Yes — Digital Red Pen reads handwritten calculus work and awards step-level partial credit for setup, rule application, and execution. A correct derivative or integral setup earns credit even when arithmetic slips at the end. Calculus is in scope; Algebra 2 is the validated core.
Keyless Grading for Math
Grade handwritten calculus — the setup and the steps, not just the value
In calculus the method is most of the grade. Digital Red Pen reads the chain — setup, rule, execution — and credits each part.
Get started →Why step-level grading matters for calculus
A derivative or integral problem is graded on setup and method as much as the final value: choosing the right rule, applying it correctly, carrying it through. A student who sets the integral up correctly and slips in arithmetic has shown most of the understanding.
Digital Red Pen reads the handwritten steps and awards partial credit from the method under your Desk rules — the same standard on every paper in the stack.
Calculus is in scope, including AP-style free-response step grading; Algebra 2 is the validated core, and you review every grade in The Desk before it's final.
How it works
Scan your stack
Place your student exams with a clean copy of the test at the front. Scan to one PDF — no sorting, no cover sheets, no answer key required.
Upload — it grades in parallel
The system spawns an isolated worker for each exam and grades every paper in parallel — each read independently, at the same time. A full class set finishes in roughly the time a single exam takes, not one-after-another. One bad scan fails alone — it never holds up the rest of the batch.
Review, approve, done
The Desk — the built-in review layer — presents every grade for your sign-off. Override anything. Issue the report. Nothing reaches students until you approve.
What you get back
Partial credit from the steps
The system reads each student's handwritten work — setup, process, intermediate steps — and awards credit for what was correct, not only the final answer.
Per-student reports
Each student's exam comes back with a graded breakdown. Walk into class the next morning knowing exactly who needs what.
Class analytics
Grade distribution, score trends, and problem-level breakdowns — the diagnostic picture for the whole class, without a spreadsheet.
Deadline-safe by design
The isolation architecture means a malformed scan fails alone. Graceful partial results: if a few exams need your eyes, the rest of the batch comes back complete.
"I checked it against my own Algebra 2 grading. It agreed with me about as well as two good teachers agree with each other. Honestly, on the Sunday nights I graded after 9 pm, it was more consistent than I was — I was handing different scores to kids for the same work depending on how tired I felt. The machine doesn't have bad days."— Zack Alexander, co-founder and secondary math teacher
You make the call.
The machine applies the standard. You judge. That is not a disclaimer — it is the design. The Desk is a built-in review layer between grading and the report. Every grade is presented to you before it leaves the system. Override anything; rulings propagate automatically to every matching case in the stack, so one correction covers the whole class.
The system also knows what it is not good at. Handwritten graphs are hard to parse reliably, so graph-heavy problems are flagged and routed to you rather than graded with false confidence. You get the full picture — the grades it is confident in and the ones it is handing back.
Grading
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Start grading tonight →Frequently asked questions
What happens if it gets a grade wrong?
The Desk — the built-in teacher-review layer — surfaces every grade before any report is issued. The system flags low-confidence work (for example, graph-heavy problems where handwritten graphs are hard to parse) and routes those directly to you. You override any grade; the correction propagates to every matching case in the stack. Nothing reaches students until you approve.
How accurate is it?
The grading agreement is described as: it agrees with an experienced teacher about as well as two good teachers agree with each other. The founder checked it against his own Algebra 2 grading. He found it more consistent than himself on the nights he graded when tired — he was handing back different scores for the same work depending on how he felt. The machine applies one standard to paper 1 and paper 150.
What subjects does it work for?
Math only. Algebra 2 is the validated core; Geometry, Pre-calculus, Calculus, Statistics, and middle-school math are in scope. Science is not in scope.
How long does a full class set take?
Digital Red Pen grades every exam in parallel — each paper read independently, at the same time — so a full class set finishes in roughly the time a single exam takes, not one-after-another. We will publish typical timing once we have measured the reworked system.
Does it work for AP Calculus free-response?
It reads multi-step handwritten solutions — derivative and integral setups, rule application, and execution — and awards step-level partial credit under the rules you define. Calculus is in scope; Algebra 2 is the validated core.
Will it credit a correct setup with a wrong final answer?
Yes — that's the core behavior. It reads the steps, so a correct integral or derivative setup earns credit even if the arithmetic slips at the end. You decide the split in The Desk.