Swim Distance and Pace Calculator




Introduction: Swim Distance and Pace Calculator

I swim a mile three days a week, one problem given how repetitive it is I would lose count. In my case 36 (up and back 25 yard pool) laps are just over a mile. Almost all pools have Pace clocks (see picture) with any type of swim team, this is for those of us who train but are not on a swim team.

I have a counter I use that keeps track of laps and pace but it has too much glare to be any good beyond looking at my pace per lap when I am done. Being an engineer I unconsciously solved my problem. I extrapolated my single case solution to accommodate any one who swims distance in a pool.


Pace clock on the wall.

Step 1: Reasoning

As I got lazy in my swimming thinking about anything but my stroke, I found my time never got any better ranging from 33:40 – 34:15. Determined to get better I started looking at the pace clock just after the flip, I did some quick math in my head to determine that to swim a sub 33:00 mile (36 laps in my pool is greater than a mile by 120ft) I needed to swim an average of 55 seconds per lap. With that in mind each lap I tried to make sure the sweep hand on the clock appeared to move 5 seconds backwards with each lap to get the 55 second pace.

I further extrapolated that if I counted how many times the sweep hand passed the zero I could determine if I was on schedule. A good rule of thumb was to be gaining (for lack of a better term) about 1 minute every 10 minutes. That by 20 minutes I should be 2 and 30 to be close to 3.

Step 2: Example

I could not paste the table so I took a screen shot the col are a little off but you should be able to get it. here is an example.

For example if your goal is 33min/Mile:

Mile time, Pace, clock back/lap, clock back10min, 20min, 25min, 30min @mile mark

33:00, 55, 5, 00:50, 01:40, 02:05, 02:30, 03:00

You need to remember 3 things: start time (so you can go for a set time before checking and know when you are done), your goal pace at -5 seconds per lap, and keep track each time the sweep (second) hand passes 60/0 to count minutes. Given you will only vary a second or two per lap (at least you should if you try to keep pace, I start strong but by the third lap my pace does not vary much) the total time is not much of an issue.

I know if I go 3 minutes back in 33 minutes total I know I swam a mile and know my pace.

Now if the clock went back only 2:30 at 33min I know I should swim another lap to make it a mile, in any case until you know your “time zone” you swim keep going to the next 5 minute mark to make sure you get your mile as a penalty for not making your time. Soon you will find by keeping an eye on your pace you will improve to either reach your goal or find your current limit.

Step 3: PDF File and Excel

The PDF shows the results for 25-36 minute miles.

The excel file provided for those who want ot edit.

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    7 years ago on Introduction

    This would have been super helpful when I had to swim for my Divemaster (SCUBA) certification. I love it! I agree that those laps are super repeditive and really quite boring.


    7 years ago on Introduction

    Very nicely done! I love seeing this kind of numbers nerdery related to sports and athletics. Awesome stuff!