Plan and billing

Calculation engine updated to 1.18.3. Saved work is recomputed, and any change is flagged when you open it.

Charts on Logic Power, Trace Width, Junction Temperature and Trace Inductance match the answers beside them.
Units read plainly: Ω/sq, ppm/°C, °C/mV, dB/in, and ratios as 5.3:1.
A Board profile button on every calculator it fills, and a Fab profile button where fab limits apply.
Shorter labels, with the detail behind a ? beside each field.
Parameter sweep: every step is drawn and named as in its table, on linear and log axes.
Worst-case corners: sampled parts stay inside their tolerance.

Calculation engine updated to 1.18.1. Saved work is recomputed, and any change is flagged when you open it.

Three calculators: Transient Thermal Impedance, PDN Target Impedance, and AC Resistance, Skin Effect & Trace Loss.
Every calculator judges its headline answer against a stated limit, or says why no verdict applies.
Saved work that the current engine answers differently is marked Answer changed in Your work, with a link to what changed.
Recent can be cleared, or switched off, in Your work.
The About page counts calculators the same way as the rest of the site.

Plans. The calculators, verdicts and equations stay free for ever, with no account. Pro adds version history, parameter sweeps, worst-case corners, compare, full exports and unlimited signed reports, and every new account gets 14 days of Pro with no card.
Parameter sweep: vary one input over a range and see the answer and verdict at every step, as a table and a curve, with CSV export.
Compare two saved calculations side by side, with every difference marked.
Version history: every edit to a saved calculation is kept.
Pro features show a preview with a small Pro mark, never inside a result. If a plan ends, nothing is deleted or locked.

Save without an account: Ctrl-S keeps the calculation on this device, offline too, with a title, project and notes. Sign in later and it joins your account.
Continue with these values: links under the results carry your numbers into the next calculator.
Board profile: enter copper weight, thickness, dielectric, ambient and junction limit once, in Your work, and every calculator that asks for them fills them in.
Recent, at the top of the calculator list: your last computations, each a link that reproduces it.
Your work shows how much of your plan is used, filters by tag, and offers undo when you delete.

Calculation engine updated to 1.8.1. Saved work is recomputed, and any change is flagged when you open it.

Show working under the answer on the ten most-used calculators: the equation with your numbers in it.
The headline answer stays in view until the result scrolls into view, at every width.
An empty number field shows the shorthand it accepts, such as 4k7, 100n and 3V3.
3V3 reads as 3.3 V, just as 4k7 reads as 4.7 kΩ.
A comma reads as a decimal point: 2,5 is 2.5 and 4,7k is 4.7 kΩ. Grouped thousands still work, as in 1,000.5, and an ambiguous value is flagged rather than guessed.
Areas and volumes print in a clear unit, such as 25500 µm² or 0.5 mm³.
Every calculator marks one headline answer, with the values that drive the next decision beside it.

Calculation engine updated to 1.7.0. Saved work is recomputed, and any change is flagged when you open it.

Wire Gauge & Voltage Drop: the AWG a run needs for its current and drop, or what a chosen gauge does.
Crystal Load Capacitance: the C1 = C2 pair for a crystal’s C_L, and the ppm error of the pair you have.
Via Stub & Back-drill: the stub’s quarter-wave resonance against your data rate, and the longest stub that stays clear of it.
Trace Inductance & di/dt: partial and loop inductance of a trace, and the voltage a current step produces.
Via & Pad Geometry: annular ring after drill registration, aspect ratio and clearance against your fab’s capability, and the smallest pad that passes.
Copy results on every calculator: inputs, answers, verdicts and the link, ready for design notes and reviews.
Saved calculations can be pinned to the top of your work and carry a note.
On a phone the headline answer stays in view while you edit inputs, and a calculator page prints as a clean document.
Numbers in preset chips and option lists read correctly on Arabic pages.

Calculation engine updated to 1.5.0. Saved work is recomputed, and any change is flagged when you open it.

The impedance calculator also solves in reverse: give a target impedance and it finds the trace width, for every line type.
Fabrication tolerances on w, h and ε_r give worst-case minimum and maximum impedance.
The cross-section has its own panel, and delay is behind a toggle.
Chart cursors read plain numbers, such as 0.20 mm, and move in finer steps.

Calculation engine updated to 1.4.0. Saved work is recomputed, and any change is flagged when you open it.

The impedance calculator covers six line types: surface and embedded microstrip, symmetric stripline, edge-coupled differential microstrip and stripline, and grounded coplanar waveguide.
It now uses the Hammerstad-Jensen and Cohn/Wadell models. Saved impedance numbers shift by a few percent, and the page explains the change when you open them.

Calculation engine updated to 1.3.0. Saved work is recomputed, and any change is flagged when you open it.

The Voltage Divider takes its tolerance from the series you pick, for example ±1 % for E96.
Report a problem, in the footer of every page, with no account needed.
The consulting page has a form: pick what you need and describe the work.
A Most popular shelf at the top of the calculator index.
Saved calculations show their inputs, stored answer and verdict in the list.

Charts draw as soon as the page opens.
The MOSFET loss split is a chart, so the three losses compare at a glance.
An account menu in the header: your projects, saved work and sign-out.
Less text on every calculator. The equations stay in view, and the longer discussion is behind More detail.
A What’s new note after each release.

Calculation engine updated to 1.3.0. Saved work is recomputed, and any change is flagged when you open it.

What's new