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Buck Converter Ripple Calculator

Assumed-CCM buck peak-to-peak inductor ripple ΔI_L,pp = Vout(1−D)/(f L) and optional capacitor-only ΔV_C,pp ≈ ΔI/(8fC). 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 (ccm-with-c, ccm-without-c, invalid-domain) · Matrix
Known limitations
  • Ideal CCM assumed, not measured. No Iout, so CCM/DCM is not certified. ESR, DCM, and current-mode dynamics are out of scope.
  • Core CVP does not include live graph, viewport, or pointer interaction.
Model
Assumed-CCM peak-to-peak inductor ripple and optional capacitor-only ΔV_C.
Scope
Ideal CCM assumed, not measured
Verification
Engine tested · Source checked · v1.1.0 · CVP VERIFIED · CVP protocol 1.0.0-proposed · Engineering assurance· View Manifest · CVP overview · Specification
Versions
Calculation 1.1.0 · CVP protocol 1.0.0-proposed · Evidence 2026-09-11.ptp-ccm-c-optional
Verification revision
2026-09-11.ptp-ccm-c-optional · 4/4 property · digest 332ecf117919
Legacy regression
15/15 tests · Production surface contract 4/4
Trust layers
Verification VERIFIED · Production CURRENT · overall VERIFIED
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 · 12/12 CVP boundary · 15/15 invalid · 4/4 property · 4/4 metamorphic · 2/2 cross-interface · 4/4 CVP contract · Manifest
Sources
Sources
Evidence
1 legacy golden · 10 legacy boundary · legacy regression suite · 2/2 oracle-backed golden · 15/15 invalid · Artifact integrity PASS · CalculatorX electrical review
This calculator CURRENT · Public schema 1.1.0 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.

Inductor ripple (peak-to-peak)ΔI_L,pp = Vout·(1−D)/(f_SW·L)
Capacitor ripple (peak-to-peak, ESR=0)ΔV_C,pp ≈ ΔI_L,pp/(8·f_SW·Cout)
CCM boundary currentI_out,crit = ΔI_L,pp/2
iContinuous conduction is assumed, not measured. Ideal switch/diode. ΔV_C neglects ESR and is not total output ripple.

How to use

1

Enter Vin, Vout, switching frequency, and inductance

All must be greater than zero, with Vout < Vin. Duty is taken as Vout/Vin for the ideal CCM model.

2

Optional: enter output capacitance Cout

If Cout is provided, capacitor voltage ripple is estimated with ESR = 0. Leave it blank to report inductor ripple only.

3

Read peak-to-peak inductor current and the CCM boundary

ΔI_L,pp is peak-to-peak, not RMS or ±amplitude. Ideal CCM requires load current above ΔI_L,pp/2.

Example calculations

Common configurations with formula and result.

ϟ

12 V → 5 V, 100 kHz, 10 µH, 100 µF

Assumed CCM · ESR = 0

ΔI_L,pp = Vout(1−D)/(f L)
D = 41.67% · ΔI_L,pp = 2.9167 A · ΔV_C,pp = 36.46 mV · CCM boundary ≈ 1.458 A

Buck Converter Ripple calculator specification

Version 1.1.0 · Engine tested · Supplemental domain review · Internal · 2026-09-11

Calculation status

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

Definition
Ideal CCM duty is D = Vout/Vin. Peak-to-peak inductor ripple is ΔI_L,pp = Vout·(1−D)/(f_SW·L). Optional capacitor-only output ripple (ESR=0) is ΔV_C,pp ≈ ΔI_L,pp/(8·f_SW·Cout).
What it calculates
Assumed-CCM peak-to-peak inductor ripple and optional capacitor-only ΔV_C.
Inputs
  • Vin_V
  • Vout_V
  • f_Hz
  • L_H
  • C_F?
Outputs
  • D
  • dI_L_A (pp)
  • I_ccm_boundary_A
  • dV_out_V? (pp, ESR=0)
  • dV_over_Vout?
Formula
ΔI_L,pp=Vout(1−D)/(f L)
Assumptions
  • Ideal CCM assumed, not measured
  • ΔI and ΔV are peak-to-peak
  • ESR=0 for ΔV_C
Units
  • V, Hz, H, F → A, V (peak-to-peak)
Boundary conditions
  • Vout≥Vin → VALUE_OUT_OF_RANGE
  • Vin, Vout, f, L ≤0 → VALUE_MUST_BE_POSITIVE
  • C=0 if present → VALUE_MUST_BE_POSITIVE
Example
12 V→5 V, 100 kHz, 10 µH, 100 µF → ΔI_L,pp=2.9167 A, ΔV_C,pp=36.46 mV
Validation cases

2 published on this page · 15/15 tests · Production surface contract 4/4 · View evidence

  • Vin=12 Vout=5 f=1e5 L=1e-5 C=1e-4 → dI_L,pp=2.9167 A, ΔV_C,pp=36.46 mV
  • Vin=12 Vout=5 f=1e5 L=1e-5 C omitted → dI_L,pp=2.9167 A, dV absent
Sources
Last reviewed
2026-09-11
Reviewed by
CalculatorX electrical review (electrical-engineer)
Calculation version
1.1.0

Background

Interpretation and common distinctions.

Estimate buck converter peak-to-peak ripple under an ideal CCM model.

What ΔI and ΔV mean

The inductor current waveform in CCM is a triangle. ΔI_L,pp is the full peak-to-peak excursion, not RMS ripple and not ±amplitude. Analog Devices writes the same quantity as ΔI_P-P.

ΔV_C,pp is the capacitor-voltage triangle that follows from that current when ESR is neglected:

ΔV_C,pp ≈ ΔI_L,pp / (8 f_SW Cout)

That is not the converter’s total output ripple. A usual engineering estimate is

ΔV_out,pp ≈ ΔI_L,pp · (ESR + 1/(8 f_SW Cout))

How do I know whether the converter is in CCM?

This calculator does not take load current, so it cannot certify CCM. It assumes CCM.

The CCM boundary is I_out,crit = ΔI_L,pp / 2. For the 12 V → 5 V, 100 kHz, 10 µH example, that is about 1.458 A. If Iout falls below that value, the ideal CCM formulas on this page no longer apply.

How switching frequency and inductance affect ripple

Doubling f_SW halves ΔI_L,pp and cuts ΔV_C,pp by four (ΔI already halved, then another 1/f). Doubling L halves ΔI_L,pp. Doubling Cout halves ΔV_C,pp only.

A common inductor first-cut is ΔI_L,pp ≈ 20%–40% of Iout(max) (TI SLVA477B).

Supported and not supported

Supported — Assumed-CCM peak-to-peak ΔI_L and optional capacitor-only ΔV_C · API electrical.buck.ripple

Not supported — DCM, ESR, measured CCM/DCM detection, current-mode control dynamics

Agent / API notes

Capability id: electrical.buck.ripple · tool id: buck-ripple · pin 1.1.0.

dI_L_A is peak-to-peak inductor current (A). dV_out_V is peak-to-peak capacitor voltage with ESR=0 (V) and is omitted when C_F is omitted. I_ccm_boundary_A is ΔI_L,pp/2. assumption is always "ccm" — not a measured operating mode.

Other calculators in this family: AC to DC Rectifier Calculator, Heatsink Thermal Resistance Calculator — θJC, θCS, θSA & Junction Temperature, MOSFET Switching Loss Calculator, MOSFET Total Loss Calculator, Rectifier Ripple Capacitor Calculator . Explore all Power Electronics.

→ AC to DC Rectifier Calculator Ideal half-wave/full-wave rectified waveform — peak, average and RMS voltage, with optional capacitor ripple estimation. Runs locally in your browser. › → Heatsink Thermal Resistance Calculator — θJC, θCS, θSA & Junction Temperature Size required heatsink θSA from Tj,max, or compute junction temperature from effective θJA or the θJC+θCS+θSA stack. Device dissipation only. Runs locally in your browser. › → 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. › → 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. › → Rectifier Ripple Capacitor Calculator Size filter capacitance or estimate ripple for half/full-wave rectifiers: Vripple ≈ I/(f·C). Runs locally in your browser. ›
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Frequently asked questions

Key distinctions behind the calculation.

Are ΔI and ΔV peak-to-peak, RMS, or amplitude?

Peak-to-peak. dI_L_A is ΔI_L,pp and dV_out_V is ΔV_C,pp. They are not RMS ripple, not one-sided peak, and not ±amplitude.

Does MODE CCM mean the converter is in CCM?

No. This calculator assumes ideal CCM. It does not take load current, so it cannot certify CCM vs DCM. Use the reported CCM boundary current: Iout must stay above ΔI_L,pp/2.

Is ΔV the real output ripple?

No. ΔV_C,pp is capacitor-only with ESR neglected. Real output ripple is typically ΔI_L·(ESR + 1/(8fC)) plus switching transients.

What inductor ripple ratio should I target?

A common first-cut is ΔI_L,pp ≈ 20%–40% of Iout(max). This page reports ΔI_L,pp and the CCM boundary; it does not choose L for you.

What if Vout ≥ Vin?

A buck requires Vout < Vin; the API returns VALUE_OUT_OF_RANGE.