Your result
Click Calculate
Enter your values, then click Calculate result.How this calculator helps
This timecode calculator adds or subtracts two duration labels at a selected integer frame rate. Enter each value as HH:MM:SS:FF using colons, then choose 24, 25, 30, 50 or 60 frames per second. It converts both inputs to frame counts before performing arithmetic and formats the signed result back into timecode. The scope is intentionally explicit: fractional rates, drop-frame labels and media-file inspection are not implemented. Use the worksheet for matching integer-rate non-drop-frame durations rather than assuming every timecode label is a wall-clock timestamp or a interchangeable frame-rate format.
How to use it
- 1
Verify the project uses a supported exact integer NDF rate, then enter both durations as two-digit HH:MM:SS:FF labels.
- 2
Enter the values in the displayed units and verify the source record or measurement basis.
- 3
Click Calculate result to submit the current inputs.
- 4
Read the labeled outputs with the methodology and checks. Input edits retain the previous result until Calculate is clicked again.
Formula and methodology
Frame count = ((hours × 60 + minutes) × 60 + seconds) × fps + frame field. Add or subtract counts, then divide by integer fps for seconds and reconstruct HH:MM:SS:FF from the absolute count.
The calculator applies the displayed arithmetic to the values entered on this device. It does not silently load a local tax rate, currency conversion or commercial assumption.
Worked calculation example
At 30 fps NDF, 00:00:12:15 represents 375 frames. Adding 00:00:00:15 gives 390 frames, or 00:00:13:00. Subtracting a larger count gives a signed negative duration rather than an automatic midnight rollover.
How to interpret your result
At 30 fps NDF, 00:00:12:15 represents 375 frames. Adding 00:00:00:15 gives 390 frames, or 00:00:13:00. Subtracting a larger count gives a signed negative duration rather than an automatic midnight rollover. Exact integer-rate NDF durations only. No fractional or drop-frame conversion, midnight dates, media inspection, frame resampling, synchronization or inclusive-endpoint adjustment. Compare the main quantity with the separately labeled intermediate values before using it in another worksheet. Retain units, input basis and any selected convention with the result so it can be reproduced.
For different inputs or formulas, use Decimal Time Converter; Time Between Calculator; Swim Time Converter.
Related questions this calculator covers
- timecode calculator
Scenario comparison
| Scenario | What it shows |
|---|---|
| 30 fps: 00:00:12:15 | 375 frames. |
| Add 00:00:00:15 | 390 frames and 00:00:13:00. |
| First smaller than second | a signed negative duration. |
Common mistakes to avoid
- Treating the frame field as hundredths of a second.
- Using fractional-rate media in an integer-rate option.
- Assuming signed duration subtraction handles midnight dates.
Convert each label to an integer frame count and perform the operation there. Confirm seconds equal signed frames divided by the selected rate. Test one frame below a second boundary and one frame above it. Reconcile any inclusive endpoint convention in your editor independently.
Authoritative reference. Methodology reference reviewed on 4 October 2026. SolvePilot applies the explicitly displayed arithmetic and its own bounded input handling; the linked documentation does not certify an individual result. Review by Mohammad Qasim is editorial and technical, not a specialist assessment of the entered situation.What can affect the result?
The final field is frames, not decimal seconds
At thirty fps, a frame field of fifteen represents one-half second. At twenty-four fps, the same field represents fifteen twenty-fourths of a second. Therefore a label cannot be interpreted correctly without its frame rate. The tool rejects a frame field equal to or greater than the selected rate. Use two digits in every input field, including leading zeros, so a malformed duration does not silently become a different frame count.
Only matching integer-rate non-drop-frame durations are supported
The selector lists exact integer rates. It does not interpret 29.97, 23.976 or 59.94 as their rounded nominal labels, and it rejects semicolon drop-frame notation. Fractional-rate media has a distinction between nominal timecode labels and elapsed seconds that requires another model. Do not force such material into the thirty-fps option merely because its label looks similar. Check project and source settings in the editing system before using this calculation.
Add frames before formatting the result
Frame-based arithmetic handles carries between the final field, seconds, minutes and hours consistently. Adding fifteen frames to a label already ending in fifteen at thirty fps creates one full second. A decimal calculator cannot achieve that by adding the visible colon-separated fields independently. The output frame count is an independent check for a duration sum. Keep the integer count when moving the result between systems that can directly accept frame offsets.
Signed subtraction differs from midnight wrapping
Subtracting the second input from the first produces a negative duration when the second is larger. The page shows a minus sign and the absolute timecode magnitude. It does not assume the values are time-of-day stamps spanning midnight. Inputs are limited to hours zero through twenty-three, but an addition may legitimately display more than twenty-three output hours because duration sums do not wrap. Resolve chronological dates separately if your task concerns real recording timestamps.
Confirm endpoint and edit conventions outside the tool
Some editing tasks count an inclusive final frame, while others calculate the difference between boundary positions. The worksheet adds or subtracts the supplied frame counts without inserting an extra endpoint frame. If a clip length differs by one frame, inspect the editor’s in/out convention before changing arithmetic. This page neither reads media headers nor verifies synchronization, audio sample alignment or a timecode track. A correctly formatted result can still be inappropriate for a mismatched project setting.
Privacy and browser processing
Values entered on this page are processed in the current browser session. SolvePilot does not require an account and does not receive the values entered into the calculator. Refreshing or closing the page clears the working values unless the browser itself restores a previous session. Avoid entering identifying or account information because the calculation needs summary values only.
Accuracy and verification
Accuracy depends first on input quality. Confirm definitions, scales, dates and source information before entering a value. Keep an independent record of any result used for planning because this page does not create an official statement or retain a calculation history.
Limits of this estimate
Exact integer-rate NDF durations only. No fractional or drop-frame conversion, midnight dates, media inspection, frame resampling, synchronization or inclusive-endpoint adjustment. Results use the entered assumptions and do not verify their real-world applicability. Calculator inputs are processed locally by the browser interface. Avoid entering identifying records; save only the quantities and context necessary for your own review.
Sources and review information
Frequently asked questions
Does this support drop-frame timecode?＋
No. Only the listed exact integer-rate NDF options are supported. Semicolon labels and fractional rates need a separate model.
Can FF equal the frame rate?＋
No. Frame fields run from zero through fps minus one. At thirty fps the largest input frame field is 29.
Does subtraction wrap across midnight?＋
No. It returns a signed duration. Chronological date handling is outside the tool.
Can a sum exceed 24 hours?＋
Yes. The output is a duration, so addition does not reset after twenty-four hours.
Does this inspect a video file?＋
No. You supply the labels and verified frame rate. No media track is read or synchronized.