How to convert emitter GPH to IN/HR

I am trying to figure out how to convert drip emitter GPH flow rate to in/hr required by Rachio zone advanced settings. There is an old thread about that where someone posted a link to an excel-based calculator but the link is dead. Rachio support refuses to help and suggested I hire a professional landscaper to give me answer!

Can one figure it like so? I have four emitters, 1 GPH each, watering a 6’ x 2’ container. That is 1728 sq in. One gallon = 231 cu in. In one hour these four emitters deliver 924 cu in of water (i.e. 1 in of water over 924 sq in) over 1728 sq in. So is the nozzle inches/hr 924/1728 = 0.53 in/hr?

Maybe @dane can have that excel file uploaded on the Rachio servers so that we can bring it back to life. I have a copy of it if that is something that can be done!

Not saying your math is wrong, as it looks like it might be fairly accurate…but the calculator is slick!

If you use the calculator in the link you provided, it does all the work for you. The information you need to know is GPH per plant (if each plant has 3 2gph emitters, then enter 6), the gallons you want to apply per watering (use the chart to figure canopy size and vegetation type).

Hi @tmcgahey. I will look into this!

Meanwhile can you please share with me at

Why is @azdavidr not mentioned? It’s his work. Perhaps he still has a copy he can reupload.
That being said @dryheat122’s math checks out
4 GPH / (6’ x 2’) - Wolfram|Alpha (

@dryheat122, @tmcgahey, @Gene

Sorry for the delayed response on this. I don’t get Rachio Community alerts as often as I used to for some reason, and I was just out of the country for a bit as well. I’m working with @franz to get the link fixed. Thanks for the interest. Hopefully we’ll get the link working again shortly!

@azdavidr, the man, the myth, the legend.


@dryheat122 @tmcgahey @Gene

OK, that link should be fixed. I took the opportunity to fix a stale link or two as well. I’m glad to hear people still find the drip calculator useful!


I’m sure of the 1st part, not the 2nd or 3rd though. :wink:

I hope all is well @tmcgahey and @Gene. It’s been a while since I’ve had a chance to dig around these posts. It’s good to see that some of you guys are still around these parts helping out! I hope the spreadsheet is helpful to you @dryheat122.


Yes thank you. I used it to tweak my shrubs watering. It did not help with the main issue I originally came for, which is figuring out how to set up values for evenly-spaced emitters in a known volume (tomatoes growing in a horse trough). After making my brain hurt for a while I think I got that figured out, but now the system is overwatering, as noted in another thread I just posted, so trying to figure out how to fix that.

Do you know how many gallons you want to deliver per watering? If so you should be able to use the calculator but adding up the overall GPH in the trough and plug that in.

The soil might need amendments to promote draining. Tomatoes do best in a well-draining soil and prefer moist, but not wet conditions. A metal trough will retain moisture longer than a porous one.


Rachio still hasn’t added the option to use GPH?