Swing Speed to Shaft Flex Chart: What Flex Do You Need?

Choosing the right shaft flex is one of the most important equipment decisions you'll make. Too stiff and you'll lose distance and fight a slice. Too soft and you'll struggle with control and consistency.

The problem? Most golfers guess at their flex based on what sounds right rather than what actually matches their swing. This guide gives you a clear swing speed to shaft flex chart, explains how to measure your speed, and helps you dial in the right flex for every club in your bag.

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Swing Speed to Shaft Flex Chart

Here are the generally accepted swing speed ranges for each flex category, based on driver swing speed:

Ladies Flex (L): Under 60 mph — Typical carry distance under 150 yards

Senior Flex (A): 60–75 mph — Typical carry distance 150–180 yards

Regular Flex (R): 75–95 mph — Typical carry distance 180–220 yards

Stiff Flex (S): 95–110 mph — Typical carry distance 220–260 yards

Extra Stiff Flex (X): Over 110 mph — Typical carry distance over 260 yards

These ranges aren't absolute—they're starting points. Factors like swing tempo, transition speed, and release point all influence which flex actually performs best for your swing.

For a deeper dive into how flex affects your shots, see our guide on how to know what flex golf shaft you need.

How to Measure Your Swing Speed

You can't pick the right flex if you don't know your swing speed. Here's how to get accurate numbers.

Launch Monitor Testing

The most accurate method is hitting shots on a launch monitor. These devices measure club head speed directly and give you precise data. You can find launch monitors at most golf retailers and indoor simulators. Many driving ranges now offer bays with tracking technology. Club fitters use professional-grade monitors during fittings.

Even a single session gives you the data you need. Ask for your driver swing speed specifically—that's the number you'll use for the chart above.

Driving Range Estimate

If you can't access a launch monitor, you can estimate swing speed from your carry distance with a driver. A 180-yard carry suggests roughly 80 mph. A 200-yard carry suggests roughly 90 mph. A 220-yard carry suggests roughly 100 mph. A 240-yard carry suggests roughly 108 mph.

This method is less precise because it assumes solid contact and doesn't account for wind, altitude, or ball type.

Golf GPS and App Data

Some GPS devices and swing analyzer apps estimate swing speed. These vary in accuracy but can give you a ballpark figure if other options aren't available.

For more on using technology to analyze your equipment, check out how to test golf clubs with launch monitors.

Why Shaft Flex Matters

The shaft is the engine of your golf club. It stores and releases energy during your swing, directly affecting launch angle, spin rate, and shot direction.

What Happens During Your Swing

When you swing, the shaft bends backward during the downswing (loading), then snaps forward through impact (releasing). This load-and-release cycle adds speed and affects how the clubface delivers to the ball.

A shaft that matches your swing speed loads and releases at the right time, maximizing energy transfer. A mismatched shaft disrupts this timing, costing you distance and accuracy.

Too Stiff vs. Too Soft

If your shaft is too stiff: The shaft doesn't load properly during your swing. You'll see lower ball flight than optimal, shots that fade or push right, reduced distance, and a harsh, dead feel at impact.

If your shaft is too soft: The shaft loads too much and releases inconsistently. You'll see higher ball flight with more spin, shots that draw or hook left, inconsistent distance control, and a whippy, unstable feel.

One of the most common issues we see is golfers playing shafts that are too stiff for their swing speed. If you're slicing your driver, your shaft might be part of the problem. Learn more in our article on why you slice your driver but not your irons.

Flex Isn't Standardized Across Brands

Here's something most golfers don't realize: there's no industry standard for shaft flex. A "stiff" shaft from one manufacturer might play closer to "regular" from another.

This inconsistency means you can't assume all stiff shafts perform the same. A Fujikura stiff might feel different from a Project X stiff, even at the same swing speed.

What This Means for You

Don't get locked into a flex label. Focus on performance instead. Use the swing speed chart as a starting point, then test actual shafts to see how they perform for your swing. Pay attention to ball flight and feel, not just the letter printed on the shaft.

If you're between flex categories on the chart, testing becomes even more important.

Iron Shaft Flex vs. Driver Shaft Flex

Your iron swing speed is slower than your driver swing speed—typically 10-15% slower. But that doesn't necessarily mean you need different flex ratings.

Consistency Matters

Most golfers play the same flex throughout their irons for consistency. If you're a stiff flex in your driver, you're probably stiff in your irons too.

However, some players benefit from slightly softer flex in long irons (where you need more help launching) and standard flex in short irons (where control matters more).

Shaft Weight Differences

Iron shafts are typically heavier than driver shafts. While your driver shaft might weigh 55-65 grams, iron shafts often run 95-120 grams in steel or 65-85 grams in graphite.

This weight difference affects how the shaft feels and performs, independent of flex rating.

When to Move Up or Down in Flex

Your swing speed isn't static. It can change based on age and physical condition, swing changes and lessons, equipment changes, and fitness level.

Signs You Need Stiffer Flex

Consider moving to a stiffer shaft if your ball flight has gotten too high, you're hitting hooks or pulls more often, your distance has increased significantly, or shots feel out of control at impact.

Signs You Need Softer Flex

Consider moving to a softer shaft if your ball flight has gotten too low, you're hitting fades or pushes more often, you've lost distance, or shots feel harsh and dead at impact.

How to Test Shaft Flex Before Buying

Never buy clubs without testing the shaft flex first. Here's how to do it right.

Demo Days and Fitting Events

Manufacturer demo days let you test the same club head with different shaft options. This head-to-head comparison reveals which flex produces the best numbers for your swing.

Retail Fitting Sessions

Most golf retailers offer fitting sessions where you can test multiple flex options on a launch monitor. Even a basic fitting gives you data on how different shafts perform.

The cost for a basic fitting ranges from free to around $100. For a full breakdown, see our guide on how much golf club fitting costs.

DIY Testing

If you have access to clubs in different flexes, you can run your own comparison test at the range. Hit 10 shots with each flex and track carry distance, shot shape, and feel.

For more self-fitting techniques, check out how to fit your golf clubs at home.

The Bottom Line

Shaft flex directly impacts your distance, accuracy, and consistency. Use the swing speed chart as your starting point: under 75 mph driver speed suggests senior or regular flex, 75-95 mph suggests regular flex, 95-110 mph suggests stiff flex, and over 110 mph suggests extra stiff.

But don't stop at the chart. Get your swing speed measured, test different flex options, and pay attention to ball flight and feel. The right flex for you is the one that produces the best results, regardless of what letter is printed on the shaft.

Not sure what flex you're currently playing?

FitMyGolfClubs identifies your club specs from photos and analyzes whether your shaft flex matches your game. Download the app and see if your equipment is helping or hurting your performance.

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