Calculating My Golf Handicap

I started playing golf in 2017. Before that, I had hacked my way through a total of about 15 rounds in high school, college, and grad school. Last summer, I played over 150 rounds, mostly at the local course where I am a member. Its a 9-hole par 3 course where an unlimited membership costs $300/year. I consistently shoot 66-70 for 18 holes (5-9 over par), but the league says my HC is 3. I play Mizuno blades (6-PW), a couple of hybrids, 2 wedges, and do not own a driver.

Yesterday, I shot 87 (15 over par) at Northern Pines GC in Kalispell, a nice links-style course in Kalispell. It was raining, windy, 42 degF, and that was my first time playing there. In perfect conditions, I might have scrubbed 3 shots off the total. At Bandon this past winter, I shot 92, 92, 89 in good conditions on Dunes, Pacific, and Trails.

Over the past year, I've tried to play as many different courses as possible in order to both improve my course management skills and establish a Golf Handicap. In the table below, I used scores from 17 courses I recently played in Washington, Oregon, Idaho, and Montana to calculate my "Handicap Index" = 6.5. However, Handicap Index is not Handicap. It is used in the equation below to determine Handicap on a specific day for a specific course:

Slope Rating / 113 x 6.5, rounded up to nearest whole number

For example, if I play the following in good weather conditions...

Bandon Dunes (Slope = 133) 133/113 = 1.77 x 6.5 = 7.7 <-- My handicap for Bandon Dunes

Bandon Trails (Slope = 129) 129/113 = 1.14 x 6.5 = 7.4 <-- My handicap for Bandon Trails

Shuksan (Slope = 131) 131/113 = 1.16 x 6.5 = 7.5 <-- My handicap for Shuksan

Polson Bay Championship (Slope= 122) 122/113 = 1.08 x 6.5 = 7.0 <-- My handicap for Polson Bay CS

North Bellingham (Slope = 112) 112/113 = 0.99 x 6.5 = 6.4 <-- My handicap for North B'ham

Silver Fox (Slope = 58.1) 58.1/113 = 0.51 x 6.5 = 3.3 <-- My handicap for Silver Fox

I'm still not sure what my Handicap is, but I know it is more than 7 and less than 12. According the the online calculator using the following data, my handicap is 7 at the local course (Polson Bay Championship).

There is no way I could shoot better than about 85 at Bandon Dunes. Certainly not consistently. Therefore, I think the above calculations overestimate my golfing skills. For example...

In May 2020 I shot an 84 (12 over par) at the Polson Bay Championship Course (par = 72, slope = 119).

In October 2020 I shot an 83 at Polson Bay.

In August 2020 I shot 76 at Wildhorse Plains GC (par = 72, slope = 109), a personal best score.

In September I shot 83 at River's Bend GC (par = 72, slope = 109).

I could not have cut more than 3 shots off my score during any of these rounds by better putting, avoided mis-hits, or improved course management.

A handicap of 9 is a reasonable estimate for my game right now, despite what the calculator says. Purchasing a driver and switching from blades to players distance irons might help lower that number a couple notches. The Mizuno 921 Forged irons and the TaylorMade P7MC irons look really nice. Not sure about which drivers to try yet.