Calculate time estimate for system in electrical engineering.
SystemOpen
RC Time Constant Calculator
Quick answer
If resistance is 46 Ω and capacitance is 0.00001 F, the time constant is 0.00046 s.
Enter your values
0 Ω10,000 Ω
Ω
F
Time constant
0.00046s
The time constant — roughly how long it takes the circuit to settle to about 63% of its final value.
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See how the result changes
Each table re-runs this calculator with one value changed and everything else left as it is.
Time constant by resistance
If resistance goes from 46 Ω to 69 Ω, time constant changes from 0.00046 s to 0.00069 s (+50%).
| Resistance | Time constant |
|---|---|
| 23 Ω | 0.00023 s |
| 34.5 Ω | 0.000345 s |
| 46 Ωstart | 0.00046 s |
| 69 Ω | 0.00069 s |
| 92 Ω | 0.00092 s |
Time constant by capacitance
If capacitance goes from 0.00001 F to 0.000015 F, time constant changes from 0.00046 s to 0.00069 s (+50%).
| Capacitance | Time constant |
|---|---|
| 0.000005 F | 0.00023 s |
| 0.000008 F | 0.000345 s |
| 0.00001 Fstart | 0.00046 s |
| 0.000015 F | 0.00069 s |
| 0.00002 F | 0.00092 s |
ELECTRICAL & ENGINEERING GUIDE
A quick guide to RC Time Constant
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How to Use the RC Time Constant Calculator
1
Enter Resistance
Provide your resistance, in Ω.
2
Enter Capacitance
Provide your capacitance, in F.
3
View Your Results
Get your time constant instantly, calculated on our server.
What is RC Time Constant?
This electrical & engineering tool works out your time constant instantly, so you don't have to do the math by hand.
“One quick calculation, so you always know your time constant before you decide.”
What Affects Your Time constant
Your time constant depends on the values below.
Resistance
Changing your resistance changes your time constant.
Capacitance
Changing your capacitance changes your time constant.
Example Result
Here's what you can expect from a RC time constant calculation:
- Resistance
- 46 Ω
- Capacitance
- 0.00001 F
- Time constant
- 0.00046 s
Frequently Asked Questions
- How does resistance affect time constant?
- If resistance goes from 46 Ω to 69 Ω, time constant changes from 0.00046 s to 0.00069 s (+50%).
- How does capacitance affect time constant?
- If capacitance goes from 0.00001 F to 0.000015 F, time constant changes from 0.00046 s to 0.00069 s (+50%).
- How to calculate RC time constant?
- Fill in resistance and capacitance in the RC Time Constant Calculator above and your time constant is calculated instantly. Change any value to see how the result responds.
- What does an example RC time constant calculation look like?
- If resistance is 46 Ω and capacitance is 0.00001 F, the time constant is 0.00046 s.
- Is this calculator free to use?
- Yes — every calculator on this site is completely free, with no sign-up or account required.
- How accurate is this calculator?
- It uses the standard formula and calculates on our server for every request, so results are precise for the values you enter.
- Is my data saved anywhere?
- No. Nothing you enter is stored or sent anywhere unless you choose to share a link with your values included.
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