Seam Allowance App

night morning

Seam Allowance app setting

As a metric user, one of my pet peeve when using certain sewing patterns are the seam allowance conversion. I couldn’t seem to remember what are the equivalent of 5/8″, 1/3″, 3/4″, 1/4″ and so on in centimetres. Sure I can use Google to find out that 5/8″ is 1.5875 cm, and then I would round this number to 1.5 cm.

It is not so easy the other way around though. When someone asked me what 1 cm seam allowance is in imperial, Google told me that it is 0.393701 inch. And how was I supposed to know that this number is close to 3/8″? I’m not good at mathematics, you know.

One day I told my husband about this and he said, “How about using an app for that?” That’s a great idea, except that I couldn’t find an app designed specifically for this purpose. In my simple sewing world, 5/8″ is 1.5 cm and vice versa, I don’t want all those little numbers. I wished that such app existed.

Luckily, the great thing about having a programmer for a husband is that he can make you an app for your needs. So my husband spent several weekends and came up with this Seam Allowance app!

This is a very simple app designed specifically with this one purpose, and that is how I want it. To convert a measurement, you just drag the slider and the app will show the rounding numbers. The numbers are based on the guidelines on sewing machine throat plate. You can set the metric on top or imperial on top and set the schemes to dark or light.


If you’re an iPhone/iPod user, you can download the Seam Allowance app for free here!

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  • Claire

    Thank you very much for this app. As you i need grpaphical drawing for the conversion. Thanks you Sir to think about poor sewers !

  • Sarah

    Thanks for this great app. Just downloaded it. I always have that problem of having to convert the measurements so this is a great help and i’ll be passing it onto my sewing friends.

  • Janet

    Fantastic app! Thanks so much…

  • Tina

    Thank you so much for this app! It’s great!

  • ElleC

    I just downloaded it! It is so simple and yet so brilliant! Thank you to you and your husband! ♥

  • Michelle

    What a GREAT idea! I often keep blogs for sewing tips and ideas, but I think this is the most practical one I’ve seen yet. Tell you hubby thanks from sewers all over the world!


    That’s so great! Thanks 🙂

  • redkatgal

    You have a special guy there! Wish I could use it as when I tried to download to my older than dirt iPhone, I could not without updating to IOS7. 🙁 Will have to remember this app when I ever get to upgrade. Tell your hubby thanks soooo very much.

    • You’re welcome! Hope you can use the app later! 🙂

  • Good idea! I’m an app developer myself, and I can definitely appreciate it as someone who sews as well.

  • Mae Wilson

    I have downloaded this app, and I think your husband is very clever! Please tell him “thank you” from me.

    • Thank you for trying out the app!

  • pugglette

    Hi Novita,

    Thank you for this app! It’s very useful, intuitive, and attractive! I grew up using imperial and know that best but I prefer using metric for sewing, so this is a great tool.

    • Glad that it is useful! 🙂

  • Super cool thanks