Skip to content
Specap, Inc.
Specap Inc.The Capacitor Experts
Engineering Intelligence Suite

Precision
Calculators

Professional-grade tools for capacitor design. Calculate energy storage, convert units, and optimize circuit configurations—all free, no signup required.

Instant Results

Real-time calculations

No Signup

Free, no registration

Engineer Approved

Trusted by 100K+ engineers

Formula Reference

Essential equations for capacitor circuit design.

Energy StorageJoules
E = ½CV²
ChargeCoulombs
Q = CV
SeriesFarads
1/C = Σ(1/Cₙ)
ParallelFarads
C = ΣCₙ
Time ConstantSeconds
τ = RC
ReactanceOhms
Xc = 1/(2πfC)

Frequently Asked Questions

How do I calculate energy stored in a capacitor?

Use the formula E = ½CV², where E is energy in Joules, C is capacitance in Farads, and V is voltage in Volts. For example, a 1000µF capacitor charged to 50V stores E = ½ × 0.001 × 50² = 1.25 Joules.

How do I convert between pF, nF, and µF?

1 µF = 1,000 nF = 1,000,000 pF. To convert: divide by 1000 to go up (pF→nF→µF), multiply by 1000 to go down (µF→nF→pF). Our calculator handles all conversions automatically.

How do capacitors add in series vs parallel?

In parallel, capacitances add directly: C_total = C1 + C2 + C3. In series, reciprocals add: 1/C_total = 1/C1 + 1/C2 + 1/C3. Series connections reduce total capacitance but increase voltage rating.

What is the formula for capacitor discharge time?

Discharge time depends on the RC time constant: τ = R × C. A capacitor discharges to ~37% after 1τ, ~14% after 2τ, ~5% after 3τ, and ~2% after 4τ. Full discharge is typically considered 5τ.

Are these capacitor calculators free to use?

Yes, all our capacitor calculators are completely free with no registration required. Use them as many times as you need for your engineering projects.

Built for Critical Systems

Our engineering team validates every component for mission-critical reliability. Need help selecting the right capacitor?