SW1 Racquet Swingweight Machine

(14 customer reviews)


In stock

SKU: SW1 Category:


The SW1 allows you to quickly and accurately measure the swingweight of racquets.

  • Oscillates about a vertical axis to determine swingweight independent of racquet mass and balance.
  • Uses the gyroscope sensor in your phone to measure with high precision. The companion app is available free in the Apple App Store.
  • More compact and portable than any comparable device.
  • Group measurements and see summary statistics. Displays the difference between groups to estimate twistweight.
  • Adjusts to your work area: configure it for left or right racquet release, and place your phone on either side.
  • Scan the NFC tag on the SW1 with your phone to open the app. If you use more than one SW1, it selects the scanned device. (This features requires iPhone XS or later or an Android phone with always-on NFC scanning.)
  • Calibration object included. It is based on a retractable extension pole with a permanently-attached end weight. Swingweights in the fully-collapsed and fully-extended states are marked on a wrap-around label. (Announcement)

To use the SW1, you will need:

  • An iPhone 7 or later – or – a phone running Android 8.1 or later with NFC capability and a physical gyroscope sensor. Android phones with non-standard form factors (flip, folding, etc.) probably will not fit securely in the SW1.
  • Approximately 4,000 4.5 mm (.177 cal) steel BBs to fill the device. In the US, a package of 6,000 BBs is available from many retailers for ~$10 (i.e., Amazon, Walmart). The SW1 is much easier to package for damage-free shipping when unfilled and can be filled easily without tools.

The plastic components of the SW1 are 3D-printed in PETG, which is tough, durable, chemical-resistant, and heat-resistant.

Related Links

Video: Briffidi SW1 Introduction

User Guide

Video: Briffidi SW1 Getting Started

Briffidi SW1 iOS App

Briffidi SW1 Android App

Blog Post: Effect of Orientation Error on Racket Swingweight Measurement

Blog Post: Racket Twistweight from Spinweight and Swingweight

Blog Post: Briffidi SW1 Linearity Testing

Blog Post: Effect of Leveling on Briffidi SW1 Measurements

Video: Briffidi SW1 One Gram Accuracy Test


Video: Fix This Anytime You Buy a New Racquet by TennCom (featuring the SW1)

Questions & Answers

Q: Why is the SW1 not available pre-filled with BBs?

A: A filled device would sell for ~$70 USD extra, to cover the cost of BBs, protection parts, packaging, and time resolving shipping damage. Shipping would also cost more. BBs are widely available in the United States for ~$10 USD, and filling the SW1 is easy to do with no tools.

Q: BBs are difficult to get in my country. Can I use something else?

A: Yes. The BBs are used as ballast, so something similarly small and dense should work. The BBs required to fill an SW1 have a mass of ~1.35 kg, so that should be your target. One customer used small screws. That mass of lead fishing weights may work. Sand or common pebbles will not work, as they’re much less dense than steel.

Q: What happens if Briffidi ceases to exist?

A: The SW1 will still work. The app will continue to function; it does not contact a backend server. If the SW1 will no longer be supported, I will publish the app source code and the hardware design.

Q: How accurate is the calibration object?

A: I estimate that the marked calibration values are accurate to within ±0.6 kg·cm². The values are determined by swingweight measurement after calibration with a pair of reference rods. The length and mass of the reference rods are measured as part of each calibration.

Q: How often should I recalibrate the SW1?

A: If you move the SW1 to a new location, you should re-level and recalibrate it. I have marked the spot where I use mine, so I can place it back in the same spot and avoid re-leveling. You should recalibrate if the temperature changes significantly. For a typical racket, the measured swingweight increases by ~0.09 kg·cm² per °F (~0.16 kg·cm² per °C). Otherwise, it’s not necessary to re-calibrate except occasionally to verify that nothing has changed. When measuring racquets, I typically only take a quick measurement of the calibration rod with weight to make sure it’s close.

Q: Why does SW1 calibration require measurement of  two known swingweights?

A: Two calibration measurements are required to subtract out the moment of inertia of the phone. It allows you to use any phone in whatever case you want (as long as it fits in the cradle securely). Of course, that means you should recalibrate if you add/remove a case or other mass to/from your phone.

Q: I broke something, can I get replacement parts?

A: Yes. I haven’t had to replace much, so I don’t have published spare parts. Please send a message to support@briffidi.com, and I will work with you to get your SW1 back in service.

Additional information

Weight 2.0 lbs
Dimensions 10 × 9 × 8 in


14 reviews for SW1 Racquet Swingweight Machine

  1. Tim K (verified owner)

    I’ve had excellent experience with the Briffidi SW1. I’m a recreational player who likes to have matched racquets in my bag and also likes to play around with different set ups from time to time. I got sick of bothering my local shop to use their Dunlop SW machine and using the various phone apps to estimate swing weight. I’ve gotten very accurate results that compare to much more expensive machines. Set up/calibration was very easy using the youtube video as a guide. I highly recommend the Briffidi SW1.

  2. Irvin Fuchs

    I’ve had very consistent results measuring SW and TW with the SW1 machine. I’ve found because of its light weight and portability it can move around from time to time. But as long and I calibrate the machine each time it is moved I can get excellent repeatable results.

  3. From the Talk Tennis Forum

    Power Player wrote: (link to source)
    Yeah, its really well cut. Like everything fits together like a glove. Its that 3d printed plastic but you can tell he put a lot of thought into it. For example the top lid of the casing for the bbs fits in so well that its almost like one seamless piece when put back together.
    The phone holder is also really cool. Accomodates a case or no case with no issue.
    It was clearly designed by an engineer who knows what hes doing.

  4. From the Talk Tennis Forum

    tim-ay wrote: (link to source)
    i really am impressed with this machine. that we are even talking about TW is incredible. and to think SW is almost too easy, lol. insane.

    just a great product – hats off to bfroxen

  5. From the Talk Tennis Forum

    PrinceYonex wrote: (link to source)
    Just wanted to jump in here to say that @bfroxen has offered amazing customer service. The moment he saw that I was getting higher-than-expected swingweights, he reached out to me and started to troubleshoot the issue. In short order he figured out what the issue was and immediately offered to send a new calibration rod (incidentally, there was nothing wrong with the build of the original one, just a single measurement typo that was throwing off the calibration process).
    For those who are interested in purchasing the sw1 but a little uncertain about it because this isn’t coming from a big brand, I can reassure you that build quality and customer care are excellent here. There’s an advantage when you are dealing directly with the guy who built the instrument and the app, not with a company rep.

  6. From the Talk Tennis Forum

    mad dog1 wrote: (link to source)
    It’s very well thought out, designed and engineered. Highly recommend.

  7. From the Talk Tennis Forum

    Kozzy wrote: (link to source)
    I’ve been trying, with extremely limited success, to match/customize my own racquets for years. I know see the #1 problem was that my SW calculations were absolute garbage. I’m sure they don’t have to be, but I clearly sucked at it. Thanks largely to the SW1 (and the TWU customize tool), for the first time ever, my changes actually hit the mark! I was aiming for 328 SW on two different racquets, and I got it! Holy cow. So easy. I’m sure that a real racquet pro would not be impressed, but they pretty much feel the same to me, and I don’t think I can tell the difference. Did it again with another set of frames as well, and got equally good results, in less than an hour! So amazing to have a simple, easy way to measure the swingweight that works every time, even for a clod like me.

  8. Thomas (verified owner)

    I wanted to customize my tennis racquet and wanted to measure swing weight. I was intimidated by the SW1 at first, thinking this wouldn’t require a lot of math to get accurate results, but that is not the case. This device is set up in a foolproof way. It works like a charm. Very pleased.

    • Brian Fitzpatrick

      I just noticed that I can reply to a review. Thanks for the review, Thomas.

  9. Fred Lam

    This setup have been for my small shop “circle-of-friends” type application. The entire setup is super easy to manage and it’s nice to be able to store away. Measurements are super consistent, taking all the guess work out. I highly recommend for anyone from DIY beginners to tennis nuts who looks to tinker.

  10. Max Treharne (verified owner)

    This is a really great little device – I am seriously impressed. Really consistent results and so much easier than trying to calculate swingweight manually as I was before.

    It made it all the way to the UK in a week too.

  11. Roy Peterka (verified owner)

    I was curious about this thing, and have often wondered about swing weight of my different racquets. Calculating SW without a machine is nearly impossible to do in a reproducible manner. I ordered a couple of weeks ago, and have had a chance to use it. Setup was easy after I actually read the instructions. The machine is solid and well made. I can understand why it is $250. I am glad I took a leap of faith and bought one. One thing that is important in calculating SW is making sure that the face of the racquet is oriented vertically. Any deviation from vertical increases SW (at least on this machine).

  12. B. Ko

    Agree with all the reviews. I took a leap of faith, not just because of positive reviews, but after reading all the materials Brian has posted. I could easily see that he is not really in this for the money. He is just another tennis nerd, like us, who happens to be a brilliant engineer with a touch of OCD. From the instructions to the product itself, you can see that he is a guy who pays a great amount of attention to details. The device itself is really well made, and I was amazed at how precise it was. Unfortunately, I can’t speak for the accuracy as I do not have a gold standard, but the precision (if you are like me, who is also a bit OCD, and has to follow all the steps) is remarkable. Highly, highly recommended.

  13. Kevin Le (verified owner)

    Does a job for a fraction of the price.

    For hardcore tennis enthusiasts this is a must have in addition to a balance board. Finding my swingweight actually helped improve my game as it made me realize I play much better with a lower swingweight so I can match all future racquets to that level.

  14. From the Web

    Jonathan at perfect-tennis.com wrote: (link to full review)
    The Briffidi SW1 is a game changer for measuring the swingweight of a tennis racket. It does exactly what it advertises and feels well made.

Add a review

Your email address will not be published. Required fields are marked *