TipRentBillFree · no sign-up · your data never leaves your browserFree · no sign-up · nothing ever leaves your browser
One gas bill, and nothing else. The whole household account lives on the utility cost calculator; this page works out the gas bill only — the difference between two meter readings, the unit the meter reads in, the rate, the fixed service charge and any tax. Enter the two readings from your own bill and this gas bill calculator prints the usage charge, the fixed charge, the tax, the total, the cost a day and the all-in cost per therm — no sign-up, nothing to install.
Your gas bill for 40 therms
$1.20 per therm × 40 therms + $9.00 fixed charge
The two readings are subtracted and nothing else on the page sets the usage: 120 minus 80 is 40 therms. The order matters — if the reading now is the lower of the two, the page says so rather than printing a negative bill.
RateMultiplies the usage. It is quoted in the unit the meter reads in — per therm, or per CCF if that is what your tariff uses — so switch the unit above before typing it.
The fixed charge is the customer or service charge that arrives whatever the meter says, and it is added to the usage charge. The days are used in one row only: they divide the bill into the cost a day.
Tax and feesA percentage of the usage charge plus the fixed charge, added after both — so it never changes the usage line, only the total. Leave it at 0 if your bill prints taxes as a dollar amount and you have added that amount to the fixed charge instead.
Every figure is carried at full precision and rounded once, to the nearest cent. The per-day row is the total divided by the days in the period, and the all-in cost per therm is the total divided by the usage converted to therms.
The same $9.00 fixed charge under two usages — 40 therms and 90 therms at $1.20 a therm.
The figure above shows one case; this table runs the same formula on five, with the rate held at $1.20 and the fixed charge at $9.00 except where the case says otherwise. Every row can be re-checked against the calculator on this page by typing its inputs in.
| Case | Usage charge | Bill | Per day | All-in per therm |
|---|---|---|---|---|
| 120 - 80 therms, $1.20 a therm, $9.00 fixed, 30 days, no tax | $48.0040 × 1.20 | $57.0048.00 + 9.00 | $1.9057.00 ÷ 30 | $1.425057.00 ÷ 40 |
| 1,340 - 1,250 therms, $1.20 a therm, $9.00 fixed, 30 days, no tax | $108.0090 × 1.20 | $117.00108.00 + 9.00 | $3.90117.00 ÷ 30 | $1.3000117.00 ÷ 90 |
| 96 - 72 therms, $1.20 a therm, $9.00 fixed, 30 days, no tax | $28.8024 × 1.20 | $37.8028.80 + 9.00 | $1.2637.80 ÷ 30 | $1.575037.80 ÷ 24 |
| 120 - 80 therms, $1.20 a therm, $12.00 fixed, 30 days, 5% tax | $48.0040 × 1.20 | $63.0048.00 + 12.00 = 60.00, + 5% = 3.00 | $2.1063.00 ÷ 30 | $1.575063.00 ÷ 40 |
| 135 - 85 CCF, $1.20 a CCF, $9.00 fixed, 30 days, no tax | $60.0050 × 1.20 | $69.0060.00 + 9.00 | $2.3069.00 ÷ 30 | $1.330869.00 ÷ 51.85 therms |
A gas bill is a subtraction before it is a multiplication. The meter block on the bill prints a present reading and a previous reading, and the difference between them is the usage for the period — 120 minus 80 is 40 therms on the default case. Some meters also carry a multiplier printed beside the readings; if yours does, multiply the difference by it before typing it in, because this page takes the usage as already multiplied.
The subtraction is the only place the usage comes from, which is why there is no separate "therms used" box. It also means a reading typed in the wrong order is visible: the page refuses to print a negative bill and says which of the two readings is the lower one.
A therm is 100,000 Btu. The U.S. Energy Information Administration's glossary defines it that way, and its FAQ on converting natural gas prices adds the figure this page uses: "In 2025, the U.S. annual average heat content of natural gas delivered to end-use sectors averaged about 1,037 Btu/cfu. Therefore: 100 cubic feet (1 Ccf) of natural gas equals 103,700 Btu, or 1.037 therms."
Source: U.S. Energy Information Administration — Glossary entry "Therm" ("One hundred thousand (100,000) Btu.") and FAQ "How do I convert natural gas prices in dollars per cubic feet to dollars per British thermal unit or therm?", which quotes the heat content for 2025. Both read at eia.gov on 2026-10-23. The same FAQ states that "the heat content of natural gas may vary by location and by type of natural gas consumer" and tells consumers to ask their own supplier, so 1.037 is a national annual average and not a constant for any one meter.
That one coefficient does two things on this page. It moves a reading between the two units, so the same gas reads 40 therms or 38.57 CCF and 90 therms or 86.79 CCF. And it puts the all-in cost per therm on one scale whatever the meter counts: 50 CCF at $1.20 a CCF is $69.00 for 51.85 therms, which is $1.3308 a therm. The rate field always follows the unit you have selected, so a per-CCF rate is never divided by a per-therm figure.
The utility cost calculator already carries this pair: gas at 40 therms is a mild month, and the same flat at 90 therms pays $108.00 for gas instead of $48.00. This page lands on the same two figures because it is the same arithmetic — 40 × $1.20 = $48.00 and 90 × $1.20 = $108.00. The difference is $60.00, and every cent of it is usage: 50 therms × $1.20. Add the same $9.00 fixed charge to both and the bills are $57.00 and $117.00, still $60.00 apart.
Per day over a thirty-day period that is $1.90 against $3.90. All-in per therm it runs the other way: $1.4250 in the mild month and $1.3000 in the cold one, because the same $9.00 is spread over more therms when the meter has moved further. A budget built on the mild-month total will be short in the cold months, and a comparison built on the all-in rate alone will say the wrong thing about which month was better value.
All-in per therm is the total divided by the therms, so it moves whenever the usage moves even though the tariff has not. At 40 therms the $9.00 fixed charge adds $0.2250 to every therm and the all-in figure is $1.4250. At 90 therms the same $9.00 adds $0.1000 and the figure is $1.3000. At 24 therms it adds $0.3750 and the figure is $1.5750. Three different all-in rates on one unchanged $1.20 rate, which is why two bills are compared by the rate on the bill when the question is the tariff, and by the all-in figure when the question is what the gas actually cost.
A gas bill is not one number for twelve months. In most homes the furnace or boiler is the largest single user, so winter bills dwarf summer ones. The table below works one illustrative year: the heating share is an example figure set by this page, not a state or climate average.
| Use | Therms per year | Rate ($/therm) | Charge |
|---|---|---|---|
| Heating | 600 | $1.10 | $660.00 |
| Non-heating (cooking, water, dryer) | 250 | $1.10 | $275.00 |
| Total | 850 | — | $935.00 |
With the numbers above, heating is 600 of 850 therms, or about 71% of the gas a home uses in a year, yet it lands in only the cold months, so a January bill can be several times a July bill. The columns trace to sources as follows:
The heating therms are not spread evenly — they arrive in perhaps four months. If 600 heating therms hit in 120 days that is 5 therms a day; the other 250 therms over the remaining 245 days is about 1 therm a day. At $1.10, the cold-season daily gas cost is roughly $5.50 versus $1.10 the rest of the year — a five-to-one swing the annual average hides. Budget the winter month against the peak daily rate, not the yearly mean: peak daily cost × 30 is a safer line than annual total ÷ 12. No other page on this site makes that peak-versus-mean comparison for gas, which is why it lives here.
A gas bill is not one number for twelve months. In most homes the furnace or boiler is the largest single user, so winter bills dwarf summer ones. The table below works one illustrative year: the heating share is an example figure set by this page, not a state or climate average.
| Use | Therms per year | Rate ($/therm) | Charge |
|---|---|---|---|
| Heating | 600 | $1.10 | $660.00 |
| Non-heating (cooking, water, dryer) | 250 | $1.10 | $275.00 |
| Total | 850 | — | $935.00 |
With the numbers above, heating is 600 of 850 therms, or about 71% of the gas a home uses in a year, yet it lands in only the cold months, so a January bill can be several times a July bill. The columns trace to sources as follows:
The heating therms are not spread evenly — they arrive in perhaps four months. If 600 heating therms hit in 120 days that is 5 therms a day; the other 250 therms over the remaining 245 days is about 1 therm a day. At $1.10, the cold-season daily gas cost is roughly $5.50 versus $1.10 the rest of the year — a five-to-one swing the annual average hides. Budget the winter month against the peak daily rate, not the yearly mean: peak daily cost × 30 is a safer line than annual total ÷ 12. No other page on this site makes that peak-versus-mean comparison for gas, which is why it lives here.
A gas bill is priced per therm and an electricity bill per kilowatthour, so the two cannot be compared as printed. Convert both to dollars per million Btu and the comparison is one division each. The U.S. Energy Information Administration's units table gives 1 therm = 100,000 Btu and 1 kilowatthour = 3,412 Btu, so a therm is 0.1 million Btu and a kilowatthour is 0.003412 million Btu.
| Fuel | Price per unit | Btu per unit | Cost per million Btu |
|---|---|---|---|
| Natural gas | $1.20 per therm | 100,000 | $12.00 |
| Electricity | $0.16 per kWh | 3,412 | $46.89 |
On those two prices electricity costs 3.91 times as much per million Btu as gas. The break-even runs the other way: gas at $1.20 a therm is the same money per million Btu as electricity at $0.0409 a kWh. Both figures come from the two example prices in the table above, which are values set by this page — not a state average, not a national average, not a supplier's tariff.
The ruler prices the energy sitting in the fuel, not the heat that reaches the room. A furnace, a boiler and a heat pump each turn that energy into delivered heat differently, and that difference is equipment data rather than anything a bill shows. So this page stops at cost per million Btu and does not claim that one fuel heats a home more cheaply. The electricity side, from the meter to the three lines on the bill, is the electricity bill calculator.
It does not report an average gas bill by state, by city, by household size or by square footage. It does not forecast a year from one month, because a heating month and a mild month are not the same usage. It does not quote a state gas price or a state's gas rules. It does not normalise for weather, so a cold month is not adjusted down to an average one. It does not judge whether the bill you are holding is correct, and it does not look for a cheaper supplier or tariff. Each of those needs data this page does not have, so none of them is printed: enter the figures from your own bill and the answer is exact to the cent for that bill.
Splitting the bill is a different question with different arithmetic, and that is the utility bill split calculator — it takes each utility on the basis that fits it, by usage or by headcount, rather than dividing every line the same way.
Subtract last period's meter reading from this one, multiply the difference by the rate, add the fixed service charge, then add tax if your bill charges it. On the default figures: 120 - 80 = 40 therms, 40 × $1.20 = $48.00, plus $9.00 fixed, is $57.00 for the month — $1.90 a day over 30 days. Type your own two readings and the page runs the same four steps.
It works out what the gas you used costs, from the numbers already on the bill: two meter readings, a rate, a fixed charge and a tax rate. Nothing in the arithmetic is specific to a supplier, and the word natural changes nothing — the meter counts therms or hundreds of cubic feet, the tariff prices them, and the bill is the two multiplied plus the fixed charge. A tool that divides a bill you already have between people is doing something else.
The readings are the usage: present minus previous, times any meter multiplier printed beside them. 120 - 80 is 40 therms here, and 40 × $1.20 is the $48.00 usage charge. The fixed service charge and the tax are the rest of the bill, and the meter sees neither of them. If your meter reads in hundreds of cubic feet rather than therms, switch the unit at the top of the form and enter the rate per CCF — the page still quotes the all-in cost per therm.
Because the fixed service charge and the tax are not in the rate. On the default case the usage is $48.00 and the bill is $57.00, so $9.00 — 15.79% of the bill — is there at zero usage. Tax is then charged on the usage plus the fixed charge, not on the usage alone. If the gap is larger than those two lines explain, the rate on the bill is probably an average of tiered blocks.
On these rates, going from 40 therms to 90 therms adds $60.00 — 50 therms × $1.20 — and the bill goes from $57.00 to $117.00. The fixed charge is identical in both months, which is why the whole difference is usage. Per day over thirty days that is $1.90 against $3.90.
A therm is a measure of heat — 100,000 Btu, per the U.S. Energy Information Administration's glossary. A CCF is a measure of volume — one hundred cubic feet. EIA's FAQ on converting natural gas prices states that the 2025 U.S. annual average heat content was about 1,037 Btu per cubic foot, so 1 CCF is 103,700 Btu, or 1.037 therms. That is the coefficient this page uses, and the same FAQ warns the heat content varies by location and consumer, so check your own bill before treating 1.037 as exact for your meter.
Not on this page: it works out one bill and stops there. Dividing it is a separate question with its own arithmetic — by headcount, by usage, or equally — and that is the utility bill split calculator, which takes each utility on the basis that fits it.
No. It does not quote an average by state, by city or by household size, and it does not forecast a year from one month, because a heating month and a mild month are not the same usage. Enter the rate from your own bill and the answer is exact to the cent for that bill; anything wider than that would be a guess dressed as a figure.