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MOSFET Switching Loss Calculator

First-order hard-switching overlap loss P_sw = ½·Vds·Id·(tr+tf)·f_sw, plus optional gate-drive power Qg·Vdrive·f. Not a full MOSFET loss stack. Runs locally in your browser.

Instant result
Result
—

Enter values to calculate.

Inputs—
Mode—
Formula—
Trust summary CVP VERIFIED · CVP protocol 1.0.0-proposed · Engineering assurance
Input interpretation
Enter values to calculate.
Result
—
Assurance
Engineering
Declared partition coverage
PASS · 3/3 declared partitions (overlap-only, with-gate, invalid-domain) · Matrix
Known limitations
  • Hard-switching approximation — soft-switching / Coss / Qrr excluded here
  • Core CVP does not include live graph, viewport, or pointer interaction.
Model
First-order hard-switching overlap loss and optional gate-drive power.
Scope
Linear V/I transition; neglects Coss/Qoss and diode recovery.
Verification
Engine tested · Source checked · v1.0.0 · CVP VERIFIED · CVP protocol 1.0.0-proposed · Engineering assurance· View Manifest · CVP overview · Specification
Versions
Calculation 1.0.0 · CVP protocol 1.0.0-proposed
CVP identity
5/5 property · digest e80c68d19929
Legacy regression
13/13 tests · Production surface contract 11/11
Reference
O1 model · O2 expected_values · O2 numerical_behavior
Interfaces
PASS · UI (SSR) / REST / MCP — ui-ssr is query-result HTML, not a live browser session.
Supplemental domain review
Internal · Pass · electrical-engineer
Named expert review
Not performed
CVP suite
2/2 golden · 6/6 CVP boundary · 6/6 invalid · 5/5 property · 1/1 cross-interface · 11/11 CVP contract · Manifest
Sources
Sources
Evidence
2 legacy golden · 6 legacy boundary · legacy regression suite · 2/2 oracle-backed golden · 6/6 invalid · Artifact integrity PASS · CalculatorX electrical review
This calculator CURRENT · Public schema 1.0.0 matches · Semantic contract ✓ · Production attested · Public/cache ✓ · Origin ✓
Semantic contract
PASS
Full verification

Manifest identity, reference classes, interfaces, suite, and production records.

Formulas

Core equations used by this calculator.

Hard-switching overlap lossP_sw = ½ × Vds × Id × (tr + tf) × f_sw
Gate-drive powerP_gate = Qg × Vdrive × f_sw
iLinear V/I overlap only. Excludes Coss/Qoss and diode recovery. P_gate is drive-circuit power, not necessarily dissipated in the MOSFET die. Datasheet Eon/Eoff methods may differ. Conduction loss is a separate tool.

How to use

1

Enter Vds and Id

Voltage and current being switched.

2

Enter tr, tf, f_sw

Rise/fall times (s) and switching frequency (Hz).

3

Optional Qg and Vdrive

Both required together for gate-drive power.

Example calculations

Common configurations with formula and result.

ϟ

48 V · 10 A · 100 kHz

tr=50 ns · tf=40 ns

P_sw = ½·V·I·(tr+tf)·f
P_sw = 2.16 W
ϟ

With gate-drive power

Qg=50 nC · Vdrive=10 V

P_gate = Qg·V·f
P_gate = 0.05 W · combined switching-related = 2.21 W

MOSFET Switching Loss calculator specification

Version 1.0.0 · Engine tested · Supplemental domain review · Internal · 2026-08-16

Calculation status

Review policy · Evidence · Reviewed by CalculatorX electrical review (electrical-engineer)

Definition
A first-order hard-switching overlap estimate is P_sw = ½ · Vds · Id · (tr + tf) · f_sw. Optional gate-drive power is P_gate = Qg · Vdrive · f_sw. Combined switching-related power ≈ P_sw + P_gate — not MOSFET junction total dissipation.
What it calculates
First-order hard-switching overlap loss and optional gate-drive power.
Inputs
  • Vds > 0 (V), Id > 0 (A)
  • tr > 0 (s), tf > 0 (s), f_sw > 0 (Hz)
  • Optional Qg > 0 (C) and Vdrive > 0 (V) together — Qg at approximately that Vdrive
Outputs
  • P_sw_W (overlap), P_gate_W (drive power), P_total_W (P_sw+P_gate)
  • Echoed Vds, Id, tr, tf, f_sw, Qg, Vdrive
Formula
P_sw=½·Vds·Id·(tr+tf)·f_sw; P_gate=Qg·Vdrive·f_sw; P_total=P_sw+P_gate (switching-related, not die total)
Assumptions
  • Linear V/I transition; neglects Coss/Qoss and diode recovery.
  • tr/tf are effective overlap times at the operating point.
  • P_gate is gate-drive power shared among driver, Rg, and Rg,int — not MOSFET junction dissipation.
  • Qg is total gate charge at approximately the entered Vdrive, not an unscaled datasheet Qg at a different VGS.
Units
  • V, A, s, Hz, C → W
Boundary conditions
  • Missing required → MISSING_REQUIRED_INPUT
  • ≤ 0 → VALUE_MUST_BE_POSITIVE
  • Only one of Qg/Vdrive → NEEDS_TWO_INPUTS
  • Non-finite → INVALID_NUMBER
Example
Vds=48, Id=10, tr=50ns, tf=40ns, f=100kHz → P_sw=2.16 W
Validation cases

4 published on this page · 13/13 tests · Production surface contract 11/11 · View evidence

  • Vds=48, Id=10, tr=50e-9, tf=40e-9, f_sw=1e5 → P_sw_W=2.16
  • + Qg=50e-9, Vdrive=10 → P_gate_W=0.05, P_total_W=2.21
  • missing tr → error MISSING_REQUIRED_INPUT
  • Qg without Vdrive → error NEEDS_TWO_INPUTS
Sources
Last reviewed
2026-08-16
Reviewed by
CalculatorX electrical review (electrical-engineer)
Calculation version
1.0.0

Background

Interpretation and common distinctions.

Estimate hard-switching overlap loss (P_{sw} = \tfrac{1}{2} V_{DS} I_D (t_r+t_f) f_{sw}) and optional gate-drive power. This is a first-order probe — not a full MOSFET loss stack.

Default example: 48 V · 10 A · 50 ns / 40 ns · 100 kHz → P_sw = 2.16 W.

Supported and not supported

Supported

  • Hard-switching overlap loss (first-order linear V/I)
  • Optional gate-drive power when Qg and Vdrive are both given
  • API via electrical.mosfet.switching_loss

Not supported

  • Soft-switching / ZVS / ZCS
  • Eon/Eoff table interpolation or Qoss models
  • Treating P_gate as MOSFET junction dissipation
  • Conduction loss (see MOSFET conduction loss, or MOSFET Total Loss to compose terms)

Agent / API notes

Capability id: electrical.mosfet.switching_loss · tool id: mosfet-switching-loss · pin calculation_version: 1.0.0.

Stable error codes: MISSING_REQUIRED_INPUT, INVALID_NUMBER, VALUE_MUST_BE_POSITIVE, NEEDS_TWO_INPUTS.

Other calculators in this family: ADC Error Budget Calculator, Diode Equation Calculator, LDO Thermal Calculator, LED Resistor Calculator, MOSFET Conduction Loss Calculator, MOSFET Junction Temperature Calculator, MOSFET Threshold & Overdrive Calculator, MOSFET Total Loss Calculator . Explore all Semiconductor.

→ ADC Error Budget Calculator Combine ADC gain, offset, INL, and DNL errors (RSS or worst-case) into total LSB, volts, and %FS. Runs locally in your browser. › → Diode Equation Calculator Shockley diode law I_D=I_S·(e^(V_D/(n·V_T))−1). Solve current or voltage, including reverse branch I_D > −I_S. Runs locally in your browser. › → LDO Thermal Calculator Compute LDO dissipation P=(Vin−Vout)·Iout (+ Iq·Vin) and junction temperature. Runs locally in your browser. › → LED Resistor Calculator Size the series resistor for one or more LEDs: R = (Vs − n·Vf) / If. › → MOSFET Conduction Loss Calculator Calculate MOSFET conduction loss from I, Rds(on), current definition (DC / on-interval RMS / full-cycle RMS), and optional Rds(Tj) via linear α or datasheet ratio. Runs locally in your browser. › → MOSFET Junction Temperature Calculator Estimate MOSFET junction temperature from ambient, dissipation, and thermal resistance (effective RθJA, or case/heatsink-dominant RθJC+RθCA). Optional thermal margin. › → MOSFET Threshold & Overdrive Calculator Calculate MOSFET overdrive Vod=Vgs−Vth, square-law drain current, or model Vth. Vth here is the long-channel square-law parameter — not datasheet VGS(th). Runs locally in your browser. › → MOSFET Total Loss Calculator MOSFET device dissipation from conduction + hard-switching + optional Coss/Eoss, plus optional gate-drive and Qrr commutation. Tj uses P_device, not associated total. Omitted terms are not treated as 0 W. Runs locally in your browser. ›
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Frequently asked questions

Key distinctions behind the calculation.

What is MOSFET switching loss?

Energy dissipated while voltage and current overlap during turn-on/off, averaged over the switching period. The ½·V·I·(tr+tf)·f form is a first-order overlap estimate — not a full MOSFET switching-loss stack (Coss/Qoss, Eon/Eoff, and Qrr are out of scope).

Does this include conduction loss?

No. Use the MOSFET conduction loss calculator, or MOSFET Total Loss to compose both terms.

Is P_gate MOSFET junction dissipation?

No. Gate-drive energy is shared among the driver, external gate resistor, and the MOSFET internal gate resistance. Do not treat P_sw + P_gate as die total loss for Tj = Ta + P·RθJA.

Must I provide Qg?

No. Omit both Qg and Vdrive for overlap-only. Provide both together to add gate-drive power.

Can I use datasheet Qg at 10 V with Vdrive = 6 V?

Not without scaling. Qg depends on gate-drive voltage. Use the Qg specified or estimated at approximately the entered Vdrive.

What if tr is missing?

The API returns MISSING_REQUIRED_INPUT.