Calculators and on-site tools
Gas and heating calculators, built into the job.
Work out the gas rate at the meter, size the pipe, check the ventilation and the heat loss, and walk through a tightness test step by step. They work with no signal, and the figure is one tap from the certificate.
14 days free, no card. Then £19 a month for you and £9 for each person you add.
Gas rate
Time the meter, get the heat input, check it against the data plate.
Most modern plates quote Qn, which is net. CV 39.2 MJ/m³, correction 1.02264, gross to net 1.11.
Net heat input
24.08kW
Gross 26.72 kW · 2.4 m³/h
Against the data plate-2.5%
Within the ±5% you'd expect.
- Combi, flat 2Net 27.09 kW · 2.7 m³/h
This is the real calculator's maths. Change a reading and try it. The full gas rate calculator is free, with a meter timer, one-revolution tests, LPG and imperial meters. Guidance only: follow Gas Safe procedures and the manufacturer's instructions.
01The toolbox
Everything in the box.
Four calculators you can use free on the web, three walk-throughs in the app's Tools, and the sums that happen inside the certificates themselves.
ACompartment
Free on the web
No account, no sign-up. The same calculators that are in the app, on any phone.
- Gas rate calculatorHeat input from meter readings, checked against the data plate. Natural gas or LPG, metric or imperial, timed or one revolution.Open free
- Gas pipe sizing calculatorSize a run section by section against one pressure drop limit, in copper or steel, with the fittings counted.Open free
- Gas ventilation calculatorThe permanent ventilation a domestic gas appliance needs, and how many airbricks that comes to.Open free
- Heat loss calculatorRoom by room across a property, with radiators sized for the flow temperature you're actually fitting.Open free
BCompartment
In the app, under Tools
The four above, with your tests saved on the phone, plus three walk-throughs for the jobs that need a procedure.
- Tightness testIGEM/UP/1B Edition 4, step by step: the installation volume from the meter and pipe runs, the limit for the fuel, and the pipework-only retest.
- UP/1 & UP/1A testingNon-domestic strength test, tightness test and purge: which standard, the test times, the limits and the purge volume, with the working shown.
- Unsafe situationsThe Gas Industry Unsafe Situations Procedure (IGEM/G/11) as two questions and a checklist, with the numbers to ring.
CCompartment
Inside the certificates
Some sums belong on the record itself, so they're worked out there, next to the box they fill.
- Gas rate, on the gas recordsOn the gas safety, inspection and service records and the non-domestic commissioning record. Use this figure puts it in the heat input box and keeps the working with the certificate.
- Work it out, on non-domestic testing and purgingThe UP/1 and UP/1A sums inside the PAD12 record. It proposes the figures, you tick the ones you want, and it fills those boxes.
- Tightness steps, on domestic testing and purgingThe Edition 4 procedure and the allowed drop, beside each tightness test on the PAD11 record.
- CO₂ equivalent, on the F-Gas Equipment RecordThe GWP fills in from the refrigerant and the tonnes CO₂e are worked out from the charge. A leak-check interval that's too long for them is flagged.
02Where the answer goes
Worked out once, and put where it goes.
A calculation is only worth something once it's on the record. In Tools, it's one tap from the certificate. On the gas records, the gas rate is worked out on the record itself.
- Kept while you typeWalk off to check the plate or lock the phone, and the readings are still there when you come back.
- Saved with a nameSave a test as Boiler, airing cupboard and open it again later. Saved tests stay on the phone, as working notes rather than records.
- Copied where it's neededOne tap copies the net kW for the certificate box. Copy test puts the whole recap on the clipboard for a job note.
- No signal neededThe tools work offline, in a plant room or a basement, like the rest of the work on site.
Certificate
Landlord/Homeowner Gas Safety Record
Boiler · Kitchen
Gas rate from the meter
- Dial volume
- 0.05 m³
- Time taken
- 70 s
- Compare against
- Net
25.4kW net2.571 m³/h
Heat input
Nothing is written until you press it.
The gas rate helper on the gas safety record. Press Use this figure to fill the heat input box.
03The small print, up front
Guidance, with the working shown.
The IGEM tables behind the tightness and UP/1 tools are still waiting to be signed off by a Gas Safe registered engineer. Until then the tools offer figures and say where each one came from, and nothing goes on a certificate unless you choose it. The standard is the authority, and whether an installation is acceptable is your call.
Tools appears once Gas Safe is switched on in your business's registrations. Engineers have it by default; for other roles it's the View the engineer calculators switch.
- Tightness testLimits from IGEM/UP/1B Edition 4 as published in Gas Safe Register's ISU 133. The same tables sit behind the PAD11 record, so the tool and the form can't disagree.
- UP/1 & UP/1A testingFigures from public documents that reproduce the standards, each shown with its working and where it came from.
- Gas rateStandard arithmetic, shown step by step on the free calculator's page. The calorific value and factors are there to change.
The rest of the job.
Tools come with every OnPoint plan. See pricing or compare OnPoint with what you use now.
For your trade
- Certificates62 UK certificate types, checked as you fill them in, with the gas rate and IGEM sums built into the gas records.
- AI on sitePhotograph an analyser printout or a data plate and the fields fill in, with anything it isn't sure of flagged.
- The engineer's app, offlineJobs, photos, forms, certificates and clock-ins with no signal. It all goes up when you're back.
- Customers, properties and appliancesEvery appliance at every property, with the certificates and visits that go with it.
Questions people ask.
Anything else? Ring +44 7884 697405 or email us.
What calculators does OnPoint have?
Gas rate, gas pipe sizing, gas ventilation and heat loss calculators, plus step-by-step tools for the IGEM/UP/1B Edition 4 tightness test and IGEM/UP/1 and UP/1A testing, and an unsafe situations guide. The gas records have their own gas rate helper, and the F-Gas Equipment Record works out the CO₂ equivalent.
Are the calculators free?
The gas rate, gas pipe sizing, gas ventilation and heat loss calculators are free on our website with no account. In OnPoint they're under Tools with the tightness test, UP/1 and unsafe situations tools, on every plan.
Do they work without signal?
Yes. The tools in the app work offline, and the tests you save stay on the phone.
Can the result go straight on the certificate?
On the gas safety, inspection and service records, the gas rate helper's Use this figure button fills the heat input box and keeps the working with the certificate. In Tools, one tap copies the figure for the certificate box.
What figures does the gas rate calculator use?
A calorific value of 39.2 MJ/m³, a correction factor of 1.02264 and a gross to net factor of 1.11, and you can change all three. It asks whether the plate quotes net or gross, because comparing a gross rate with a net plate reads about 11% high.
Are the IGEM figures approved by Gas Safe?
Not yet. The tightness and UP/1 tables come from published sources and are waiting to be signed off by a Gas Safe registered engineer, so the tools offer figures and say where they came from. The standard is the authority.
Who can use Tools in the app?
Businesses with Gas Safe switched on in their registrations. Engineers have Tools by default, and for other roles it's the View the engineer calculators switch in Roles & permissions.
Take the toolbox to the next job.
£19 a month for you and £9 for each person you add, with the tools, the certificates and every other feature. Try it free for 14 days, no card. Or pay yearly: £190 a year for you and £90 for each extra person, which is 2 months free.