You glanced at the clock, saw an appointment, alarm, or deadline set for 1:20, and now you want a straight answer: how much time is actually left? That’s what this post is for. No rambling backstory — just the method, some worked examples, and a couple of tables you can scan in five seconds.
Quick Answer
The time remaining until 1:20 depends entirely on your current time. Here’s the shortcut:
- Note your current time (hour and minute).
- Subtract it from 1:20 (using 13:20 if you mean 1:20 PM in 24-hour format).
- If the current time is later than 1:20, add 24 hours before subtracting — that tells you how long until the next occurrence of 1:20.
That’s the whole trick. Everything below just walks through it with real numbers so there’s zero guesswork.
Why “1:20” Is Actually Two Different Times
Here’s where a lot of people trip up. Clocks in everyday use are 12-hour, so “1:20” could mean:
- 1:20 AM — 20 minutes past 1 in the early morning (01:20 in 24-hour time)
- 1:20 PM — 20 minutes past 1 in the afternoon (13:20 in 24-hour time)
If someone tells you “meet me at 1:20” without specifying AM or PM, always confirm which one they mean. A calculation for the wrong half of the day will throw your answer off by exactly 12 hours — which is a pretty big miss for something you might set an alarm around.
How to Calculate Time Until 1:20 (Step-by-Step)
Let’s break this into a repeatable process you can use for any current time.
Step 1: Convert Everything to 24-Hour Format
This removes the AM/PM confusion entirely.
- 1:20 AM → 01:20
- 1:20 PM → 13:20
Do the same for your current time. If it’s 9:45 PM, that becomes 21:45.
Step 2: Subtract Current Time From Target Time
If your target time (1:20) is later in the day than your current time, just subtract directly.
Example: Current time is 11:00 AM (11:00), target is 1:20 PM (13:20).
13:20 – 11:00 = 2 hours 20 minutes
Step 3: If the Target Has Already Passed, Add 24 Hours
If it’s already past 1:20 for the day, you’re really asking “how long until 1:20 tomorrow.” Add 24 hours to the target time before subtracting.
Example: Current time is 6:00 PM (18:00), target is 1:20 PM (13:20), but that’s already gone for today. So we roll it to tomorrow: 13:20 + 24:00 = 37:20.
37:20 – 18:00 = 19 hours 20 minutes
Step 4: Handle the Minutes Carefully
When the minutes in your current time are higher than 20 (the minutes in 1:20), you’ll need to “borrow” an hour, just like regular subtraction with numbers.
Example: Current time is 12:50, target is 13:20.
13:20 – 12:50 = 30 minutes
Straightforward here since 20 minutes is more workable, but let’s try one where borrowing matters.
Example: Current time is 1:35 AM (01:35), target is 1:20 PM (13:20).
13:20 – 01:35 = 11 hours 45 minutes
To check this by hand: from 1:35 AM to 1:35 PM is exactly 12 hours. Since the target is 13:20, that’s 15 minutes earlier than 13:35, so subtract those 15 minutes: 12 hours − 15 minutes = 11 hours 45 minutes. Matches.
Worked Examples Table (Countdown to 1:20 PM)
Here’s a table showing how long is left until 1:20 PM from a handful of common current times.
| Current Time | Time Until 1:20 PM |
| 12:00 AM (midnight) | 13 hours 20 minutes |
| 6:00 AM | 7 hours 20 minutes |
| 9:15 AM | 4 hours 5 minutes |
| 11:00 AM | 2 hours 20 minutes |
| 12:45 PM | 35 minutes |
| 1:00 PM | 20 minutes |
| 1:20 PM | 0 minutes (it’s now) |
| 2:00 PM | 23 hours 20 minutes (next day) |
| 8:30 PM | 16 hours 50 minutes (next day) |
| 11:59 PM | 13 hours 21 minutes (next day) |
Worked Examples Table (Countdown to 1:20 AM)
Same idea, but for the early-morning version of 1:20.
| Current Time | Time Until 1:20 AM |
| 12:00 AM (midnight) | 1 hour 20 minutes |
| 12:45 AM | 35 minutes |
| 1:20 AM | 0 minutes (it’s now) |
| 3:00 AM | 22 hours 20 minutes (next day) |
| 9:00 AM | 16 hours 20 minutes (next day) |
| 1:00 PM | 12 hours 20 minutes (next day) |
| 6:30 PM | 6 hours 50 minutes (next day) |
| 11:15 PM | 2 hours 5 minutes (next day) |
Practical Scenarios Where This Question Comes Up
This isn’t just an abstract math exercise. People search “how long until 1:20” for very specific, everyday reasons:
- Setting an alarm for 1:20 AM to catch an early flight or wake up for a shift
- Waiting on a meeting or class that starts at 1:20 PM
- Timing a recipe or task where something needs to finish by 1:20
- Countdown to an event — a movie, appointment, or livestream scheduled at 1:20
- Medication or reminder timing, where you need to know the exact gap before your next dose or task at 1:20
In every one of these cases, the calculation is identical — you’re just filling in a different “current time” each time you ask.
Common Mistakes and Misconceptions
A few things trip people up more often than you’d expect:
- Mixing up AM and PM. This is the single biggest source of wrong answers. Always double-check which 1:20 you mean before doing any math.
- Forgetting to roll over to the next day. If 1:20 has already passed today, the countdown is to tomorrow’s 1:20 — not a negative number, and not “no time left.”
- Miscounting minutes across the hour mark. Subtracting minutes without borrowing correctly (like treating 13:20 minus 12:50 as “70 minutes” instead of doing proper time subtraction) leads to answers that are off by an hour.
- Assuming 24-hour and 12-hour times behave the same in subtraction. They don’t, unless you convert first. Skipping the conversion step is where a lot of manual math goes sideways.
- Ignoring time zones. If you’re coordinating with someone in a different time zone and they say “1:20,” confirm whose local time they mean before you calculate anything.
Why People Search This Exact Phrase
Queries like “how long until 1:20” are usually typed in a hurry — someone’s mid-task, glancing at a clock or a countdown timer, and just wants a number, not an explanation. It’s the same instinct behind searches like “how many hours until midnight” or “how long till 3pm.” People want:
- A fast, accurate answer without opening a calculator
- Confirmation of AM vs PM when it’s ambiguous
- Sometimes a countdown they can mentally track (hours and minutes, not just a total minute count)
That’s exactly why breaking the answer into a clean method — rather than a single static number — is more useful. Your “now” changes every time you ask, so a fixed answer would be wrong the moment you read it.
Related Time Calculations You Might Also Need
If you found this useful, here are a few related calculations that follow the exact same logic:
- How long until a specific hour (e.g., “how long until 3:00”)
- How many hours between two clock times
- Countdown to midnight or noon
- Converting 12-hour time to 24-hour time (and back)
- Calculating elapsed time between a start and end timestamp
- Time zone conversions when coordinating a call or meeting
All of these boil down to the same core skill: convert to a consistent format, subtract, and roll over to the next day if needed.
Conclusion
Figuring out how long until 1:20 really comes down to three things: knowing whether you mean AM or PM, converting both times into the same 24-hour format, and subtracting carefully, rolling over to the next day if 1:20 has already gone by.
Once you’ve got that method down, you can apply it to any target time, not just this one. Bookmark the steps above, and the next time a countdown catches you off guard, you’ll have the answer in seconds.
Frequently Asked Questions
How long until 1:20 PM today?
It depends on the current time. Subtract your current time from 13:20 (1:20 PM in 24-hour format). For example, if it’s 10:00 AM now, that’s 3 hours 20 minutes until 1:20 PM.
How long until 1:20 AM tonight?
Convert 1:20 AM to 01:20 in 24-hour format, then subtract your current time from it. If it’s already past 1:20 AM, you’re counting down to 1:20 AM the next day, so add 24 hours before subtracting.
What if it’s already past 1:20 today — how do I calculate the time left?
If 1:20 has already passed, you’re calculating time until 1:20 tomorrow. Add 24 hours to the target time (making it 25:20 in extended format) and then subtract your current time from that.
Is there a difference between calculating time until 1:20 AM versus 1:20 PM?
Yes — they’re 12 hours apart. 1:20 AM is just past midnight, while 1:20 PM is just past noon. Always confirm which one applies before doing the subtraction, since mixing them up gives an answer off by exactly 12 hours.
Can I calculate how long until 1:20 without converting to 24-hour time?
You can, but it’s easy to make mistakes with AM/PM boundaries that way. Converting both times to 24-hour format first removes the ambiguity and makes the subtraction far more reliable, especially when the countdown crosses midnight or noon.