Second to Planck Time Converter
Quickly convert from Second to Planck Time.
How to convert
Formula:
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At the quantum and atomic scale, the second is far too coarse to capture the fastest physical processes.
Where is it used?
• Ultrafast Laser Physics and Chemistry — Femtosecond lasers (pulse duration 10–100 fs) are used in time-resolved spectroscopy to observe chemical bond formation and breaking in real time; Ahmed Zewail's femtochemistry...
Examples:
• 1 Planck time (tP) = 5.391 × 10⁻⁴⁴ s
• 1 atomic unit of time (ℏ/Eₕ) = 2.41888 × 10⁻¹⁷ s (24.19 as)
At the quantum and atomic scale, the second is far too coarse to capture the fastest physical processes. Ultrafast science uses femtoseconds (10⁻¹⁵ s) to study chemical bond breaking and forming; attoseconds (10⁻¹⁸ s) to track electron motion in atoms — a field awarded the 2023 Nobel Prize in Physics; and zeptoseconds (10⁻²¹ s) to time the passage of a photon across a hydrogen molecule. The Planck time (~5.39 × 10⁻⁴⁴ s) is the theoretical lower boundary of meaningful time intervals in current physics. The atomic unit of time (~24.2 as) is the natural time scale of electron dynamics in hydrogen.
Quantum time units span many orders of magnitude below the second: the Planck time tP = √(ℏG/c⁵) ≈ 5.391 × 10⁻⁴⁴ s (the time for light to cross the Planck length); the atomic unit of time ℏ/Eₕ = 24.1888 attoseconds (Eₕ = Hartree energy); the zeptosecond (10⁻²¹ s, shortest measured time interval as of 2023); the attosecond (10⁻¹⁸ s, electron orbital periods); the femtosecond (10⁻¹⁵ s, molecular vibrations and nuclear motion); and the picosecond (10⁻¹² s, used in ultrafast optics and telecommunications).
Where is it used?
- Ultrafast Laser Physics and Chemistry — Femtosecond lasers (pulse duration 10–100 fs) are used in time-resolved spectroscopy to observe chemical bond formation and breaking in real time; Ahmed Zewail's femtochemistry won the 1999 Nobel Prize in Chemistry.
- Attosecond Science — Attosecond pulse trains from high-harmonic generation allow direct observation of electron dynamics: ionisation, tunnelling, and orbital reconstruction occur on 10–1,000 as timescales; Pierre Agostini, Ferenc Krausz, and Anne L'Huillier shared the 2023 Nobel Prize in Physics for attosecond pulse generation.
- Telecommunications and Signal Processing — Optical fibre data transmission uses pulse widths of picoseconds; jitter in high-speed digital signals is measured in picoseconds; laser pulse timing in LIDAR systems achieves picosecond resolution.
- Nuclear and Particle Physics — Excited nuclear states (isomers) decay on nanosecond to femtosecond timescales; particle physics experiments at CERN measure event timing with picosecond-resolution detectors; muon lifetime (~2.2 μs) and pion lifetime (~26 ns) are fundamental measurements.
Common Conversion Mistakes
Misremembering the femto- and atto- prefix order
The SI prefix sequence below nanosecond (10⁻⁹ s) is: pico (10⁻¹²), femto (10⁻¹⁵), atto (10⁻¹⁸), zepto (10⁻²¹), yocto (10⁻²⁴). Femtosecond is larger than attosecond by a factor of 1,000 — a femtosecond laser pulse of 50 fs = 50,000 as. Confusing the two leads to factor-of-1,000 errors when interpreting ultrafast spectroscopy results.
Assuming the Planck time is measurable
The Planck time (~5.39 × 10⁻⁴⁴ s) is theoretically derived from fundamental constants and represents the timescale at which quantum gravity would be important. It is roughly 10²³ times smaller than the shortest experimentally measured time interval (a zeptosecond, ~10⁻²¹ s). Current technology cannot probe Planck-scale time, and it remains a theoretical construct rather than a measured quantity.
Conflating the atomic unit of time with atomic clock precision
The atomic unit of time (ℏ/Eₕ ≈ 24.19 attoseconds) is a theoretical unit used in quantum chemistry calculations — it is the natural unit of electron dynamics in hydrogen, not related to atomic clock operation. Atomic clocks achieve precision of ~10⁻¹⁸ s (one attosecond) in frequency stability, but this is an engineering achievement in the caesium or strontium standard, not a use of the quantum mechanical atomic time unit.
Quick Reference Table
| From | To |
|---|---|
| 1 Planck time (tP) | 5.391 × 10⁻⁴⁴ s |
| 1 atomic unit of time (ℏ/Eₕ) | 2.41888 × 10⁻¹⁷ s (24.19 as) |
| 1 zeptosecond (zs) | 1 × 10⁻²¹ s (0.001 as) |
| 1 attosecond (as) | 1 × 10⁻¹⁸ s (0.001 fs) |
| 1 femtosecond (fs) | 1 × 10⁻¹⁵ s (1,000 as) |
| 1 picosecond (ps) | 1 × 10⁻¹² s (1,000 fs) |
| Electron orbital period (hydrogen ground state) | ~152 attoseconds |
Frequently Asked Questions
What is a femtosecond and what happens on that timescale?
A femtosecond (fs) = 10⁻¹⁵ s — one quadrillionth of a second. Light travels 0.3 μm (300 nm) in 1 fs — about the width of a typical virus. On femtosecond timescales: molecular bonds vibrate (O–H stretch period ~10 fs); chemical reactions occur (bond breaking in photodissociation: ~100 fs); ultrafast lasers emit pulses as short as 5 fs. Femtosecond lasers enable materials processing with negligible heat-affected zones and are used in laser eye surgery (LASIK flap cutting, ~10⁻¹³ s pulses).
What is an attosecond and why did it win a Nobel Prize?
An attosecond (as) = 10⁻¹⁸ s — one quintillionth of a second. The electron orbital period in hydrogen is ~152 as; ionisation and electron tunnelling occur on 1–1,000 as timescales. In 2001, attosecond X-ray pulses were first generated using high-harmonic generation from femtosecond laser pulses. By 2023, this had matured into a field enabling direct 'movies' of electron motion, awarded the Nobel Prize in Physics to Pierre Agostini, Ferenc Krausz, and Anne L'Huillier.
What is the shortest time interval ever measured?
As of 2023, the shortest measured time interval is approximately 247 zeptoseconds (247 × 10⁻²¹ s ≈ 2.47 × 10⁻¹⁹ s), measured by researchers at Goethe University Frankfurt in 2020. They timed the passage of a photon across a hydrogen molecule (H₂, bond length ~74 pm) using the COLTRIMS reaction microscope. The photon traverses the molecule in ~247 zs, observable via quantum interference in the two-centre photoionisation process.
What is the Planck time and what does it represent?
The Planck time tP = √(ℏG/c⁵) ≈ 5.391 × 10⁻⁴⁴ s is the time for light to travel one Planck length (~1.616 × 10⁻³⁵ m). Below this timescale, the concepts of 'time' and 'causality' as described by current physics theories (general relativity and quantum field theory) are expected to break down — a unified theory of quantum gravity would be needed. It is ~10²³ times shorter than the shortest measured time interval, and no experiment can probe it directly.
Sources & Standards
- CODATA 2018 Recommended Values of the Fundamental Physical Constants (NIST)
- Hentschel, M. et al. — 'Attosecond metrology', Nature 414, 509–513 (2001)
- Grundmann, S. et al. — 'Zeptosecond birth time delay in molecular photoionization', Science 370, 339–341 (2020)
- Nobel Prize in Physics 2023 Press Release — The Royal Swedish Academy of Sciences (attosecond pulses)
Reviewed by The Unit Hub Editorial Team · March 2026