Compute charge flow from current, time, or charge. Choose units and get clean, consistent outputs. Download CSV or PDF reports for quick record keeping.
Charge flow in a circuit relates current and time: Q = I × t, where Q is charge (coulomb), I is current (ampere), and t is time (second).
Rearranging gives I = Q / t and t = Q / I. The electron count estimate uses N = |Q| / e, with e as the elementary charge.
| Current (A) | Time (s) | Charge (C) | Electrons moved (approx.) |
|---|---|---|---|
| 2.0 | 10 | 20 | 1.248e+20 |
| 0.250 | 30 | 7.5 | 4.681e+19 |
| 0.005 | 120 | 0.6 | 3.746e+18 |
These examples assume Q = I × t and electron count N = |Q| / e.
Charge flow describes how much electric charge passes a point in a circuit during a time interval. If you know the current level and how long it flows, you can estimate transferred charge for batteries, capacitors, electrolysis, sensors, and pulse‑driven loads.
Current is defined as charge per second, so multiplying current by time yields total charge. This simple identity supports coulomb counting in power systems, helps validate instrument readings, and provides a quick reality check when comparing duty cycles, bursts, and continuous operation.
Enter values using convenient units such as mA, µA, minutes, hours, mC, or nC. The calculator converts everything to base units internally, which reduces mistakes when mixing milliseconds with hours or microamps with amps. Always confirm the selected unit beside each field.
Choose the unknown you want to compute: charge, current, or time. The tool disables the solved field and uses the other two inputs, so you avoid accidental overwrites. This is useful when you measured a current trace and need charge, or when you have a charge limit and need time.
In addition to coulombs, the calculator estimates the number of electrons transferred using N = |Q|/e, where e is the elementary charge. This perspective is valuable in semiconductor and particle discussions, and it often highlights prefix errors—like confusing mC with C—immediately.
Common applications include estimating charge delivered by a constant‑current source, sizing integration capacitors in analog circuits, checking the charge removed from a battery during standby, and quantifying charge per pulse in actuators or communication hardware. It also helps compare two operating modes on the same charge budget.
Inspect the computed value in more than one unit to confirm magnitude and readability. For example, 0.012 C may be clearer as 12 mC. Use sign conventions consistently: a negative current can represent opposite direction, while the electron count is shown as an absolute quantity for scale.
Use CSV export to log inputs and results for documentation, audits, and quick spreadsheet analysis. The PDF export is ideal for lab notebooks and client deliverables, preserving the same units and rounding shown on screen. Include any assumptions, such as constant current and steady conditions, in your report.
Charge (Q) is the total amount of electricity transferred, measured in coulombs. Current (I) is the rate of charge flow, measured in amperes, where 1 A equals 1 coulomb per second.
It uses Q = I × t for charge, and the rearrangements I = Q/t and t = Q/I. Electron count is estimated with N = |Q|/e using the elementary charge constant.
Yes. A negative sign can represent direction opposite to your chosen reference. The computed charge will follow the same sign. The electron count is shown as an absolute value to indicate magnitude.
You can enter current in A, mA, or µA; time in seconds, milliseconds, minutes, or hours; and charge in C, mC, µC, or nC. Results are also displayed in multiple convenient units.
It assumes current is constant over the interval. If current varies, use an average current or integrate a current‑versus‑time waveform. For pulsed signals, compute per‑pulse charge and multiply by pulse count.
If you measured current and duration, solve for charge. If you have a charge limit and a known current, solve for time. If you know charge transferred over a period, solve for average current.
Even small coulomb values correspond to many electrons because e is very small. Large counts often indicate the result is correct; however, double‑check prefixes and units if the count is unexpectedly extreme.
Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.