Podcast ad slot timestamp calculator

Enter the duration in seconds, choose where the pre-roll, mid-roll, and post-roll should occur from 0 to 100 percent, and receive both numeric offsets and readable timecodes. The calculation is deterministic, so producers, ad operations teams, and publishing systems can use the same placement rules repeatedly without dragging a playhead across every episode or estimating positions by hand.

Convert campaign percentages into edit-ready timestamps

Podcast advertising plans often describe placement as a percentage because a relative position transfers cleanly between episodes of different lengths. A direction such as “place the mid-roll at 50 percent” is easy to standardize, but an editor or publishing system still needs an exact timecode. This calculator multiplies the episode duration by each requested percentage and returns the resulting offset in seconds together with a readable HH:MM:SS.mmm timestamp. Provide the full duration in seconds, then enter one percentage for the pre-roll, mid-roll, and post-roll. For a 3,600-second episode, 2.5 percent becomes 90 seconds, 50 percent becomes 1,800 seconds, and 97.5 percent becomes 3,510 seconds. The named results keep each placement attached to its intended role, reducing the chance that values are copied into the wrong field. Because the same deterministic arithmetic is used every time, the output is suitable for production notes, insertion manifests, approval sheets, and automated workflows that need consistent ad markers across an episode catalog.

Understand precision, boundaries, and validation

Every percentage is measured from the start of the episode. Zero percent therefore resolves to the opening timestamp, while 100 percent resolves to the exact episode duration. Values between those boundaries produce proportional positions, including fractional percentages such as 12.5 or 87.25. Numeric offsets are returned with up to six decimal places, and display timestamps are rounded to the nearest millisecond, which matches the precision commonly used by audio editing and publishing interfaces. The calculator rejects a percentage below 0 or above 100 instead of silently clipping it, because clipping could move an advertisement to a materially different location while making the request appear successful. It also rejects missing, nonnumeric, infinite, or nonpositive durations. These checks make mistakes visible before timestamps reach an insertion workflow. The calculator does not decide whether a chosen location is editorially appropriate, detect speech boundaries, or move a marker away from music or dialogue. It performs the percentage-to-time conversion exactly and leaves content-aware placement decisions to the producer or a separate analysis tool.

Use the results in podcast production workflows

The returned slot list is ordered as pre-roll, mid-roll, and post-roll, with each record containing the original percentage, a numeric second offset, and a formatted timestamp. A producer can paste the readable value into an edit decision list or episode worksheet, while an integration can consume the numeric offset without parsing a timecode string. This dual representation is useful when one team reviews placements visually and another sends structured values to an ad server. For recurring shows, keep the campaign percentages as the stable policy and run each new episode duration through the calculator. That approach preserves the intended relative spacing even when episode lengths vary from week to week. Before publishing, compare the markers with the final mastered file rather than an earlier rough cut, because trimming an intro or adding credits changes the total duration and therefore every proportional timestamp. The API price is $0.002 per request, while the browser implementation uses the same calculation logic. No audio upload is required: only duration and percentage values are processed, so the calculation can fit into lightweight planning and automation steps.