Auto Grading for Google Classroom, With Teacher Review
ClassLens automates the first grading pass: rubric scoring, personalized feedback, and class-wide analysis. It does not automate teacher approval or return. You review, edit, or override every draft before students see it.
No login for the sample. 30-day full free trial, no credit card. Free plan after the trial, 100 submissions per month.
Built by a teacher with 22 years of classroom experience. Not a tech company guessing at what teachers need.
You Already Know the Problem
You teach five periods. Each class has 30-plus students. A single written assignment generates 150 submissions. At 10 minutes per paper, that is 25 hours of grading for one assignment.
So you make trade-offs. You assign less writing. You give shorter feedback. You push grading to weekends and late nights. You know you could be a better teacher if you were not drowning in a stack of papers every week.
Grading is one of the largest recurring demands on a teacher's week. Research from SOLVED Consulting found that providing truly personalized feedback on every assignment could push teacher workloads to 43-58 hours per week on grading alone. That is not sustainable. It never was.
ClassLens exists because the teacher who built it spent 22 years making those same trade-offs and finally had the tools to fix it.
How Auto Grading in Google Classroom Works
Google Classroom already auto-scores Forms quizzes with an answer key; essays, short answers, and rubric-graded work are what it leaves manual, and that is the first pass ClassLens automates.
ClassLens is not a generic AI tool that happens to support Google Classroom. It was built from the ground up for teachers who live in Google Classroom every day. The entire workflow stays inside the ecosystem you already use.
Step 1: Connect Your Google Classroom
Sign in with your Google account. ClassLens imports your courses, assignments, and student submissions directly from Google Classroom. No CSV uploads, no copy-paste, no switching between platforms.
Step 2: Configure Your Grading Preferences
This is where ClassLens differs from most AI grading tools. You control the grading, not the AI.
Set your preferences before each grading job:
- Strictness level: Standard, Lenient, Understanding, or Effort-Based. You decide the bar.
- Feedback style: Professional, Slightly Informal, or Informal.
- Feedback length: Brief comments or detailed paragraph-level analysis.
- Late work policy: Define how late submissions are handled: full credit, percentage deductions, or zero credit. The AI applies your policy automatically.
- Rubric criteria: Upload your rubric and the AI evaluates each submission point by point against your standards. Not arbitrary ones.
Your preferences are saved and applied to future assignments. Set it once, adjust when you need to.
Step 3: Review and Return
ClassLens grades every submission and saves the results as drafts in Google Classroom. Nothing reaches your students until you approve it.
Review the AI-generated grades at your own pace. Make adjustments where you see fit. Then return grades to students with a single click, or export everything to Google Sheets for your records.
The AI is the assistant. You are the authority.
Teacher Review Is Required
In our May 2026 study of the Gemini 2.5 Flash-Lite Standard configuration on expert-scored ELLIPSE essays, ClassLens scored a quadratic-weighted kappa of 0.623. For reference, two trained human raters scoring the same essays agreed at 0.612, though that is a rater-to-rater comparison, so read it as context rather than a like-for-like baseline. These are historical findings, not Gemini 3.8 accuracy or fairness results. Every ClassLens result is still a draft. You review, edit, or override it before anything reaches a student.
What Makes ClassLens Different from Other AI Grading Tools
Most AI grading tools treat Google Classroom as one integration among many. ClassLens treats it as the foundation.
Read more about how ClassLens surfaces class-wide knowledge gaps, or explore a live sample Knowledge Gap Report with no login.
After a grading job, ClassLens aggregates the results across your entire class and generates a Knowledge Gap Report. It is skipped when you have turned the report off, when too few submissions came back with scored criteria to meet your minimum, and when a job ends needing you to reconnect Google. This tells you what your students understood, where the common misunderstandings are, and which concepts need re-teaching.
A veteran AP History teacher grading DBQs needs a different standard than a first-year teacher grading reading responses. ClassLens adapts to the teacher, not the other way around. Strictness, feedback tone, feedback length, late work handling are all configurable.
Essays, short answers, lab reports, handwritten work (photographed or scanned), CAD drawings, student-drawn graphs, PDFs, slides, uploaded audio and video submissions, and multi-file submissions. If a student can submit it to Google Classroom as a document, image, PDF, or uploaded audio or video file, ClassLens can grade it.
Assignments import directly with no manual setup. Grades write back as drafts in Google Classroom. Student submissions are downloaded for grading and discarded afterwards. The workflow matches what you already do.
ClassLens vs. Google's Native AI Feedback in Classroom
Google rolled out AI-suggested feedback inside Google Classroom in early 2026. It's a useful feature for the teachers who have access to it. Here's how it compares.
Comparison table
Comparison re-checked against Google's own documentation on September 5, 2026. Google's native feature is evolving, so verify anything decision-critical against their current docs.
| Feature | Google native AI feedback (Gemini in Classroom) | ClassLens |
|---|---|---|
| Available to | Education Plus or Teaching & Learning add-on subscribers | Any Google Classroom teacher (free tier with 100 submissions/month) |
| Grades against your rubric | No (drafts feedback only) | Yes (scores criterion by criterion) |
| Class-wide knowledge gap synthesis | No | Yes (per-assignment, per-criterion, per-period) |
| Batch grading | One submission at a time | 30+ submissions in a single 2-5 minute batch |
| Teacher review before student sees grade | Yes (drafts) | Yes (Classroom drafts or Batch Review Dashboard) |
| Auto-grade and release without review | No | No (auto-return permanently eliminated 2026-04-12) |
| Knowledge Gap Reports | No | Yes |
Why use ClassLens if you have Google native feedback
Two reasons.
One: Google's feature drafts feedback. It does not grade. A teacher still has to determine the score, weigh it against the rubric, and enter it. ClassLens does the scoring against your rubric in addition to writing feedback; that's the part that takes the hours.
Two: Google's feature is per-student. It writes a comment for one essay at a time. It does not aggregate. After 30 students, you still don't know what your class as a whole missed. The Knowledge Gap Report is the answer to that question.
Many teachers use both. Google's drafted feedback is fine for quick formative checks. ClassLens is for the assignments where you actually need scores and class-level diagnostics, the ones that take your evenings now.
We respect the work the Google Classroom team is doing. They built a useful feature. We built a different one, for a different part of the grading workload. To read more about how AI grading should be used responsibly in the classroom, see the ethics of AI grading.
Student Privacy Is Not an Afterthought
If you are a teacher, you know that using a new tool means asking about student data. ClassLens was designed from the start with FERPA compliance built into the architecture.
- Transient processing: Student submissions are downloaded, graded, written back to Google Classroom, and discarded. No persistent student PII is stored on ClassLens servers.
- Google Cloud Vertex AI under the Cloud DPA: your data is never used to train Google’s foundation models.
- Encryption: data is encrypted at rest and in transit, and OAuth tokens are encrypted at rest with AES-256-GCM.
- Teacher-initiated only: Nothing happens without your explicit action.
- School/district authorization: teachers represent that their school or district has authorized the use of AI-assisted grading tools before they process student education records through the Service (Terms, Section 4).
- Data privacy agreements: we execute the SDPC National Data Privacy Agreement, or your district’s own data processing agreement.
You should not have to choose between using AI and protecting your students. With ClassLens, you do not have to.
Built by a Teacher, for Teachers
ClassLens was not built in a Silicon Valley office by engineers who have never been inside a classroom. It was built by Steven Swanson, a teacher with 22 years of experience who grades 150-plus papers every week.
The features in ClassLens exist because they solve problems Steven faces in his own classroom. Knowledge Gap Reports exist because he wanted to know what his class was missing. Configurable strictness exists because formative check-ins and summative essays require different standards. Draft mode exists because no responsible teacher wants AI sending grades to students unsupervised.
This is a tool built by someone who uses it. Every design decision reflects real classroom experience, not market research.
More on this in our post on the ethics of AI grading.
The Time You Get Back
Here is the math for a teacher with 150 students.
Manual Grading
25 hours
150 papers at 10 minutes each
With ClassLens
~7 hours
AI grades in minutes, review at 2-3 minutes each
Time Saved
18+ hours
Per assignment cycle
According to a 2025 Gallup survey, teachers who use AI tools weekly save an average of 5.9 hours per week. That is equivalent to getting back 6 full weeks over the course of a school year.
Get Started in Five Minutes
Individual teachers can try ClassLens without a download, a Chrome extension, or a Classroom add-on. Managed Workspace domains may require administrator approval first.
Sign in with Google
Use your Google account (personal or Workspace).
Select an assignment
ClassLens imports your courses and assignments from Google Classroom.
Set your preferences
Choose your strictness, feedback style, and late work policy.
Grade
ClassLens processes your submissions and saves grades as drafts.
Review and return
Check the AI's work, make adjustments, and return to students.
Every new account starts with a full free month of grading at full volume, no credit card. The clock does not start until you grade your first assignment, and after the month you keep a free plan with 100 submissions/month.
For a deeper walkthrough, read our complete guide to automated grading in Google Classroom.
Frequently Asked Questions
Is ClassLens free?
Yes. The free tier includes 100 submissions per month, enough to grade about 3-4 typical class assignments. Paid plans (Pro at $10/month for 1,000 submissions, Max at $20/month for 5,000) are for teachers grading regularly. No credit card required to start.
What counts as one submission?
One student's work on one assignment. If 28 students turn in an essay and you grade the batch, that is 28 submissions. The free plan's 100 submissions per month covers about 3 to 4 typical class sets. Grading with the Advanced model uses 3 credits per submission instead of 1.
Is the free trial the same as the free plan?
They are two things you get in sequence. Every new account starts with a full free month at full volume, and the clock does not start until your first grading run. When the month ends, you keep the permanent free plan of 100 submissions per month. No credit card is required for either.
Does ClassLens require a Google Classroom add-on or Chrome extension?
No. ClassLens is a web app you reach by signing in with Google, so there is no Chrome extension to add and no Classroom add-on to configure. It imports your assignments and saves draft grades for teacher review. Districts that prefer to deploy it centrally can install the ClassLens listing from the Google Workspace Marketplace, but an individual teacher does not need to.
How much does a Google Classroom grading assistant cost?
Every account starts with a 30-day full free trial. After that, the Free plan includes 100 submissions per month. Pro is $10 per month for 1,000 submissions, and Max is $20 per month for 5,000 submissions.
How does ClassLens compare to Google's built-in AI feedback in Classroom?
Google's native AI feedback drafts written comments for one student at a time. ClassLens grades against your rubric, scores submissions, writes feedback, and aggregates results into a class-wide Knowledge Gap Report. Many teachers use both. See the comparison table above for a full side-by-side.
Does ClassLens replace teacher review?
No. Every grade ClassLens produces is a draft you control, in both return modes. Draft Only saves the draft grade in Google Classroom for you to check there. Grade & Review routes the batch through the Batch Review Dashboard, where you review, edit, or override, then click "Return Checked" to release. Auto-release without teacher review was permanently removed from the product on April 12, 2026. There is no setting that bypasses your review.
Are student submissions stored?
Application grading copies are temporary: deleted after use, with at most 48 hours as the outer expiry bound for unfinished jobs. Grades are written back to Google Classroom. Opaque grading and opt-out identifiers can persist. Provider caching, email suppression records and recipient or support mailbox copies have separate retention periods. Privacy Policy Sections 6 and 7 describe those records and deletion limits. Read the retention details.
Which assignment types does ClassLens grade well?
Open-ended rubric-graded work: essays, short-answer responses, paragraph responses, lab reports, reflections, source analyses, written problem solutions, and project write-ups. ClassLens also reads multimodal submissions natively: handwritten work (photographed or scanned), hand-drawn graphs, sketches, and free-body diagrams, CAD drawings, and lab writeups that mix text, tables, and figures. It grades best against a clear rubric; it is less suited to raw source-code files (most are not a supported upload type and come back marked as skipped, so have students submit a screenshot of the code and console output instead), password-protected files, and highly subjective creative work with no defined rubric. Multiple-choice and exact-match questions don't need ClassLens; Google Classroom handles them natively.
Can I customize the rubric?
Yes. Paste your existing rubric, upload it, or build one inside ClassLens. Up to ten criteria, any weighting. ClassLens grades against the rubric you wrote; it does not invent criteria or change them mid-batch.
What AI model does ClassLens use?
Both grading tiers use Gemini 3.8 Flash via Google Cloud Vertex AI in the US multi-region. Standard uses LOW thinking; Advanced uses the provider default, MEDIUM. Both are governed by the Google Cloud Data Processing Addendum. You choose the model per assignment based on stakes and complexity.
How accurate is ClassLens grading?
We publish our accuracy data instead of asking you to take our word for it. Our published May 2026 study of the Gemini 2.5 Flash-Lite Standard configuration measured a quadratic-weighted kappa of 0.623 on expert-scored ELLIPSE essays, against 0.612 for human-to-human agreement on the same essays. Its demographic-bias testing found no significant bias across the groups evaluated. Those historical findings do not establish the accuracy or fairness of Gemini 3.8. ClassLens is built to deliver a teacher-reviewable draft, not a final grade: Draft Only writes the draft grade to Google Classroom for you to check there; Grade & Review routes the batch through the Batch Review Dashboard, where you review, edit, or override before releasing grades and feedback. In both modes, no student sees a grade until you release it. The full study is here: our accuracy and bias results.
What compliance documentation can districts review?
ClassLens is Google OAuth verified (April 2026), SOC 2 Type I attested (Percilchofe CPA LLC, April 2026), CASA Tier 2 reviewed (TAC Security, April 2026), a CISA Secure by Design Pledge signatory (April 2026), and COPPA-aligned. The full district packet (security overview, NDPA exhibits, attestation reports) is available for school districts.
Does ClassLens work outside Google Classroom?
Google Classroom is the primary integration today. Canvas LMS support is planned but not yet built. If your district uses a different LMS, contact us; we want to know which platforms matter most.
What does ClassLens cost for a school district?
District pricing is invoiced annually based on student enrollment, tiered: small districts (under 5,000 students) at $10 per student, medium (5,000-15,000) at $8, large (15,000+) at $6. District admin features and the pricing request form are at for school districts.
Can ClassLens generate Knowledge Gap Reports for any rubric-graded assignment?
Yes. The report is rubric-driven: any assignment graded against a rubric in ClassLens produces a Knowledge Gap Report automatically. No extra setup, no extra cost. The report is part of every batch.
Ready to Grade Smarter?
Stop spending your evenings and weekends buried in papers. ClassLens gives you AI-assistive grading that connects directly to Google Classroom, respects your standards, and gives you back the time grading takes away.
Free month included. No credit card required. Set up in under five minutes.
ClassLens is also available for school districts with volume pricing and admin controls.