Water and wastewater · Worked step by step
How do you turn 350 GPM into gallons per day?
If math has never been your thing, you are in the right place. Try it on paper first, then we write it out with you, one small step at a time, and explain every step in plain words so you never lose the thread.
The problem
A pump runs steadily at 350 gallons per minute (GPM). How many gallons per day is that?
Grab a pen and paper first
Give it a real try on paper before you watch. If you get stuck, take a hint. If you go blank, that is fine, press play and we will walk it through together.
Watch it solved, with you
Every step is written out slowly and explained in plain words, so you always know what just happened. Nobody skips ahead and leaves you behind.
Press play and I’ll write it out with you, one small step at a time.
Every step gets a plain-words explanation here, so you always know exactly what just happened and why.
The written version, step by step
- 1
Write down what you know
flow = 350 GPM • 1 day = 1,440 minutes
- The pump moves 350 gallons every minute.
- We want a whole day. A day has 1,440 minutes (that is 24 hours × 60 minutes).
- Write both down.
Quick trick: Memorize 1,440. It is one of the most-used numbers in operator math.
- 2
Set up the multiply
GPD = 350 × 1,440
- If 350 gallons go by each minute, then in 1,440 minutes we get 1,440 times as much.
- "Times as much" means multiply.
- So gallons per day = 350 × 1,440.
Quick trick: Per-minute to per-day is ALWAYS × 1,440. No exceptions.
- 3
Multiply it out
GPD = 504,000
- Break 350 × 1,440 into easy pieces.
- 350 × 1,000 = 350,000, and 350 × 440 = 154,000.
- Add them: 350,000 + 154,000 = 504,000 gallons per day.
Quick trick: No paper? 350 × 1,440 is about 350 × 1,400 = 490,000. The real answer sits just above.
Remember this for good
To go from per minute to per day, multiply by 1,440, the number of minutes in a day.
There are 1,440 minutes in a day (24 hours × 60 minutes). "Per minute to per day" always means × 1,440. Burn 1,440 into memory; it shows up again and again.
Solve it fast next time
- GPM to GPD: multiply by 1,440.
- GPD back to GPM: divide by 1,440.
- If a problem gives per-HOUR instead, the day number is 24, not 1,440.
The answer: 504,000 gallons per day.