Terms of Service

Engine Calculator (the "Company") provides free online engine calculators — including compression ratio tools with dynamic CR via slider-crank geometry, engine preset bore/stroke/chamber references, octane guidance, reverse target solvers, and educational guides — on Engine-Calculator.com (the "Website") for engine builders, machinists, cam grinders, tuners, students, and general automotive enthusiasts. By accessing or using the Website in any way — running a calculation, reading a guide, or citing a result — you agree to comply with these Terms of Service. If you object to any term or condition here, or to any guideline posted on the Website, your sole and exclusive remedy is to immediately discontinue use of the Website.

We may revise, modify, or replace these Terms of Service at any time at our sole discretion. Changes take effect immediately upon posting to this page, and the latest version is always linked from the Website footer. Because the Website is free and requires no account, posting is deemed sufficient notice. You should review these Terms periodically — particularly before relying on calculator output for a real piston order or machining spec.

All output from the Website — static compression ratio, dynamic compression ratio, octane recommendations, reverse target-solver results, slider-crank piston positions, and crank-pressure estimates — is provided for informational, planning, and educational purposes only. It is not a piston manufacturer's specification, not a machinist's confirmed milling amount, not a cam grinder's timing recommendation, not a dyno-tested tuning target, and not professional engine-building advice of any kind.

The Website does not replace a certified engine builder, a professional engine machinist, a cam grinder, a professional tuner, or the authority having jurisdiction over emissions compliance. Actual chamber volume measurement (burette cc'ing), gasket compression set verification, piston dome CMM verification, quench gap analysis, valve shrouding, and dyno tuning are specified and applied differently for every engine and in every application, and their application to your specific engine requires evaluation by qualified professionals. Nothing on this Website creates a professional relationship of any kind.

You agree not to post, transmit, or use the Website in any way that:

• Violates any applicable federal, state, provincial, or local law, including emissions regulations and competition rules where the engine will be used
• Attempts to scrape, crawl, mirror, or bulk-download calculator results, engine preset data tables, or guide content
• Reverse-engineers, decompiles, or extracts the calculation engines — compression ratio, slider-crank geometry, octane guidance, and reverse-solver math — for reuse in another product
• Misrepresents calculator output as a professionally machined piston dome height, a cam timing specification, or a dyno-tested tuning recommendation
• Infringes any patent, trademark, trade secret, copyright, or other proprietary right of any party
• Uses forged headers, rotating proxies, or false identifiers to disguise the origin of requests to the Website
• Disrupts, overloads, or interferes with the normal operation of the Website or its infrastructure

Unless you receive explicit written permission from the Company, you may not copy, reproduce, resell, or exploit any part of the Website for commercial purposes. Quoting a short result with attribution and a link in a forum post, lesson, or engine-build sheet is welcomed; systematic republication is not.

The Website's software, calculation engines, original text, page designs, logos, and graphics are owned by the Company and protected by copyright and other intellectual-property laws.

Manufacturer product names, engine presets, piston designs, cam specs, and technical documents referenced on the Website belong to their respective publishers. The Website independently implements publicly documented compression ratio calculation methods (static CR, slider-crank dynamic CR, polytropic crank pressure, and octane-range consensus) and refers to those publications for identification and educational purposes. This Website is not affiliated with, endorsed by, or sponsored by any piston manufacturer, head supplier, cam company, or standards body, and calculator output is not a substitute for the manufacturer's certified product data sheet, the current editions of the referenced standards, or your engine builder's measured geometry. Where precise product data matters, consult the manufacturer's published data and the authority having jurisdiction.

Our Privacy Policy explains how the Company collects, uses, and discloses information, and is incorporated into these Terms by reference. In short: the inputs you enter — bore, stroke, chamber cc, gasket, piston, deck, rod length, IVC angle, altitude, octane — are processed locally in your browser and are not transmitted to or stored on our servers. Use of the Website constitutes acceptance of the Privacy Policy as well as these Terms.

The Website contains references to engine families, bore/stroke/chamber values, piston designs, cam timing, fuel octanes, and third-party resources. These references are provided to help you find authoritative sources and are not intended to imply sponsorship, endorsement, or affiliation, or that any trade name, trademark, or logo may be used by you.

Calculator output may be affected by input accuracy, chamber cc measurement error, piston dome CMM variance, actual vs. advertised cam IVC angle, installed gasket compression set, and real-world factors such as quench area, valve shrouding, and turbulence that the tool does not model. If you believe a formula, engine preset bore/stroke, or guide statement is incorrect, contact us with the page URL, your inputs, and the result you expected — we investigate every report and update content to the extent the authoritative sources allow.

The Website is funded by third-party advertising, including Google AdSense. Ads are clearly distinguished from calculator output and editorial content. We do not control, endorse, or warrant advertised products or services, and any dealings between you and an advertiser are solely between you and that advertiser. Advertising cookies and your opt-out choices are described in the Privacy Policy.

The Company may set limitations on your use of the Website, and may modify, suspend, or discontinue the Website — or any part of it — at any time, with or without notice, at its sole discretion.

THE WEBSITE AND ALL CALCULATORS, ENGINE PRESETS, REFERENCE DATA, AND GUIDES ARE PROVIDED "AS IS" AND "AS AVAILABLE" WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING WARRANTIES OF ACCURACY, MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, OR NON-INFRINGEMENT. YOUR USE IS ENTIRELY AT YOUR OWN RISK.

TO THE MAXIMUM EXTENT PERMITTED BY LAW, IN NO EVENT SHALL THE COMPANY BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, OR CONSEQUENTIAL DAMAGES ARISING FROM YOUR USE OF (OR INABILITY TO USE) THE WEBSITE — INCLUDING DAMAGES FROM INCORRECT COMPRESSION RATIOS, MIS-SPECIFIED PISTON DOMES, WRONG OCTANE GRADES, DETONATION DAMAGE, FAILED PISTONS OR RINGS, BLOWN HEAD GASKETS, DYNO-TUNING ERRORS, EMISSIONS FAILURES, PERSONAL INJURY, LOST PROFITS, OR ERRORS IN SLIDER-CRANK GEOMETRY, CHAMBER CC, OR OCTANE FIGURES. SOME JURISDICTIONS DO NOT ALLOW CERTAIN WARRANTY EXCLUSIONS OR LIABILITY LIMITATIONS, SO SOME OF THE ABOVE MAY NOT APPLY TO YOU.

These Terms of Service shall be governed by the laws of the United States, without regard to conflict-of-laws provisions. You and the Company agree to submit to the personal and exclusive jurisdiction of the courts located within the United States for any dispute arising from these Terms or your use of the Website.

If any provision of these Terms is held invalid or unenforceable by a court of competent jurisdiction, that holding shall not affect the validity or enforceability of the remaining provisions, which continue in full force. The Company's failure to enforce any right or provision shall not constitute a waiver of that right or provision, or of any further rights. These Terms, together with the Privacy Policy and the Disclaimer, constitute the entire agreement between you and the Company regarding the Website and supersede any prior agreements.

If you have questions about these Terms of Service, or need to report a violation of them, reach us via the contact page. We read every message and respond to legitimate inquiries.