Convert a real spreadsheet time value
A spreadsheet time value represents a fraction of a day. To express that duration in hours, multiply it by twenty-four. If A2 contains a genuine numeric duration of 8:30, the formula =A2*24 returns 8.50 when the result cell is displayed with two decimal places. Format the output as a number rather than a time.
A cell can look like a duration while actually containing text. Multiplying an unrecognized text value may produce an error or depend on regional parsing. Check the source cell type before applying the formula. The downloadable CSV example uses numeric day fractions and formulas so you can inspect both the stored value and its expected hour result.
Preserve durations longer than a day
For accumulated durations, use a source display format such as [h]:mm rather than h:mm. Bracketed hours keep a twenty-five-hour total visible instead of showing an hour-of-day value after a full day has elapsed. The stored numeric duration and the displayed formatting are separate concepts; changing a format does not restore information lost from a text string.
If A2 contains a numeric duration of 25:30, multiplying by twenty-four gives 25.50 hours. If A2 instead contains the plain text characters 25:30, do not assume the same formula will interpret them as a duration. Convert the source to a valid numeric duration first, or use the calculator on this site to produce the decimal result explicitly.
Sum first, then format or round
For a range of numeric durations, =SUM(A2:A4)*24 produces combined decimal hours. Format that final cell to the desired number of places. Formatting controls what is visible while retaining the underlying numeric value. An explicit ROUND formula changes the value available to later calculations, so use it at the intended final boundary.
Three one-minute numeric durations total 0.05 hours. If each one-minute row is explicitly rounded to two decimal places before summing, the resulting 0.06 differs from the exact source total. This distinction also explains why adding the values you can see on a formatted sheet may differ from a formula that sums their underlying values.
Keep exports and formulas interpretable
Download the worked CSV and open it in your spreadsheet application. It includes numeric day fractions, multiplication formulas, and expected hours for comparison. CSV itself does not preserve cell formats, colors, or workbook settings; set the result columns to Number after opening. Regional spreadsheet settings can change how CSV separators and formulas are interpreted.
The main Batch converter is another option when the source is a list of h:mm strings. Its CSV includes original input, exact minutes, and displayed decimal hours. The displayed column is a formatted result rather than a formula. Keep the original input if you need to recalculate at another precision. For spreadsheet formula background, see the Microsoft Support reference linked above.