Convert Time to Seconds

Seven: (1) Colon-separated HH:MM:SS, HH:MM, or D:HH:MM:SS. (2) Bare number = hours. (3) ISO 8601 duration PnDTnHnMnS (case-insensitive). (4) Compact with unit suffixes: 1d 2h 3m 4s. (5) Word form: "1 hour, 30 minutes" with commas optional. (6) Decimal-with-unit: 8.5h, 1500ms. (7) Plain decimal seconds (no unit) – passes through unchanged. Mix formats in batch mode; each line parsed independently.

Rejected with the specific error “Negative duration not allowed – use absolute value or Swap to reverse”. This is intentional. Many time-to-seconds tools silently call Math.abs() so -3600 becomes 3600 with no warning. That hides bugs. This tool surfaces the issue instead – if your data has unexpected negatives, you’ll see it immediately.

Yes. 8.5h → 30,600 seconds. 1.25h → 4500 seconds. 0.5d → 43,200 seconds. The parser recognizes decimals before any unit suffix (d/h/m/s/ms). Useful for payroll-style time tracking where times are stored as decimal hours.

The standard interchange format for durations: P[nD][T[nH][nM][nS]]. So P1DT2H3M4S = 1 day, 2 hours, 3 minutes, 4 seconds = 93,784 seconds. APIs (OpenAPI, JSON Schema, GraphQL) and databases (PostgreSQL interval) use this format. The parser is case-insensitive and accepts decimal values in any field (PT1.5H = 5400 seconds).

Yes. Decimal seconds in any input format propagate through. 3661.5 → 3661.5 seconds → reverse-encodes as 01:01:01.500 in HH:MM:SS, 1h 1m 1.5s in compact, PT1H1M1.5S in ISO. The output stays consistent with the input precision.

Multiple lines or comma/semicolon-separated entries become one row each in the output TSV. Each line is parsed independently – one bad line gets an ERROR row but doesn’t fail the rest. Stats show ok vs error counts, sum (total seconds across all valid rows), mean, min, max. Useful for time-tracking spreadsheets where you have a column of durations and want a total in seconds.

Yes. 1 hour 30 minutes, 1h 30m, 1 hr 30 min all give 5400. The parser uses a regex matching digits followed by a unit word (with or without space). Commas and “and” are tolerated as separators: 1 hour, and 30 minutes works too. Unit-less numbers in word form context are skipped (not treated as seconds).

That sibling tool starts with seconds and produces multiple time formats. This one starts with time formats and produces seconds (plus a few extra formats). Same parser/serializer under the hood – just the default direction differs. Swap on either tool flips them to be functionally equivalent. Two URLs because “time to seconds” and “seconds to time” are both common search queries.

No. All parsing, math, and TSV emission run in your browser. Open DevTools → Network and confirm zero requests fire – even when you Convert or Download. Safe for time-tracking spreadsheets, video metadata, or log timestamps you’d rather not send to a third-party converter.

Yes. Total bundle is about 18 KB. Load once, disconnect, keep using. Pure JavaScript arithmetic – no fonts to fetch, no analytics, no remote API. Useful for time math on planes, in airgapped dev environments, or anywhere a cloud-based converter wouldn’t reach.