

          • GS

            Totally. I was being facetious. Very sloppy indeed, and really no excuse. Better to leave the calculator out.

    • Gordon Weir

      The Return of Pentium Math?? Bwa-ha-ha!!

  • JimCracky

    Works fine for me.

  • ChuckO

    Works for me first time I do it. Then it becomes inconsistent.

    Also, Notifications on the lock screen sometimes the text is outside the container. I’ve gotten the same News notification multiple times over the last couple of days. That happened twice.

  • jmas

    The real worry for me is: how this kind of malfunction pass inadvertently through Apple’s internal testing, and also developer beta and public beta programs? I suppose that someone at Apple is responsible for the Calculator app. Do they test their own apps? And we are not talking about an obscure and hard to trigger bug.

    • GS

      These bugs were noted. Low priority fix to Apple I guess?

    • Sigivald

      Testing speed-dependent things is exceedingly hard.

      This is not a bug where “1+2+3 always fails”; it’s one where “1+2+3 fails if it’s fast enough relative to the underlying hardware”.

      Meaning if you’re doing, say, automated testing in an emulator, either you slow all your tests down to be sure you’re catching anything, or you … don’t catch speed-dependent problems, meaning you have a slower test-develop-test cycle.

      And as GS suggests, “this is a problem only if you go really fast” isn’t likely to be a high priority in a freebie calculator whose target user isn’t Mr. Speedo.

      People who want super fast calculation are very likely to get a dedicated serious calculator app – or a real calculator or a PC if only for superior tactile feedback.

      • jmas

        There is no need to type “really fast” in order to trigger this bug. Even using an iPhone 7 Plus.

  • Hazel Frederick’s Ghost

    Works fine for me. Latest OS, iPhone SE 128. No matter how fast I type or what mode I’m in.

    • Hazel Frederick’s Ghost

      Tried it on my friend’s phone. Seems what’s happening is it’s not registering the tap on the + after 2.

  • It does indeed seem to havve to do with the iOS 11 animations. If you try to work with the keypad while still animation keypresses, the calulator gets confused. This is a painful interface fail.

    Fie on thee, Apple for prioritizing “shininess” over usefulness. awaits bug fix

    • wince

      And a systemic fail. Reported in early betas and ignored. A calculator that can’t calculate was ignored. It Just (Doesn’t) Work™.

  • PCalc is cool. I prefer CalcBot.

  • Totally unsurprised that somehow a free plug for PCalc made it’s way into todays stories.

  • John Kordyback

    Soulver is my fave. CalcBot & PCalc are also sano choices.

    Basically, I like buying good software from independent dev shops.

  • nutmac

    Instead of fixing this bug, I wish iOS would add a system wide setting called “eliminate animation” that cuts down all animations to zero (e.g., unlock, calculator button click, app launch, home screen exit).

  • vaguely

    Try 1 + 2 ++=