Approx is a cloud-based quantity takeoff and construction cost estimation software with AutoCAD integration, built for construction companies and technical offices. It combines takeoff, current Turkish public unit prices, cost calculation and reporting in one workflow.

Approx is designed for contractors, construction consultancy firms and independent quantity surveyors who want to standardize technical office, planning, quantity takeoff and cost estimation workflows.

Does Approx work with AutoCAD?

Yes. The official Approx plugin on the Autodesk App Store lets you pick a project and work order inside AutoCAD, take room measurements (area, perimeter, height) from the drawing with the APL command and transfer them directly into Approx takeoff rows. See the AutoCAD docs.

Which public unit prices are included?

The unit price and rate libraries of the Ministry of Environment, Urbanisation and Climate Change (ÇŞİDB), İller Bankası, the General Directorate of Foundations, the General Directorate of Highways, the Ministry of Culture and Tourism, PTT and the Ministry of National Defence, queryable by publication period.

The free plan gives unlimited access to public unit prices and needs no credit card. Workplace features such as takeoff, work orders and report generation are part of the paid plans.

Can we migrate from Excel?

Yes. Approx is designed to bring Excel-scattered processes into a structured workflow. Existing takeoff rows can be imported with an Excel template and the transition is planned around your current methodology.

Can reports be customized?

Yes. Approx produces customizable reports and supporting documents based on the output structure your company needs.

Can Approx adapt to our existing methodology?

Yes. The platform's core strength is letting organizations carry their own methods into a more controlled digital structure.

Terms of Use | Approx

Approx Terms of Use

Effective Date: 01.11.2026
Publisher: Approx.
Contact: info@approx.one

Overview

These Terms of Use ("Terms") govern access to and use of the Approx web platform, the Approx AutoCAD extension, the Metraj Defteri mobile app, the Approx integrations (including the Approx app for ChatGPT) and related APIs (together, the "Services"), provided by Approx ("Approx", "we", "our", "us").

By creating an account, accepting an invitation to an organization, signing in to Metraj Defteri or connecting an integration, you agree to these Terms. If you use the Services on behalf of an organization, you agree to them on that organization's behalf.

Our Privacy Policy explains how we handle personal data and forms part of these Terms.

1. Provider and Eligibility

1.1. The Services are provided by Approx.

1.2. You can reach us at info@approx.one. Formal notices are also sent to this address.

1.3. The Services are designed for construction companies, consultancy firms, technical offices and independent quantity surveyors, and individuals may also use them. You must have the legal capacity to enter into a contract to use the Services. If you use the Services as a consumer, your rights under Sections 13.4 and 14 are reserved.

1.4. Accounts on the Approx platform belong to an organization. An organization's administrators invite and manage its users, and the data its users create is stored in that organization's workspace.

1.5. If you create an organization or accept these Terms on behalf of one, you confirm that you are authorized to bind that organization. The organization is responsible for the actions of the users it admits.

2. The Services

2.1. Approx provides software tools for:

quantity takeoff (metraj), including formula-based takeoff templates and AutoCAD measurement transfer;
project, property (mahal) and work order management;
unit-price lookup from official and custom pricing libraries;
cost estimation; and
report generation and export.

2.2. Approx's role. We provide and operate the software, host your organization's data, and make the features in your plan available as described in these Terms and in our product documentation.

2.3. Official unit price data. Official unit prices are compiled from information published by the relevant public authorities. The official publication is the authoritative source. Verify prices against it before relying on them.

2.4. Third-party services. Authentication (Auth0), hosting (Microsoft Azure), AutoCAD (Autodesk), ChatGPT (OpenAI) and other third-party products are provided by their own operators, not by Approx. See Section 8.

2.5. We may improve, change or remove features over time. We will give notice, as described in Section 15, of any change that materially reduces the core functionality of a paid plan during its current term.

2.6. Metraj Defteri. Metraj Defteri is a free mobile app for recording takeoff notes on site, and it works separately from the Approx platform:

You sign in with a Google account. A Metraj Defteri account is not linked to an Approx organization, so Sections 1.4, 3, 4 and 11 do not apply to Metraj Defteri.
The field-note text you type or dictate is sent to Microsoft Azure OpenAI Service to convert it into measurements. Photos never leave your device.
Daily and monthly usage limits apply.
Exporting to Excel requires you to complete a contact form and verify a corporate email address. Personal email addresses (e.g., Gmail, Hotmail, Outlook, Yahoo, iCloud, Yandex, Proton) are not accepted.
AI-generated measurements are subject to Sections 6 and 7; verify them before use.
You can delete your account from the Profile screen in the app.

3. The Approx App for ChatGPT

3.1. The Approx app in ChatGPT lets you connect your Approx account to ChatGPT, a service operated by OpenAI. OpenAI decides which ChatGPT plans and regions can use the app.

3.2. How you connect. You add the app directly from ChatGPT. The connection uses OAuth: ChatGPT redirects you to the Approx sign-in page, where you approve the connection by signing in with your Approx account. Approx does not receive your ChatGPT password, and ChatGPT does not receive your Approx password. ChatGPT receives an access token limited to the permissions Approx defines for this integration.

3.3. What the integration can do. Within your organization, the integration supports:

reading: projects, properties, pricing libraries and pricing items, takeoff and report templates, authorities (kurumlar), uploaded files and reports;
creating: projects, properties (individually or in bulk), authorities and reports, and uploading files;
changing and deleting: updating or deleting projects, properties, authorities and uploaded files; and
downloading: generated reports and uploaded files, through time-limited download links.

The integration does not make purchases, payments or subscription changes. The supported actions may change over time.

3.4. Organization scope. Every request made through the integration is limited to the organization your Approx account signed in with. The integration cannot reach another organization's data.

4. Actions and Your Responsibility

4.1. Any member of an organization's workspace can connect the integration. The integration acts on behalf of the user who connected it, within that user's organization.

4.2. ChatGPT decides which Approx actions to call based on your conversation. You are responsible for actions taken through your connection, including actions ChatGPT takes on your instructions.

4.3. Review consequential actions before you confirm them, especially deleting projects, properties, authorities or files, bulk-creating properties and generating reports. Deletions made through the integration are permanent and cannot be undone.

4.4. Disconnecting. You can disconnect Approx at any time in ChatGPT's settings.

5. Data Exchanged Through the Integration

5.1. When you use the integration, Approx sends ChatGPT the results of the actions it calls. These can include project and property information, pricing items and unit prices, template and authority information, report status, file names and time-limited download links. ChatGPT sends Approx the parameters of each action, such as search filters or the details of a project being created.

5.2. This data is sent only when you have connected the integration and ChatGPT calls an action on your behalf. We use the data we receive to perform the requested action.

5.3. Once data reaches ChatGPT, OpenAI's handling of it is governed by OpenAI's own terms and privacy policy, not by these Terms or our Privacy Policy. Approx does not control how OpenAI stores or uses conversation content. Check OpenAI's current terms and your ChatGPT data settings before sharing confidential project information.

5.4. Approx keeps technical logs of integration requests for security and troubleshooting, and keeps them only as long as needed for those purposes.

5.5. Our Privacy Policy explains how we handle personal data, including data processed through the integration.

6. AI Output Limitations

6.1. Answers, summaries, calculations and actions produced through ChatGPT or any other AI tool are generated automatically and may be inaccurate, incomplete or out of date, even when they are based on correct data in Approx. An AI tool may also misread an instruction and call the wrong action or use the wrong values.

6.2. Before you rely on any AI-assisted output for a tender, budget, progress payment (hakediş), contract or construction decision, verify the quantities, unit prices, calculations, report contents and underlying assumptions against the source data in Approx and the official publications.

6.3. Approx is not responsible for the content of answers generated by third-party AI services.

7. Professional Responsibility

7.1. Approx supports professional work and does not replace professional judgment. The Services do not provide engineering, quantity surveying, legal, tax or financial advice.

7.2. You are responsible for the accuracy of the inputs, templates, formulas and drawings you use, and for the takeoffs, estimates and reports you prepare and submit. Where a project requires review or sign-off by a qualified engineer, quantity surveyor, lawyer or other professional, you are responsible for obtaining it.

8. Third-Party Services

8.1. ChatGPT/OpenAI, Autodesk AutoCAD, Auth0, Microsoft Azure and any other third-party services you use with Approx are subject to their own terms, privacy policies, availability and account requirements. You must hold any accounts or licenses they require.

8.2. Approx has no partnership with, and is not endorsed by, OpenAI, Autodesk or other third-party providers. Approx does not guarantee the availability, behavior or output of third-party services, and changes they make may interrupt or alter an integration.

9. Customer Content and Intellectual Property

9.1. Your content. All rights to the projects, takeoffs, drawings, files, custom pricing, templates, reports and other content you upload to or create in Approx ("Customer Content") belong to you or your organization.

9.2. Your authorization. You confirm that you have the rights and permissions needed to upload, access and process your Customer Content through the Services, including content belonging to your clients or project owners and data reached through an integration.

9.3. Our limited rights. You grant Approx a limited, non-exclusive right to host, store, copy, process, transmit and display Customer Content only as needed to provide, secure, support and maintain the Services, including sending it to an integration you have connected. We do not sell Customer Content.

9.4. Our intellectual property. Approx owns the Services, the software, the standard templates we provide and the Approx brand. We grant you or your organization a limited, non-transferable right to use the Services in accordance with these Terms. Official unit price data remains subject to the terms set by its original publisher.

9.5. Feedback. We may use any suggestions you send about the Services without any obligation to you.

10. Acceptable Use and Security

10.1. You must not:

access, or try to access, data, accounts or organizations you are not authorized to use;
share login credentials or access tokens, or let anyone outside your organization use your account;
probe, scan or test the Services' security without our written permission, or interfere with their operation;
use automated tools to extract data at volumes beyond normal use, or resell or redistribute the Services or their data except as your plan permits;
reverse engineer the Services except where the law expressly allows it;
upload malware, unlawful content or content you have no right to use; or
use the Services in breach of applicable law or third-party rights.

10.2. Keep your credentials and devices secure, and protect the confidentiality of your project information, including information you choose to share with AI tools. Tell us promptly at info@approx.one if you suspect unauthorized access to your account.

10.3. Organization administrators are responsible for managing their users' access and removing users who should no longer have it.

11. Subscriptions and Payments

11.1. Paid use of the Services is provided under a written agreement or order form between Approx and your organization (the "Contract"). The Contract sets the plan, fees, term, number of users, invoicing schedule, payment terms and renewal and cancellation terms. If the Contract and these Terms conflict on these matters, the Contract prevails.

11.2. Fees are invoiced as set out in the Contract. Applicable taxes, including KDV (VAT), are shown on the invoice.

11.3. For invoices that remain unpaid after their due date and a written reminder, we may restrict access under Section 12.2 until payment is made.

11.4. Refunds are given as provided in the Contract or as required by law.

11.5. The ChatGPT integration is available on all plans at no extra charge. No purchases or payments are made through the integration.

12. Availability, Suspension and Termination

12.1. We work to keep the Services available, but we do not guarantee uninterrupted service. Maintenance, updates, outages at our providers and third-party changes can interrupt the Services or an integration. If the Contract specifies a service level agreement (SLA), that commitment applies.

12.2. We may suspend or restrict an account, a user or an integration's access where needed to prevent a security risk, harm to the Services or other customers, a breach of these Terms, or non-payment under Section 11.3. Where practical, we will notify you first and restore access once the issue is resolved.

12.3. Your organization may stop using the Services at any time. Termination of a paid plan and its effect on fees are governed by the Contract. Either party may terminate these Terms for a material breach that is not remedied within 30 days of written notice, or immediately where the law allows.

12.4. After termination, access to the Services and all connected integrations ends. Customer Content is kept until the organization asks for it to be deleted, and you may request an export in the meantime. Unless the law requires us to keep it, we delete it within a reasonable period after a deletion request. Backups are deleted within up to 90 days, as described in our Privacy Policy.

13. Warranties and Liability

13.1. We provide the Services with reasonable skill and care. Beyond that, and to the extent the law allows, the Services are provided "as is". We do not warrant that the Services will be error-free or uninterrupted or will meet every specific requirement, or that AI output or third-party data will be accurate.

13.2. To the extent the law allows, neither party is liable for indirect losses such as lost profits, lost tenders or loss of business. Approx's total liability for claims arising from the Services is limited to the total fees your organization paid under the Contract to which the claim relates.

13.3. Nothing in these Terms limits liability for intent or gross negligence, for death or personal injury, or any other liability that cannot be limited or excluded under applicable law.

13.4. Nothing in these Terms removes or limits your rights as a consumer under mandatory law.

14. Governing Law and Disputes

14.1. These Terms are governed by the laws of the Republic of Türkiye.

14.2. Subject to Section 14.3, the Ankara Courts and Enforcement Offices have jurisdiction over disputes arising from these Terms.

14.3. If you use the Services as a consumer, you may apply to the competent Consumer Arbitration Committee or Consumer Court under Law No. 6502 on Consumer Protection, including those where you live, within the monetary limits announced each year. Section 14.2 does not restrict these rights.

14.4. Before starting formal proceedings, contact us at info@approx.one so we can try to resolve the issue together.

15. Changes and Contact

15.1. We may update these Terms to reflect changes in the Services, the law or our business. The updated version will be posted on this page with a new Effective Date. We will email organization administrators about material changes at least 30 days before they take effect. If you continue to use the Services after that date, you accept the updated Terms.

15.2. These Terms are published in Turkish and English. If the two versions conflict, the Turkish version prevails.

15.3. For questions about these Terms:
📧 info@approx.one
🌐 https://approx.one/en/support