"Swingweight Calculator+" DIY Precision Measuring In Excel: Normalized + Gripless Swingweight Options. Now with MOI

[J.Bex]

*** For the latest version, Rev.1, see the post on 4/20/25 in this thread.  I'm adding it to the top here too because I see people are downloading the Rev.0 file *** 

 

Swingweight_Calculator+_Rev.1.xlsx

 

------------------------

Rev.0 from 2023:

 

Update to the Excel sheet I'm now calling Swingweight Calculator+ (kind of a Disney+ homage):

 

Swingweight_Calculator_Plus_Rev.0.xlsx

 

The previous one is here:  https://forums.golfwrx.com/topic/1713548-newer-excel-swingweight-calculator/ which had quite a few downloads.  Btw the title "newer swingweight calculator" was homage to diselG's "new sw calculator" from a post in 2011 (link), which was pretty much an extension of Tutelman's swingweight table (link), and same for mine.

 

Main Update:

 

There are posts that pop up all the time regarding grip weight and swingweight.  It's a popular practice and recommendation on WRX to measure swingweight using a standard 50 gram grip, rather than measuring with a midsize or jumbo grip on.  And of course StuartG has explained to stop using grip weight to adjust swingweight just about a million times!  To add to that, here are Mr. Tutelman's own words:

 

 

To address that I added the option to enter your grip's weight and balance point (normally about 4" from the butt) - whatever size grip you have.  The calculator will spit out an equivalent or "normalized swingweight" as if you had a 50g grip installed instead.  It will be more accurate than the approximation that you do in your head (5 grams = 1 SW point, lose 2-3 SW points going to midsize,...).  I could a add a column for a gripless swingweight, which should be heavier by 9-10 SWP, but I felt the sheet is already a bit busy.  Tape wraps can be included in your numbers.

 

Also I adjusted formatting and protected cells to help prevent errors, so it's a little friendlier especially if the user isn't the most Excel savvy.  It should also be a little better if you use it on cell phone like I do with the Excel app.  Swingweight was moved next to the club description for this purpose.

 

As mentioned in the orange textbox to the right of the calculator:

 

***Please Don't use Cut/Paste or drag any of the number input cells as it will mess up cell references.  Copy/Paste, Clear, Delete are all OK***

 

The following are examples of the flexibility of this Excel calculator.

 

Example 1.  For the simplest use, just enter the total weight and balance point, same as online calculators:

My driver above is D3.9.   However this is with a midsize grip...

 

Example 2.  Same driver as above but I entered the midsize grip weight and balance point to see the "normalized swingweight" as if the club had a standard 50g grip instead:

That comes out to D5.6 - almost 2 points higher as you might've guessed.

 

Example 3.  Adding 3 grams to the head, enter 3 and the distance of the weight to the butt of the club (keep ruler parallel to the shaft, like the diagram shows in the sheet):

Regular SW D5.8, normalized D7.4

 

Example 4.  If you were to use a 3 gram lighter weight screw, enter -3 and the distance of the weight to the butt of the club:

Regular SW D2.0, normalized D3.7

 

Example 5.  To see the effective swingweight when choking down the grip 1 inch, enter 1, then see the swingweight number on the right:

Effective SW C7.3 (no normalization for grip size as this is probably the least important or cared for calculation).

-------

 

There are some recommendations in cell comments.  E.g. Balance the club on a blade with tape protecting the shaft; preferably measure in mm; weight scale precision to 0.1g; etc.

 

There are disclaimers and notes in the orange textbox.  E.g. Get a real scale for ease of use and less chance of user error... Don't be a slave to a specific swingweight number on different builds! 

 

Free DIY calculators like this are fine for the hobbyist.  Assembled measurements are much better than calculators deriving SW from general component lengths/weights.  Just take your time to be as accurate and precise as you can.  Then it will be very close, if not spot-on, to an actual calibrated scale.  Again the calcs are straight from Tutelman's table (D0.0 = 213.5 oz-in, 1 point = 1.75 oz-in).  As mentioned in the past, the SW numbers you get here will be identical to those in the online calculators of Hireko (link) and Okrasa (link), and a little different than Leaderboard (my least favorite haha, link).  If you're like me, spreadsheet form is much more useful for recording, and you're able to test various scenarios like shown above.  This spreadsheet goes to 500 lines, so it can be an ongoing log if you like, but just be careful if you print, to not print all 28 pages 😄.

 

At the end of the day you want to be consistent with your own measuring methods and application.  Use swingweight as you wish, but be informed of its origins, limitations, and people's interpretations / misinterpretations.  Btw my own swingweight numbers are definitely not as even or evenly progressed as you might think due to going mostly by feel, and not really caring to hit exact SW numbers because the clubs work and feel good.  Hope it's as useful for some others as it is for me to record and play around with numbers.

Edited April 26 by joostin
Added Rev.1 file to top. Updated title

[10undrbogey]

Good work, thanks! Tried out the grip weight normalizer, works 👍 great

[BREWMASTER95060]

23 hours ago, joostin said:

And of course StuartG has explained to stop using grip weight to adjust swingweight just about a million times!  To add to that, here are Mr. Tutelman's own words:

Club MOI changes via grip and shaft weight VS head weight.
Varying component weights changes club Balance point.

Edited February 13, 2023 by BREWMASTER95060

[BREWMASTER95060]

There was a group on Yahoo called spinetalk.

he and I actually exchanged a few emails about 20 years ago

very smart guy.

If a grip weighed 10 pounds it would be hard to ignore. 🙂

Edited February 13, 2023 by BREWMASTER95060
Fix

[J.Bex]

9 hours ago, BREWMASTER95060 said:

Club MOI changes via grip and shaft weight VS head weight.
Varying component weights changes club Balance point.

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Yes.

For club MOI, the equation would be I = Σ(m*x²) for every single point of the club (as if the club was broken into a million tiny pieces), with m as the mass of each tiny piece and x being the distance from each piece to the butt end.  That's done on computer model, or it can be derived physically with a pendulum period like Tutelman shows, or an MOI machine of course.

[MFBach]

16 hours ago, BREWMASTER95060 said:

Club MOI changes via grip and shaft weight VS head weight.
Varying component weights changes club Balance point.

 

6 hours ago, joostin said:

For club MOI, the equation would be I = Σ(m*x²) for every single point of the club (as if the club was broken into a million tiny pieces), with m as the mass of each tiny piece and x being the distance from each piece to the butt end.  That's done on computer model, or it can be derived physically with a pendulum period like Tutelman shows, or an MOI machine of course.

I always like to proceed comments like this by clearly stating that I’m absolutely not a physicist… but isn’t the idea the same?
 

Grip weight is distributed so closely to the “fulcrum” that, while mathematically recordable/significant, it’s not as distinguishable during play as a similar amount of weight distributed at the end of the club?
 

At the end of the day, we swing a club with the handle/butt, not the balance point or 14” from the end? I’m still not fully confident in MOI build changes and their affects, so the change in total weight may be more significant compared to standard SW measurements? 

[AlohaPineapple]

thank you! the prev version was super useful, looking forward to playing around with this one

Edited February 14, 2023 by AlohaPineapple

[Skrimpdelite]

Thank you for this. Looking forward to utilizing it

[J.Bex]

11 hours ago, MFBach said:

 

I always like to proceed comments like this by clearly stating that I’m absolutely not a physicist… but isn’t the idea the same?
 

Grip weight is distributed so closely to the “fulcrum” that, while mathematically recordable/significant, it’s not as distinguishable during play as a similar amount of weight distributed at the end of the club?
 

At the end of the day, we swing a club with the handle/butt, not the balance point or 14” from the end? I’m still not fully confident in MOI build changes and their affects, so the change in total weight may be more significant compared to standard SW measurements? 

You're correct.  We have:

- mass/weight

- torque (in the swingweight case, weight times the balance point's distance to a fulcrum)

- MOI (above post)

 

If weight is added right on the fulcrum of an MOI machine (end of the grip), the MOI doesn't change... but total weight still does.  Then the farther that weight gets from the fulcrum the higher the MOI.  Likewise with a swingweight scale (14" fulcrum).

 

The swingweight scale is basically a torque measuring device that was a "good enough" practical way to get close to an MOI match.  But yeah, even a perfect MOI match doesn't necessarily translate to a swing feel match because of the swing not being on a fixed fulcrum, and there are differences in club weights and torques.  Then you have differences in swing planes, ball position, swing effort, ...

[J.Bex]

Quick note for anyone that uses the spreadsheet:  If you need to adjust column width, row height, or other formatting that is locked, you have to unprotect the sheet.  Find the Unprotect button circled below under Review.  There's no password to unprotect, and that will allow you full access to play with the sheet however you want.

 

 

Excel on my phone doesn't have that option, so I would do it on desktop/laptop.

[J.Bex]

I'll do a comparison to see what happens when measurements are off, but first an example of measuring with tight precision.

 

Finding balance point

Best is to balance on a blade edge, with tape that protects the shaft and gives some friction to balance on.  Also get the club as horizontal as you can:

 

Mark a little score on the tape with the blade and a fine marker or pen.  Butt a ruler and the butt of the club against the same flat surface like a wall.  Tape measure is fine, just push the clip in if pushing against a wall, or make sure it's pulled out if pulling against the butt of the club.

 

This measures at 718.5mm (convert to 28.287").  Even if your ruler or tape measure only has 1/8" hash marks, try to break that down by half (1/16") or by quarter (1/32") as best as you can.

 

Weighing

Best to have a scale that measures to 0.1 gram.  If not +/- 1 gram is not bad and still better than if the scale is +/- 1 oz.

Make sure the scale is calibrated if you can.  Weigh; take it off to bring back to 0 or tare to 0; weigh again.

 

Enter both numbers in Calculator+

This club comes out to D2.6

 

Correct vs Off Measurements

Here's the iron above, correctly at D2.6, vs what happens if a measurement is off by the amounts shown in the descriptions:

 

A balance point measurement that is off by 1/16" is off by half a swingweight point (but that rounds to D2 instead of D3).  1/8" is off by 1.1 SWP.  Half a gram is only off by 0.1 SWP.  1 gram is off by 0.2 SWP.  1 oz is off by 1.1 SWP.

 

Again if you're not able or inclined to measure precisely, or you need something quicker or less error-prone, by all means get a real scale!  Otherwise if you can measure as precise and consistent as you see necessary, no worries if you don't have a scale.

 

Plus... as in Swingweight Calculator+ 🙂... with this you can calculate things pretty easily without having to physically try them on a real scale, and as shown in the 1st post, calculate things that online calculators can't without physically altering and redoing balance point and weight measurements.

Edited February 18, 2023 by joostin

[J.Bex]

Hot Off the Press

Swingweight Calculator+ Rev.1 has two new tabs:  Swingweight Without Grip, and MOI!

 

Download:

Swingweight_Calculator+_Rev.1.xlsx

Swingweight Without Grip

 

This has been a recommendation here, in which you would measure swingweight before putting a grip on, and assume that number is 9-10 swingweight points higher than when you install a standard grip (e.g. measure E0, subtract 9 points, for a final swingweight of D1).

 

We will calculate it instead.  Since there’s no singular “standard" set of grip specs, Calculator+ asks you to enter “your standard" in the yellow box – grip weight, grip CG distance to the butt, and grip cap thickness.  I prefilled the fields as 50g, 4”, and .25", but feel free to adjust.  Your measurements might be different, and you may want to include the weight of your grip and buildup tape. Your call.

 

Example

 

To measure grip CG distance, try to balance a grip on a blade.  Mark it and measure the mark to the butt end (balanced and marked on a little piece of tape below).  To measure the grip cap thickness, stick a shaft's narrow end in the grip until it bottoms out.  Mark it and find the difference with the grip's length.  The one standard grip I have lying around is used, but I'll use its measurements.  It weighs 47.9g (49.5g with double sided tape); its CG is 100 mm (convert to 3.94”) to the butt; and the grip cap is 5.5mm (.22") shown below.

 

 

 

 

 

Here are examples of clubs measured without grips.  The grip specs above were entered in the yellow box.

 

 

For these clubs, the swingweights without grips measure from D9.4 to E2.3.  The equivalent gripped swingweights calculate from D1.1 to D3.9 (these red numbers are your standard swingweights).  So with this particular grip, the swingweights are 8.2 to 8.4 points higher without the grip vs with the grip.

 

MOI Estimate

 

This has been a long time coming.  I took calculations based off of the “MBI/MOI" spreadsheet done years ago by Monte Dougherty.  What I liked from that was that he included the grip cap thickness and more importantly a more “correct" calculation for a shaft’s MOI vs the simple calculation that assumes a shaft is a uniformly distributed straight cylinder (I = 1/3 ML²).  His equation corrects for the actual measured CG of the shaft.

 

As a test, I modeled a shaft in CAD with different wall thicknesses from tip to butt, got the following MOI, and compared it to the simple calc. and Dougherty’s calc.  You can see how much closer his MOI calc is to the actual MOI.

 

 

In Calculator+, the grip uses the same equation as the shaft.  The head and all the other components that you can include are assumed as point masses.  You just need to enter each component’s weight, and then each component’s CG distance from the butt of the shaft.

 

Here's an example measuring for MOI of a dry fit wedge.

 

First I like to measure the grip specs like we did above - weight, CG, length, grip cap thickness.  Next measure the cut shaft weight, length, and its CG distance to its butt.

 

Shaft CG distance to its butt is 440mm (17.32") here:

 

 

Measure the head weight of course:

 

For the head it’s best if you find and mark the CG on the face (balance the clubhead face down on a pen)... short of finding the CG in 3D space that is. 

 

Here's my driver's lovely CG:

 

When dry fitting, measure the head's CG distance to the butt of the shaft.  I like to keep the ruler parallel to the shaft because that's like how MOI is measured on an Auditor.  This measures 941mm (37.05"):

 

 

Measure similarly for other components like the ferrule, whose CG distance to the butt of the shaft here is about 845mm (33.27"):

 

Here is the MOI of this dry-fit wedge after plugging in all the numbers.  Comes out to 2,990 kg-cm².  Zoom in:

 

 

All the measurements for each club go on one line, and the MOI will update when each component’s numbers are filled.  Again I like starting with the grip to establish the grip cap measurement, then going to the shaft, then the head, etc.  It's laid out in that order.  But if you filled out only the head info, for example, you can see what its own contribution is to MOI.

 

Like with swingweight measurements, the result is only as accurate as your measurements are, so be as precise as you can.  Also like with the swingweight calculators, you can see what adjusting weight will do to the MOI.  Want to see what 10 grams of lead tape added to the shaft does to MOI?  Or if you subtract 4 grams from the head?  Just plug in the numbers.

 

Usage

 

Please note this is meant to be opened in Excel.  I know the formatting will change if you open in Google Sheets, for example, but it should all still work.

 

I removed locked cells, so everything is editable.  I also only froze the top headers, because I found it annoying on the previous Calculator+ to zoom in on my phone when the left columns were frozen.

 

Can you use this MOI Calculator for a club that’s already assembled?  Yes but it will be a more rough estimate.  You should at least know the head weight, then you can eyeball the head CG to measure that distance.  You can estimate where the shaft's midpoint is, and use that for it’s CG distance, along with its estimate cut weight.  It’s better of course if you measure all these things beforehand.  For a DIY MOI of a fully assembled club, you would be better off rigging a setup for Tutelman's pendulum period method.  https://www.tutelman.com/golf/design/swingwt4.php

Final Thoughts

If you read my calculator threads you know I recommend having a real swingweight scale.  However when you DIY and find balance points, it opens up possibilities to do math more easily.  When you know component weights and CGs, you can do even more math.  That’s what all this is, paired with moment balance equations (below) and MOI equations.  So input good data and let Calculator+ do the math. ✌ 

 

A little behind the scenes chicken scratch on the phone 🙂

 

Edited April 21 by joostin
Added pics and comments

[Howard_Jones]

@joostin

Very nice stuff

 

Edited April 20 by Howard_Jones

[SAM_PGA]

Bravo! 🤩🤩🤩

 

As I enjoy the KISS method for building clubs, I’ve always targeted ungripped SW at +9 point on every club.  I don’t have all of the fancy equipment for my home DIY club repair shop but my builds are usually spot on and efficient because of this SW target method. 

[J.Bex]

8 hours ago, SAM_PGA said:

Bravo! 🤩🤩🤩

 

As I enjoy the KISS method for building clubs, I’ve always targeted ungripped SW at +9 point on every club.  I don’t have all of the fancy equipment for my home DIY club repair shop but my builds are usually spot on and efficient because of this SW target method. 

 

Great!  Yeah when I recently reshafted my clubs I made sure to record ungripped swingweights to have as a baseline.  Then I can change grips however I want, and can choose to either record swingweights/MOI with different grips or just ignore variations from grip to grip.

[SAM_PGA]

On 4/21/2025 at 6:01 PM, joostin said:

 

Great!  Yeah when I recently reshafted my clubs I made sure to record ungripped swingweights to have as a baseline.  Then I can change grips however I want, and can choose to either record swingweights/MOI with different grips or just ignore variations from grip to grip.

Yup.  Generally in my experiences, std grip/weights will be good to go.  Depending on feel, larger/heavier grips could warrant some lead tape but no more than just 1 SW point.  Heavier grips, I tend to ignore the change in actually SW values.  LARGER grips change the feel in your hands as you swing the club, usually necessitates the addition of lead tape in a SW point or two to adjust to desired feel but THIS is just feel, ignoring actually SW value.  

Edited April 26 by SAM_PGA

[Kingcat990]

Fantastic table 

[J.Bex]

11 hours ago, SAM_PGA said:

Yup.  Generally in my experiences, std grip/weights will be good to go.  Depending on feel, larger/heavier grips could warrant some lead tape but no more than just 1 SW point.  Heavier grips, I tend to ignore the change in actually SW values.  LARGER grips change the feel in your hands as you swing the club, usually necessitates the addition of lead tape in a SW point or two to adjust to desired feel but THIS is just feel, ignoring actually SW value.  

 

👍 Tweaking by your own feel FTW

[J.Bex]

Sharing the gram scale and ruler that I currently use. 

 

Scale:

 

$33.88 (USD)

(Amazon Link)

 

 

Nice inexpensive scale that measures to 0.1 gram and comes with its own 100g calibration weight in a little compartment on the bottom.  I've had it for a year, and I just charged the internal battery for the first time with the USB-C cord, but it didn't even need a charge.  You can also use optional AAA batteries.  Useful for packages and anything else of course. 

 

I got it for the above features, esp. for the price with a calibration weight.  It hasn't needed recalibration, even checking with 800.0g weights.

 

I reluctantly just removed the blue protective film on top that I thought looked cool (it actually came with another flim on top of that), so it doesn't look like my pics above anymore.

 

48" Ruler:

 

$6.99

https://www.harborfreight.com/48-in-aluminum-ruler-69365.html

 

Picked this up at Harbor Freight several years ago because it measures mm on one side and inch on the other, and you won't find a better price.  The inch scale only has 1/8" hash marks, which isn't good for measuring precise, so the mm side is most useful.  I'll use the inch side for club lengths, but that's pretty much it.

 

In Swingweight Calculator+ I'll always just enter a mm measurement in a cell like the following.  If something measures 941 mm, enter in the cell:  equals 941 divided by 25.4 (the exact conversion since 1" = 25.4 mm) to let Excel calculate it.  =941/25.4

That'll show as 37.047".

 

Depending what ruler you have available or can find, I'd recommend either:

 

- A ruler with mm (0.039") hash marks.  You can even eyeball a measurement in between as 0.5mm (0.020"), so pretty darn precise.

 

- A ruler with 1/32" (0.031") hash marks.  You can eyeball a measurement in between as 1/64" (0.016").

 

- With 48" rulers that only have 1/8" or 1/16" hash marks, use a secondary smaller ruler that has 1/32", to line up over your main ruler to measure more precisely.

 

So with these items, you can DIY Swingweight for $41 - at precise detail if you measure well, and do all the things Calculator+ can do in this thread.  Even if you have a real swingweight scale, it can be useful to do this sometimes because Calculator+ can do things your scale just can't.  Online calculators can't do what it can do either... unless they start copying 😉.