To fill out a calibration request form, you need the instrument’s manufacturer, model number, serial number, and any internal asset tag; the service level you want (NIST-traceable or ISO/IEC 17025 accredited); the specific test points and tolerances the lab should measure against; whether the lab should adjust the instrument or only report readings; and the previous calibration certificate number if you have one. Get those fields right and the lab can start work the day your package arrives. Get them wrong and the job sits on hold until you answer questions.
Gather the Equipment Details Before You Open the Form
Pull the technical identifiers for each instrument first. At minimum: manufacturer name, model number, and serial number. If your organization uses internal asset tags or equipment IDs, have those in front of you too. The lab uses this information to look up the manufacturer’s published specifications, choose the right reference standards, and confirm the instrument is within its serviceable range. A transposed serial number or wrong model number is one of the fastest ways to stall a request, because the lab will hold the job until you correct it.
Know the instrument’s current calibration status as well. Locate the previous calibration certificate if one exists. Labs compare new results against prior data to track drift, and many forms ask for the previous certificate number or calibration date. If the instrument has never been calibrated, was recently repaired, or suffered a drop or impact, note that on the form. That history tells the technician whether to expect normal performance or to look harder for internal damage.
Pick the Right Service Level
Most providers offer at least two tiers, and the choice is not cosmetic. Picking the wrong one either wastes money or leaves you with a certificate your quality department will not accept.
NIST-traceable calibration means the lab certifies that the reference standards used connect back to the National Institute of Standards and Technology through an unbroken chain of documented comparisons, tying the measurements to the International System of Units. A NIST-traceable certificate on its own does not verify the competence of lab staff or the rigor of the lab’s internal processes. It speaks only to the traceability of the standards.1Mensor. What is the Difference Between NIST and ISO/IEC 17025 Accredited Calibrations
ISO/IEC 17025 accredited calibration goes further. An accredited lab has been audited by a recognized accreditation body that evaluated its personnel competency, equipment, procedures, and quality management system. The resulting certificate includes measurement uncertainty values and a traceability statement, both required under the standard. For critical applications where liability is in play, such as medical devices, aviation instruments, and nuclear plant sensors, this is typically the level a quality manual will require.2ISO. ISO/IEC 17025:2017 – General Requirements for the Competence of Testing and Calibration Laboratories1Mensor. What is the Difference Between NIST and ISO/IEC 17025 Accredited Calibrations
For general reference instruments in a low-risk setting, like a tire gauge, a shop air compressor dial, or a torque wrench for routine auto work, NIST-traceable is usually enough. If the measurement feeds a product release decision, a safety system, or a billing calculation, choose ISO/IEC 17025 accredited. Your company’s quality manual or a customer contract often dictates the answer. If you are unsure, check with your quality department before submitting the form, not after.
Specify Test Points, Tolerances, and Whether to Adjust
This is the section that separates careful requests from careless ones. A standard calibration checks the instrument across its full range at the manufacturer’s default test points. If your instrument operates in a narrow band, you can request custom calibration points concentrated in the range that matters. A pressure gauge rated 0–500 PSI used only between 80 and 120 PSI should be calibrated with points inside that window, not spread across the full span.3Vaisala. Custom Calibration
List the specific measurement values where you need readings. If your tolerance limits are tighter than the manufacturer’s published specifications, state them explicitly. The lab needs your acceptance criteria, not just the manufacturer’s, to issue a meaningful pass or fail. Leaving the section blank usually defaults the job to the manufacturer’s standard points and tolerances, which may not match your operational needs.
Forms also ask whether you want the instrument adjusted if it falls outside tolerance, or simply reported as-found. “Calibrate and adjust” means the lab will bring the instrument back into spec if possible. “Calibrate only” means a data report showing where the instrument reads, with no corrections. Some quality systems require as-found data before any adjustments, because that data tells you whether measurements taken since the last calibration are still valid. Decide which you need, and mark the form accordingly.
If you want a conformity statement, meaning a clear pass or fail determination against your specified tolerances printed on the returned certificate, say so on the request form. Not all certificates include one by default, and a raw-data certificate can create audit headaches if your quality system requires explicit pass/fail documentation.
Fill Out the Form
Use the form from the lab you are sending the equipment to. Check their website for a downloadable PDF or an online portal. Most accredited labs offer one or both. The lab’s own form has the data fields their intake system actually processes, which a generic template may not. Some original equipment manufacturers also provide forms tailored to their product lines.
A typical form asks for:
- Requester information: your name, company, shipping address, phone, and email.
- Equipment identification: manufacturer, model, serial number, and internal asset tag.
- Service requested: calibration tier, whether to adjust or report only, and any custom test points.
- Tolerance or acceptance criteria: the performance specifications the instrument must meet.
- Calibration due date: when the current calibration expires, if applicable.
- Previous calibration certificate number, which lets the lab link the instrument’s history.
- Known issues or damage: malfunctions, drops, or environmental exposure since the last calibration.
- Authorization and signature from the person approved to authorize the work and the fees.
Check every serial number and model number character by character. A single transposed digit pulls the wrong specification sheet, and you may not see the error until the certificate arrives and your quality team rejects it. If you are submitting multiple instruments on one form, confirm each line matches the physical equipment in the box. Mismatches between form and equipment are one of the most common reasons labs put a job on hold.
Attach the supporting documents the lab might need: the most recent calibration certificate, manufacturer specification sheets, or a short description of a recent malfunction. If the instrument has a history of drifting in a particular direction, mention it. More context lets the technician work more efficiently.
Submit the Form and Ship the Equipment
Labs accept submissions through an online client portal, by email, or on a printed copy packed with the equipment. A portal submission usually generates a Return Material Authorization (RMA) number. Write the RMA clearly on the outside of the shipping container and on a printed copy of the form inside the box. Labs process dozens of incoming packages a day, and an unmarked box without an RMA can sit in receiving before anyone identifies the sender.
Turnaround times vary with service level and lab workload. As a general benchmark, NIST-traceable calibration often runs 5 to 10 business days from the date the lab receives the equipment, and ISO/IEC 17025 accredited calibration typically runs 10 to 15 business days.4National Instruments. Calibration Services Many labs offer expedited service as fast as 3 business days for an added fee. Plan for backup instruments during the service window.
Packing and Shipping
Precision instruments need more than a cardboard box and some packing peanuts. Use the original manufacturer’s packaging if you still have it, or ask the lab for guidance on packing the specific instrument. Fragile or high-value equipment should be double-boxed with foam inserts that prevent movement in transit. Standard carrier liability often falls short for precision instruments, so consider shipping insurance that matches the actual replacement value.
If the instrument contains lithium batteries, which is common in portable meters, data loggers, and handheld analyzers, federal shipping regulations under 49 CFR 173.185 apply. The battery must be prevented from activating during transport, usually by disconnecting it or taping over the power switch. Packages containing lithium-ion batteries packed with equipment ship under UN3481 and may require a lithium battery handling mark on the outer box. Check current marking and documentation requirements with your carrier before you ship.
Tracking the Request
After the lab receives the package, you should get an automated confirmation. Most labs let you track the job through the same portal where you submitted the form, from initial inspection through testing, any adjustment, and return shipment. Use that visibility to coordinate with operations. If the lab finds damage or an issue that needs a repair quote, they will typically contact you before proceeding, which can extend the timeline.
What to Confirm Before the Certificate Comes Back
The certificate is the whole point of the exercise, so make sure the form you submit will produce one you can use. Under ISO/IEC 17025, the certificate must include the laboratory’s name and accreditation details, the instrument’s identification, the date of calibration, the method used, the environmental conditions during testing, the measurement results with units, a statement of measurement uncertainty, and a traceability statement linking the results back to SI units.5National Institute of Standards and Technology. ISO/IEC 17025:2017, Section 7.8 – Reporting of Results
Two data sets deserve attention when the instrument returns. As-found data is the readings the lab took before any adjustments, which tells you how the instrument was actually performing in your facility since its last calibration. If the as-found data falls within your acceptance criteria, every measurement you took with that instrument in the interval is supported. As-left data is the readings after any adjustment or repair, confirming the instrument meets specifications going forward. If no adjustment was needed, as-found data serves as as-left, and only one set of results appears on the certificate.6Mensor. What Does As-Found and As-Left Data Mean in a Calibration
One boundary worth naming: certain instruments carry federal calibration obligations that go beyond anything on the request form. OSHA requires instruments used to monitor atmospheres in permit-required confined spaces to be kept in calibration with a minimum accuracy of ±10 percent, and audiometers used in hearing conservation programs have calibration requirements tied to specific ANSI standards.7UpCodes. Calibration of Test Instruments If your instrument falls under a regulation like this, note the applicable rule on the form so the lab understands the compliance context and does not default to the manufacturer’s standard tolerances when yours are tighter.