# Seconds to Milliseconds (s to ms)

> Convert seconds to milliseconds: 1 s = 1000 ms. Exact conversion factor, formula, 22-row table and worked examples, with JSON API and MCP access.

- Page id: `seconds-to-milliseconds` · Quantity: Time (`time`, base unit s) · Tool: `convert_units`
- Canonical page: https://tttkmbb.com/conversion/seconds-to-milliseconds · This document: https://tttkmbb.com/conversion/seconds-to-milliseconds.md · JSON: https://tttkmbb.com/conversion/seconds-to-milliseconds.json (add `?value=` for a result)

## Formula

- `1 s = 1000 ms`
- `milliseconds = seconds × 1000`
- Reverse: `seconds = milliseconds × 0.001`

The factor follows from the SI definitions of both units (NIST SP 811); values below are rounded to 6 significant figures, the API returns up to 12.

## Worked examples

- 5 s = 5000 ms
- 12.5 s = 12500 ms
- 100 s = 100000 ms

## Conversion table

| Seconds (s) | Milliseconds (ms) |
| --- | --- |
| 1 | 1000 |
| 2 | 2000 |
| 3 | 3000 |
| 4 | 4000 |
| 5 | 5000 |
| 6 | 6000 |
| 7 | 7000 |
| 8 | 8000 |
| 9 | 9000 |
| 10 | 10000 |
| 15 | 15000 |
| 20 | 20000 |
| 25 | 25000 |
| 30 | 30000 |
| 40 | 40000 |
| 50 | 50000 |
| 75 | 75000 |
| 100 | 100000 |
| 200 | 200000 |
| 250 | 250000 |
| 500 | 500000 |
| 1000 | 1000000 |

## API

- `GET https://tttkmbb.com/api/v1/convert?value=5&from_unit=s&to_unit=ms` → unified JSON envelope with `result.values.result`, `formula`, `factor`, `sources`, `freshness`
- MCP: server `https://tttkmbb.com/mcp`, tool `convert_units` with `{"value":5,"from_unit":"s","to_unit":"ms"}`
- All time units: https://tttkmbb.com/api/v1/units?quantity=time · full converter: [Time Converter](https://tttkmbb.com/conversion/time.md)
- Authentication: none. Freshness: `static` (fixed conversion factors).

## FAQ

**How many milliseconds are in one second?**

1 s = 1000 ms. The factor comes from the SI definitions of both units (NIST SP 811 / BIPM), so it is exact or correct to at least 10 significant figures.

**What is the formula to convert seconds to milliseconds?**

Multiply the value in seconds by 1000: milliseconds = seconds × 1000. For example, 5 s = 5000 ms.

**How do I convert milliseconds back to seconds?**

Multiply by the inverse factor 0.001 (seconds = milliseconds × 0.001), or use the milliseconds-to-seconds page.

## Related conversions

- [Milliseconds to seconds](https://tttkmbb.com/conversion/milliseconds-to-seconds.md) (reverse)
- [Hours to Minutes](https://tttkmbb.com/conversion/hours-to-minutes.md)
- [Minutes to Hours](https://tttkmbb.com/conversion/minutes-to-hours.md)
- [Minutes to Seconds](https://tttkmbb.com/conversion/minutes-to-seconds.md)
- [Seconds to Minutes](https://tttkmbb.com/conversion/seconds-to-minutes.md)
- [Days to Hours](https://tttkmbb.com/conversion/days-to-hours.md)
- [Hours to Days](https://tttkmbb.com/conversion/hours-to-days.md)
- [Weeks to Days](https://tttkmbb.com/conversion/weeks-to-days.md)
- [Days to Weeks](https://tttkmbb.com/conversion/days-to-weeks.md)

## Data Sources

- NIST Special Publication 811 – Guide for the Use of the International System of Units (SI), Appendix B conversion factors — https://www.nist.gov/pml/special-publication-811 (standard, retrieved 2026-09-24)
- BIPM – The International System of Units (SI Brochure, 9th edition) — https://www.bipm.org/en/publications/si-brochure (standard, retrieved 2026-09-24)
- Wikipedia – Conversion of units — https://en.wikipedia.org/wiki/Conversion_of_units (reference, retrieved 2026-09-24)