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時間計算機

時間と分を足し引きし、合計を時間・分・総分数で表示します。

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このツールの詳しい解説（使い方、例、よくある質問）は、現在英語のみでご用意しています。

What this tool does

Add or subtract one block of hours and minutes from another. The result is hours and leftover minutes, plus the signed total in minutes. This is duration arithmetic. It does not look up a clock, a date, or a time zone.

How to use

  1. Enter the starting hours and minutes. Both must be whole numbers, zero or greater.
  2. Enter the hours and minutes to add or subtract.
  3. Choose Add or Subtract, then press Calculate.

Examples

  • Two and a half hours plus 1 hour 45 minutes

    2 hours 30 minutes plus 1 hour 45 minutes is 4 hours 15 minutes, which is 255 minutes.

  • Subtracting more than the start

    1 hour 0 minutes minus 1 hour 30 minutes is minus 0 hours 30 minutes, which is -30 minutes.

Main features

  • Minutes of 60 or more are carried into hours.
  • A result below zero is marked minus and still shows the remaining hours and minutes.
  • Total minutes, so you can check the arithmetic.

How it works

Each side is turned into minutes, the second side is added or subtracted, and the signed total is split back into hours and leftover minutes. This is duration arithmetic. It does not look up a clock, a date, or a time zone.

Tips

  • Type 90 in the minutes box if you do not want to convert it to 1 hour 30 minutes first. The page carries the extra minutes.
  • Use the Date Difference Calculator when the question is days between two calendar dates.

Limitations

Hours and minutes must be whole numbers from 0 through 100,000. A blank box is rejected. Decimals and negative inputs are rejected. The page does not convert time zones.

See the disclaimer for what these tools do not cover.

FAQ

Is the Time Calculator free?
Yes. You can add or subtract hours and minutes here without paying or creating an account.
What if the minutes are 60 or more?
They are included in the total and then shown as hours plus a remainder from 0 to 59.
Can the result be negative?
Yes, when you subtract more than the starting duration. The page marks that result as minus.
Are these numbers sent to a server?
No. The hours and minutes are calculated in this browser tab. Tools Star Hub does not send those numbers to a server or save them in local storage.

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