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Seconds to Femtoseconds Converter

Enter the time in seconds below to convert it to femtoseconds.

Convert Seconds to Femtoseconds

Enter a value in seconds (s) to convert to femtoseconds (fs).

Result
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5e+15femtoseconds
5 s = 5e+15 fs
Result updates automatically
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Reference:NIST OWM (SI Units — Time)
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Second to Femtosecond Conversion Table

Table showing various second measurements converted to femtoseconds. Click any preset value or arrow to load it into the converter.

How to Convert Seconds to Femtoseconds

To convert seconds to femtoseconds, multiply the time by the following conversion ratio: 1e+15 femtoseconds/second.

Since one second is equal to 1e+15 femtoseconds, you can use this simple formula to convert:

femtoseconds = seconds × 1e+15

The time in femtoseconds is equal to the time in seconds multiplied by 1e+15.

For example, here's how to convert 5 seconds to femtoseconds using the formula above.

femtoseconds = (5 s × 1e+15) = 5e+15 fs

How Many Femtoseconds Are in a Second?

There are 1e+15 femtoseconds in a second, which is why we use this value in the formula above.

1 s = 1e+15 fs|1 fs = 1e-15 s

Our second to femtosecond calculator automatically converts your time measurements with full decimal and scientific precision across US customary, imperial, and SI metric standards.

Seconds and femtoseconds are both units used to measure time. Keep reading to learn more about each unit.

What Is a Second?

Base SI unit of time. It serves as a primary reference unit for measuring time across scientific and practical applications. [1]

The second is classified as an International System of Units (SI) unit of time. Seconds can be abbreviated as s; for example, 1 second can be written as 1 s.

As the primary coherent reference unit for time in this category, all other time units are mathematically anchored to the second (s).

In practice, seconds (s) are widely used across standard time applications within International System of Units (SI) workflows, engineering documentation, and technical data sheets.

What Is a Femtosecond?

A femtosecond is a unit of time equal to 1e-15 seconds (s), the base unit for time. One-quadrillionth of a second (10⁻¹⁵ s), used in ultrafast laser physics. [2]

The femtosecond is classified as a metric and SI-compatible unit of time. Femtoseconds can be abbreviated as fs; for example, 1 femtosecond can be written as 1 fs.

In the metric system, "femto" is the standard SI prefix for quadrillionths, or 10⁻¹⁵. This makes the femtosecond (fs) a convenient decimal multiple of the second (s).

In practice, femtoseconds (fs) are widely used across fine-tolerance laboratory, analytical, and micro-scale time measurements within SI metric workflows, engineering documentation, and technical data sheets.

When converting time between seconds (s) and femtoseconds (fs), keep full floating-point precision (1 s = 1e+15 fs; 1 fs = 1e-15 s) during intermediate calculations and round only the final femtosecond figure to match your instrument tolerance.

More Second & Femtosecond Conversions

Need to calculate in the opposite direction? Use our femtoseconds to seconds calculator to switch your starting unit immediately. You can also explore related tools such as converting femtoseconds to seconds, converting seconds to minutes, or converting seconds to milliseconds.

Frequently Asked Questions

There are 1.000000e+15 femtoseconds (fs) in 1 second (s). Conversely, 1 femtosecond (fs) is equal to 1.000000e-15 seconds (s).

References

NIST · BIPM · ISO
  1. [1]
    NIST OWM (SI Units — Time)·Time Metrology Standard — Seconds (s) to Femtoseconds (fs)
    NIST OWM Standard
  2. [2]
    BIPM (SI Base Unit: Second (s))·Unit Specifications: Second (s) & Femtosecond (fs)
    BIPM Specification
  3. [3]
    NIST CUU (Non-SI Units Accepted for Use (min, h, d))·Conversion Factors & Mathematical Basis (s to fs)
    NIST CUU Reference
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